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BACKGROUND: Immediate initiation of antiretroviral therapy (ART) regardless of CD4 cell count reduces risk for AIDS and non-AIDS-related events in asymptomatic, HIV-positive persons and is the standard of care. However, most HIV-positive persons initiate ART when their CD4 count decreases below 500 × 10 9 cells/L. Consequences of delayed ART on risk for non-AIDS-defining and AIDS-defining cancer, one of the most common reasons for death in HIV, are unclear. OBJECTIVE: To estimate the long-term risk difference for cancer with the immediate ART strategy.DESIGN: Multinational prospective cohort study.SETTING: The D:A:D (Data collection on Adverse events of anti-HIV Drugs) study, which included HIV-positive persons from Europe, Australia, and the United States.PARTICIPANTS: 8318 HIV-positive persons with at least 1 measurement each of CD4 cell count and viral load while ART-naive (study period, 2006 to 2016).MEASUREMENTS: The parametric g-formula was used, with adjustment for baseline and time-dependent confounders (CD4 cell count and viral load), to assess the 10-year risk for non-AIDS-defining and AIDS-defining cancer of immediate versus deferred (at CD4 counts RESULTS: During 64 021 person-years of follow-up, 231 cases of non-AIDS-defining cancer and 272 of AIDS-defining cancer occurred among HIV-positive persons with a median age of 36 years (interquartile range, 29 to 43 years). With immediate ART, the 10-year risk for non-AIDS-defining cancer was 2.97% (95% CI, 2.37% to 3.50%) and that for AIDS-defining cancer was 2.50% (CI, 2.37% to 3.38%). Compared with immediate ART initiation, the 10-year absolute risk differences when deferring ART to CD4 counts less than 500 × 10 9 cells/L and less than 350 × 10 9 cells/L were 0.12 percentage point (CI, -0.01 to 0.26 percentage point) and 0.29 percentage point (CI, -0.03 to 0.73 percentage point), respectively, for non-AIDS-defining cancer and 0.32 percentage point (CI, 0.21 to 0.44 percentage point) and 1.00 percentage point (CI, 0.67 to 1.44 percentage points), respectively, for AIDS-defining cancer. LIMITATION: Potential residual confounding due to observational study design.CONCLUSION: In this young cohort, effects of immediate ART on 10-year risk for cancer were small, and further supportive data are needed for non-AIDS-defining cancer.PRIMARY FUNDING SOURCE: Highly Active Antiretroviral Therapy Oversight Committee.

On the last week of May of 2018, a community-based syndromic surveillance system detected mass abortions and deaths of young livestock in northeastern Kenya. Two weeks later, Rift Valley fever (RVF) was confirmed in humans presenting with febrile illness and hemorrhagic syndrome in the same region. A joint animal and human response team carried out an investigation to characterize the outbreak and identify drivers of disease transmission. Here, we describe the outbreak investigation and findings. A total of 106 human cases were identified in the months of May and June 2018: 92% (98) and 8% (8) of these cases occurring in the northern and western regions of Kenya, respectively. Seventy-six (72%) were probable cases, and 30 (28%) were laboratory confirmed by ELISA and/or PCR. Among the confirmed cases, the median age was 27.5 years (interquartile range = 20), and 60% (18) were males. Overall, the case fatality rate was 7% (n = 8). The majority of the confirmed cases, 19 (63%), reported contact with livestock during slaughter and consumption of meat from sick animals. All confirmed cases had fever, 40% (12) presented with hemorrhagic syndrome, and 23% (7) presented with jaundice. Forty-three livestock herds with at least one suspect and/or confirmed animal case were identified. Death of young animals was reported in 93% (40) and abortions in 84% (36) of livestock herds. The outbreak is indicative of the emergence potential of RVF in traditionally high- and low-risk areas and the risk posed by zoonosis to livestock keepers.

Background We implemented a longitudinal study to determine the incidence of Brucella infection in cattle, camels, sheep and goats that were being raised in a pastoral area in Isiolo County, Kenya. An initial cross-sectional survey was implemented to identify unexposed animals for follow up; that survey used 141 camels, 216 cattle, 208 sheep and 161 goats. Sera from these animals were screened for Brucella spp. using the Rose Bengal Plate test (RBPT), a modified RBPT, and an indirect multispecies Enzyme Linked Immunosorbent Assay (iELISA). Results of RBPT and iELISA were interpreted in parallel to determine seroprevalence. A total of 30 camels, 31 cattle, 22 sheep and 32 goats that were seronegative by all the above tests were recruited in a subsequent longitudinal study for follow up. These animals were followed for 12 months and tested for anti-Brucella antibodies using iELISA. Seroconversion among these animals was defined by a positive iELISA test following a negative iELISA result in the previous sampling period. All seropositive samples were further tested using real-time PCR-based assays to identify Brucella species. These analyses targeted the alkB and BMEI1162 genes for B. abortus, and B. melitensis, respectively. Data from the longitudinal study were analysed using Cox proportional hazards model that accounted for within-herds clustering of Brucella infections. Results The overall incidence rate of Brucella infection was 0.024 (95% confidence interval [CI]: 0.014–0.037) cases per animal-months at risk. Brucella infection incidence in camels, cattle, goats and sheep were 0.053 (0.022–0.104), 0.028 (0.010–0.061), 0.013 (0.003–0.036) and 0.006 (0.0002–0.034) cases per animal-months at risk, respectively. The incidence rate of Brucella infection among females and males were 0.020 (0.009–0.036) and 0.016 (0.004–0.091), respectively. Real-time PCR analyses showed that B. abortus was more prevalent than B. melitensis in the area. Results of multivariable Cox regression analysis identified species (camels and cattle) as an important predictor of Brucella spp. exposure in animals. Conclusions This study estimated an overall brucellosis incidence of 0.024 cases per animal-months at risk with camels and cattle having higher incidence than sheep and goats. These results will inform surveillance studies in the area.

Summary Rift Valley fever (RVF) is a viral hemorrhagic disease first discovered in Kenya in 1930. Numerous animal studies have demonstrated that protective immunity is acquired following RVF virus (RVFV) infection and that this correlates with acquisition of virus-neutralizing antibodies (nAbs) that target the viral envelope glycoproteins. However, naturally acquired immunity to RVF in humans is poorly described. Here, we characterized the immune response to the viral envelope glycoproteins, Gn and Gc, in RVFV-exposed Kenyan adults. Long-lived IgG (dominated by IgG1 subclass) and T cell responses were detected against both Gn and Gc. However, antigen-specific antibody depletion experiments showed that Gn-specific antibodies dominate the RVFV nAb response. IgG avidity against Gn, but not Gc, correlated with nAb titers. These data are consistent with the greater level of immune accessibility of Gn on the viral envelope surface and confirm the importance of Gn as an integral component for RVF vaccine development., Graphical Abstract, Highlights • Long-lasting antibodies, predominantly IgG1, target both RVFV glycoproteins • Gn is the principle target of the long-lived RVFV-neutralizing antibody response • IFNγ production from Gn/Gc-specific T cells is modest, Immunology; Virology

Triple-Negative Breast Cancer (TNBC) is the most aggressive breast cancer subtype, characterized by limited treatment options and higher relapse rates than hormone-receptor-positive breast cancers. Chemotherapy remains the mainstay treatment for TNBC, and platinum salts have been explored as a therapeutic alternative in neo-adjuvant and metastatic settings. However, primary and acquired resistance to chemotherapy in general and platinum-based regimens specifically strongly hampers TNBC management. In this study, we used carboplatin-resistant in vivo patient-derived xenograft and isogenic TNBC cell-line models and detected enhanced Wnt/β-catenin activity correlating with an induced expression of stem cell markers in both resistant models. In accordance, the activation of canonical Wnt signaling in parental TNBC cell lines increases stem cell markers' expression, formation of tumorspheres and promotes carboplatin resistance. Finally, we prove that Wnt signaling inhibition resensitizes resistant models to carboplatin both in vitro and in vivo, suggesting the synergistic use of Wnt inhibitors and carboplatin as a therapeutic option in TNBC. Here we provide evidence for a prominent role of Wnt signaling in mediating resistance to carboplatin, and we establish that combinatorial targeting of Wnt signaling overcomes carboplatin resistance enhancing chemotherapeutic drug efficacy. ispartof: FRONTIERS IN ONCOLOGY vol:11 ispartof: location:Switzerland status: published

A cross-sectional study was conducted to determine the seroprevalence of Brucella spp. and Leptospira spp. and risk factors of exposure in cattle in three zones with varying land use types and wildlife–livestock interactions. Five villages were selected purposively; two in areas with intensive livestock–wildlife interactions (zone 1), another two in areas with moderate livestock–wildlife interactions (zone 2) and one in areas where wildlife–livestock interactions are rarer (zone 3). Sera samples were collected from 1170 cattle belonging to 390 herds in all the zones and tested for antibodies against Brucella abortus and Leptospira interrogans serovar hardjo using ELISA kits. Data on putative risk factors for seropositivity of these pathogens in cattle were collected using a questionnaire. The overall apparent animal-level seroprevalence of brucellosis and leptospirosis was, respectively, 36.9% (95% CI 34.1–39.8) and 23.5% (95% CI 21.1–26.0). Brucella spp. seroprevalence was higher in zone 1 than in zones 2 and 3 (χ2 = 25.1, df = 2, P Leptospira spp. seroprevalence than zone 3 (χ2 = 7.0, df = 2, P = 0.029). Results of multivariable analyses identified animal sex (female) and zones (high interface area) as significant predictors (P Brucella spp. For Leptospira spp., important predictors of animal-level seropositivity were animal sex (female), zones (moderate interface area) and herds utilizing a communal grazing reserve. The seroprevalences of Brucella spp. and Leptospira spp. in cattle were higher in areas with moderate to high wildlife–livestock interactions than those with rare interactions.

Staphylococcus aureus (SA) food poisoning results from consumption of preformed S. aureus enterotoxins in food. The enterotoxins are one of the most important virulence factors of the bacterium. The risk posed by contamination of milk intended for human consumption by pathogenic S. aureus in pastoral areas in Kenya is still generally not well documented yet this information is critical for ensuring safety to consumers who sometimes may take unpasteurized milk. This study, therefore determined the prevalence of S. aureus enterotoxin genes in raw milk from cattle, goats, sheep and camels intended for human consumption in northern Kenya. A total of 603 milk samples from 57 zebu cattle, 346 galla goats, 8 red Maasai and dorper sheep, 4 one-humped camel (Camelus dromedaries) and 188 pooled from all animals were collected from Isiolo and Marsabit counties of Kenya. S. aureus isolates were cultured from milk samples using a selective media, mannitol salt agar (MSA). Suspect colonies of SA were further analyzed using biochemical tests. Polymerase chain reaction and sequencing techniques were used to confirm SA and detect sea, seb, sec, sed and see enterotoxin genes. Overall, potentially pathogenic S. aureus harboring enterotoxic genes were detected in 85 (14.09%, 95% CI: 11.55–17.1%) of the total milk samples. Genes encoding enterotoxins were detected in the S. aureus bacteria isolated from the milk samples. At least one type of S. aureus enterotoxin gene (SE) was detected in 74.11% (95% CI: 63.91–82.24%) of the 85 isolates. The most frequently encountered gene in the two counties was see (51; 60%, 95% CI: 49.73–69.76%) followed by sea (22; 25.88%, 95% CI: 17.76–36.09%) and sec (19; 22.35%, 95% CI: 14.8–32.29%). None of the isolates tested positive for sed. Overall, 21 of the 85 (24.7%, 95% CI: 16.76–34.83%) strains harbored more than one enterotoxin gene. More than half of the S. aureus isolates harbored at least one of the enterotoxin coding genes, indicating milk samples contaminated by S. aureus could have a high chance of causing staphylococcal food intoxication. Consumption of raw and sour milk in the region could increase the risk of staphylococcal food poisoning and pastoral communities in the region are therefore advised to consume pasteurized milk.

Livestock-wildlife interactions promote the transmission of a wide range of infectious diseases that constraint livestock production. We used a participatory appraisal approach to find out and rank infectious diseases of concern to pastoralists in a zone of intense wildlife-livestock interaction and another zone with limited interactions. Four villages were selected purposively in areas with intensive cattle-wildlife interactions (zone 1), and another two in areas with low to moderate cattle-wildlife interactions (zone 2). Data were collected in focus group discussions (FGDs) using participatory epidemiological methods (PE); each group had 8–13 participants. Results of impact matrix scoring from all sites indicated that malignant catarrhal fever (MCF), anthrax, foot and mouth disease (FMD), contagious bovine pleuropneumonia (CBPP), east coast fever (ECF) and African animal trypanosomiasis (ATT), in decreasing order, had the highest impact on livestock production. A Kruskal–Wallis test revealed a significant difference in FMD annual prevalence between cattle age groups (p 4 years (median score of 32.5, range, 10–50). FMD had the highest impact on milk production, but based on veterinary costs (treatment costs), it was ranked second to CBPP. The study provides information on disease priorities that occur in the target zones in Mara ecosystem and which the local pastoralists must consider when accessing key ecosystem services such as water and pasture. Electronic supplementary material The online version of this article (10.1007/s11250-018-01790-1) contains supplementary material, which is available to authorized users.

Brucellosis, caused by several species of the genus Brucella, is a zoonotic disease that affects humans and animal species worldwide. Information on the Brucella species circulating in different hosts in Kenya is largely unknown, thus limiting the adoption of targeted control strategies. This study was conducted in multi-host livestock populations in Kenya to detect the circulating Brucella species and assess evidence of host–pathogen associations. Serum samples were collected from 228 cattle, 162 goats, 158 sheep, 49 camels, and 257 humans from Narok and Marsabit counties in Kenya. Information on age, location and history of abortion or retained placenta were obtained for sampled livestock. Data on age, gender and location of residence were also collected for human participants. All samples were tested using genus level real-time PCR assays with primers specific for IS711 and bcsp31 targets for the detection of Brucella. All genus positive samples (positive for both targets) were further tested with a speciation assay for AlkB and BMEI1162 targets, specific for B. abortus and B. melitensis, respectively. Samples with adequate quantities aggregating to 577 were also tested with the Rose Bengal Test (RBT). A total of 199 (33.3%) livestock and 99 (38.5%) human samples tested positive for genus Brucella. Animal Brucella PCR positive status was positively predicted by RBT positive results (OR = 8.3, 95% CI 4.0–17.1). Humans aged 21–40 years had higher odds (OR = 2.8, 95% CI 1.2–6.6) of being Brucella PCR positive compared to the other age categories. The data on detection of different Brucella species indicates that B. abortus was detected more often in cattle (OR = 2.3, 95% CI 1.1–4.6) and camels (OR = 2.9, 95% CI 1.3–6.3), while B. melitensis was detected more in sheep (OR = 3.6, 95% CI 2.0–6.7) and goats (OR = 1.7, 95% CI 1.0–3.1). Both B. abortus and B. melitensis DNA were detected in humans and in multiple livestock host species, suggesting cross-transmission of these species among the different hosts. The detection of these two zoonotic Brucella species in humans further underpins the importance of One Health prevention strategies that target multiple host species, especially in the multi-host livestock populations.

The climate is changing, and such changes are projected to cause global increase in the prevalence and geographic ranges of infectious diseases such as anthrax. There is limited knowledge in the tropics with regards to expected impacts of climate change on anthrax outbreaks. We determined the future distribution of anthrax in Kenya with representative concentration pathways (RCP) 4.5 and 8.5 for year 2055. Ecological niche modelling (ENM) of boosted regression trees (BRT) was applied in predicting the potential geographic distribution of anthrax for current and future climatic conditions. The models were fitted with presence-only anthrax occurrences (n = 178) from historical archives (2011–2017), sporadic outbreak surveys (2017–2018), and active surveillance (2019–2020). The selected environmental variables in order of importance included rainfall of wettest month, mean precipitation (February, October, December, July), annual temperature range, temperature seasonality, length of longest dry season, potential evapotranspiration and slope. We found a general anthrax risk areal expansion i.e., current, 36,131 km2, RCP 4.5, 40,012 km2, and RCP 8.5, 39,835 km2. The distribution exhibited a northward shift from current to future. This prediction of the potential anthrax distribution under changing climates can inform anticipatory measures to mitigate future anthrax risk.

Background Anthrax is an important zoonotic disease in Kenya associated with high animal and public health burden and widespread socio-economic impacts. The disease occurs in sporadic outbreaks that involve livestock, wildlife, and humans, but knowledge on factors that affect the geographic distribution of these outbreaks is limited, challenging public health intervention planning. Methods Anthrax surveillance data reported in southern Kenya from 2011 to 2017 were modeled using a boosted regression trees (BRT) framework. An ensemble of 100 BRT experiments was developed using a variable set of 18 environmental covariates and 69 unique anthrax locations. Model performance was evaluated using AUC (area under the curve) ROC (receiver operating characteristics) curves. Results Cattle density, rainfall of wettest month, soil clay content, soil pH, soil organic carbon, length of longest dry season, vegetation index, temperature seasonality, in order, were identified as key variables for predicting environmental suitability for anthrax in the region. BRTs performed well with a mean AUC of 0.8. Areas highly suitable for anthrax were predicted predominantly in the southwestern region around the shared Kenya-Tanzania border and a belt through the regions and highlands in central Kenya. These suitable regions extend westwards to cover large areas in western highlands and the western regions around Lake Victoria and bordering Uganda. The entire eastern and lower-eastern regions towards the coastal region were predicted to have lower suitability for anthrax. Conclusion These modeling efforts identified areas of anthrax suitability across southern Kenya, including high and medium agricultural potential regions and wildlife parks, important for tourism and foreign exchange. These predictions are useful for policy makers in designing targeted surveillance and/or control interventions in Kenya. We thank the staff of Directorate of Veterinary Services under the Ministry of Agriculture, Livestock and Fisheries, for collecting and providing the anthrax historical occurrence data., Author summary Anthrax is a neglected zoonosis worldwide. In Kenya, outbreaks have been reported in wildlife, livestock, and humans, resulting in severe public health burden and socio-economic impacts. Because of this, anthrax is ranked as the highest priority disease in the country. To identify factors that influence the spatial distribution of the disease in Kenya, we analyzed surveillance on available anthrax outbreaks recorded in the southern half of the country. Areas predicted to be highly suitable for the disease were predominantly in the southwestern region around the shared Kenya-Tanzania border running as a belt through central regions and central highlands of Kenya. These suitability regions extend westwards to cover large areas in western highlands and the western regions around Lake Victoria and bordering Uganda. The entire eastern and lower-eastern regions towards the coastal region were predicted to have lower suitability for anthrax. Cattle density, rainfall of wettest month, soil clay content, soil pH, soil organic carbon, length of longest dry season, vegetation index and temperature seasonality were key variables predicting the distribution of anthrax in the region. The study generated a suitability map depicting geographical areas that can be targeted for risk-based surveillance and or control measures for the disease.

Brucella is a highly pathogenic bacteria endemic in Kenya, and in spite of its severity in humans, the highly inadequate Febrile Antigen Brucella Agglutination Test (FBAT) remains a primary tool for its diagnosis. Blood samples were collected from febrile patients in Kinna health center and screened by the local routine. Milk samples were purchased from local milk hawkers and analyzed for Brucella antibodies using the milk ring test (MRT). The MRT-positive milk was traced to farms, and lactating cattle were sampled for milk and blood. Milk was MRT-tested and the serum was analyzed using the Rose Bengal test (RBT) and iELISA. Available patient and farm samples were stored on FTA cards for qPCR analyses. Despite a limited sample size, our study, in line with previous reports, shows a low diagnostic sensitivity (67%) and specificity (40%) of FBAT when compared to qPCR. As many as 48% of the raw bulk cattle milk samples were MRT-positive for Brucella antibodies and 60% of cattle on three visited farms were IS711 qPCR-positive. This case-based One Health investigation confirms the suspected Brucella presence, suggesting a targeted vaccination at high-prevalence farms, urgent interventions on milk safety, and a re-evaluation of the diagnostic and treatment regimen.

Floods precipitate many infectious disease epidemics in humans and animals. These incidences are more prevalent in developing countries where about 80% of illnesses and deaths in humans are water related. This chapter identifies three categories of flood-borne infections based on how floods influence their occurrence patterns. The first category includes acute infections such as cholera and leptospirosis, caused by bacteria that are carried mechanically by water and are often ingested with water or food. These infections thrive in areas with high human population densities with poor sanitation. In these settings, floods enhance transmission of infectious agents between hosts. The second category is vector-borne infections such as malaria, Rift Valley fever, and schistosomiasis. They are transmitted by vectors that breed in inundated areas. Their epidemics often follow flood events by weeks or months depending on the duration of their development cycles. The last category is skin and eye infections that occur following direct contact with contaminated water. All these diseases can be controlled more effectively if the standard surveillance and control measures are integrated with nature-based solutions (NBS) for flood management. Examples the NBS that can be used include re-forestation, tree planting especially along streams, and development of green infrastructure in cities to enhance water retention, infiltration, and replenishment of groundwater.

An evaluation of emerging issues in One Health (OH) in Sub-Saharan Africa was undertaken to map the existing OH initiatives in Sub-Saharan African (SSA) countries. Desk review, expert opinions survey, limited interviews and wider consultations with selected OH stakeholders were conducted. The strengths, weaknesses, opportunities and threats to OH initiatives were identified. OH influence, interest and impacts were evaluated. One Health is transiting from multidisciplinary to transdisciplinary concepts and OH viewpoint should move from ‘proxy for zoonoses’, to include issues of climate change, nutrition and food safety, social sciences, geography, policy and planning, economics, welfare and well-being, antimicrobial resistance (AMR), vector-borne diseases, toxicosis and pesticides issues. While the identified major strengths should be boosted, the weaknesses should be addressed.OH Networks in SSA were spatially and temporally spread across SSA and stakeholders were classified as key, latent, marginal and OH defenders. Imbalance in stakeholders’ representation led to hesitation in buying-in from stakeholders who are outside the main networks. Theory of change, monitoring and evaluation frameworks, and tools to standardized evaluation of OH policies is needed for sustained future of OH and the future OH engagement should be outputs and outcomes-driven and not activity-driven.National roadmap for OH implementation and institutionalization is necessary and proofs of concepts in OH should be verified and scaled-up. Dependence on external funding is unsustainable and must be addressed. Necessary policy and legal instrument to support OH nationally and sub-nationally should be implemented taking cognizance of contemporary issues like urbanization, endemic poverty and other emerging issues. Utilizing current technologies and OH approach to address ongoing pandemic of COVID-19 and other emerging diseases is desirable. Finally, OH implementation should be anticipatory and not reactive to significantly benefit budgeting and contain disease outbreaks in animal sources before the risk of spillover to human can be envisaged.

Rift Valley fever (RVF) is a vector-borne disease transmitted by a broad spectrum of mosquito species, especially Aedes and Culex genus, to animals (domestic and wild ruminants and camels) and humans. Rift Valley fever is endemic in sub-Saharan Africa and in the Arabian Peninsula, with periodic epidemics characterised by 5–15 years of inter-epizootic periods. In the last two decades, RVF was notified in new African regions (e.g. Sahel), RVF epidemics occurred more frequently and low-level enzootic virus circulation has been demonstrated in livestock in various areas. Recent outbreaks in a French overseas department and some seropositive cases detected in Turkey, Tunisia and Libya raised the attention of the EU for a possible incursion into neighbouring countries. The movement of live animals is the most important pathway for RVF spread from the African endemic areas to North Africa and the Middle East. The movement of infected animals and infected vectors when shipped by flights, containers or road transport is considered as other plausible pathways of introduction into Europe. The overall risk of introduction of RVF into EU through the movement of infected animals is very low in all the EU regions and in all MSs (less than one epidemic every 500 years), given the strict EU animal import policy. The same level of risk of introduction in all the EU regions was estimated also considering the movement of infected vectors, with the highest level for Belgium, Greece, Malta, the Netherlands (one epidemic every 228–700 years), mainly linked to the number of connections by air and sea transports with African RVF infected countries. Although the EU territory does not seem to be directly exposed to an imminent risk of RVFV introduction, the risk of further spread into countries neighbouring the EU and the risks of possible introduction of infected vectors, suggest that EU authorities need to strengthen their surveillance and response capacities, as well as the collaboration with North African and Middle Eastern countries. info:eu-repo/semantics/publishedVersion

Background The seroprevalence of brucellosis among nomadic pastoralists and their livestock in arid lands is reported to be over10-fold higher than non-pastoralists farmers and their livestock in Kenya. Here, we compared the seroprevalence of nomadic pastoralists and mixed farming with their knowledge of the disease and high-risk practices associated with brucellosis infection. Methods Across-sectional study was conducted in two counties - Kiambu County where farmers primarily practice smallholder livestock production and crop farming, and Marsabit County where farmers practice nomadic pastoral livestock production. Stratified random sampling was applied, in which sublocations were initially selected based on predominant livestock production system, before selecting households using randomly generated geographical coordinates. In each household, up to three persons aged 5 years and above were randomly selected, consented, and tested for Brucella spp IgG antibodies. A structured questionnaire was administered to the household head and selected individuals on disease knowledge and risky practices among the pastoralists and mixed farmers compared. Multivariable mixed effects logistic regression model was used to assess independent practices associated with human Brucella spp. IgG seropositivity. Results While the majority (74%) of pastoralist households had little to no formal education when compared to mixed (8%), over 70% of all households (pastoralists and mixed farmers) had heard of brucellosis and mentioned its clinical presentation in humans. However, fewer than 30% of all participants (pastoralists and mixed farmers) knew how brucellosis is transmitted between animals and humans or how its transmission can be prevented. Despite their comparable knowledge, significantly more seropositive pastoralists compared to mixed farmers engaged in risky practices including consuming unboiled milk (79.5% vs 1.7%, p p < 0.001), assisting in animal birth (43.0% vs 9.3%, p < 0.001), and handling raw hides (30.6% vs 5.5%, p < 0.001)., Conclusion Nomadic pastoralists are more likely to engage in risky practices that promote Brucella Infection, probably because of their occupation and culture, despite having significant knowledge of the disease.

Environmental modifications disturb the equilibrium of mosquito populations, altering the risk of mosquito-borne diseases. Mosquito distribution, diversity, and bloodmeal sources were examined to compare Rift Valley fever (RVF) risk among irrigated, riverine, and pastoral ecosystems in Bura, Tana River County, Kenya, between September 2014 and June 2015. Thirty-eight households and 21 irrigation fields were selected for the study. Mosquitoes were trapped with carbon dioxide-impregnated CDC traps, one trap per household and three traps per irrigated field, and morphologically identified using taxonomic keys. Host DNA was extracted from engorged females and cytochrome b genes amplified by PCR to identify sources of bloodmeals. A total of 21,015 mosquitoes were collected; 5742 within households in the 3 ecosystems and 15,273 within irrigated fields. Mosquitoes collected within irrigated fields belonged to 8 genera and 37 species, while those from households within the irrigation scheme belonged to 6 genera and 29 species. Collections from riverine and pastoral households belonged to five and four genera, respectively. The most abundant genera in the irrigated fields were Aedes (21%) and Mansonia (22%), while Anopheles (43%) was the most abundant within households. Most mosquitoes in riverine and pastoral households belonged to Anopheles (76%) and Aedes (65%) genera, respectively. Seasonal variation driven by rainfall was evidenced by spikes in mosquito numbers within irrigated and riverine ecosystems. Host species identification revealed that goats and humans were the main sources of bloodmeal. There was an overall increase in mosquito abundance and diversity as a result of the presence of the irrigated ecosystem in this county, and an increased availability of highly RVF-susceptible hosts as a result of the establishment and concentration of residential areas, promoting potential vector-host contacts. These results highlight the impact of anthropogenic changes on mosquito ecology, potentially heightening the risk of transmission and maintenance of RVF in this region.

Rift Valley fever (RVF) virus is associated with recurring disease epidemics among livestock and humans in sub-Saharan Africa and Middle East, where the virus is endemic in certain ecosystems. Since the mechanisms of its maintenance during the long (4–10 year) inter-epidemic periods (IEPs) are poorly understood, we reviewed the latest findings that shed light on this, and identify ecological factors unique to the endemic areas. Recent studies reported acute RVF cases in humans and livestock, and significant disease prevalence during IEPs, indicating low-level cycling of the virus in wildlife, livestock, and humans. Niche modeling identified ecological factors that seem important in supporting the mosquito vector and virus maintenance, and the occurrence of RVF epidemics. The virus is primarily maintained by circulating at low levels among wildlife, livestock, and humans, transmitted by mosquito vectors in ecosystems characterized by low annual rainfall during non-El Nino climatic periods and certain soil types. The findings indicate that prolonged survival of the virus in mosquito eggs, suggested in previous studies, may not be required for its maintenance.

Rift Valley fever (RVF) is an acute mosquito-borne viral zoonosis whose outbreaks are often associated with prolonged rainfall and flooding, during which large numbers of vectors emerge. Recent studies into the inter-epidemic maintenance of RVF virus (RVFV) suggest that both vertical transmission in vectors and direct transmission between hosts act in combination with predisposing factors for persistence of the virus. A comparative longitudinal survey was carried out in Tana River County, Kenya, in irrigated, riverine and pastoral ecosystems from September 2014-June 2015. The objectives were to investigate the possibility of low-level RVFV transmission in these ecosystems during an inter-epidemic period (IEP), examine variations in RVFV seroprevalence in sheep and goats and determine the risk factors for transmission. Three hundred and sixteen small ruminants were selected and tested for immunoglobulin G antibodies against RVFV nucleoprotein using a competitive ELISA during six visits. Data on potential risk factors were also captured. Inter-epidemic RVFV transmission was evidenced by 15 seroconversions within the irrigated and riverine villages. The number of seroconversions was not significantly different (OR = 0.66, CI = 0.19-2.17, p = .59) between irrigated and riverine areas. No seroconversions were detected in the pastoral ecosystem. This study highlights the increased risk of inter-epidemic RVFV transmission posed by irrigation, through provision of necessary environmental conditions that enable vectors access to more breeding grounds, resting places and shade, which favour their breeding and survival.

The planet's mean air and ocean temperatures have been rising over the last century because of increasing greenhouse gas (GHG) emissions. These changes have substantial effects on the epidemiology of infectious diseases. We describe direct and indirect processes linking climate change and infectious diseases in livestock with reference to specific case studies. Some of the studies are used to show a positive association between temperature and expansion of the geographical ranges of arthropod vectors (e.g. Culicoides imicola, which transmits bluetongue virus) while others are used to illustrate an opposite trend (e.g. tsetse flies that transmit a range of trypanosome parasites in sub-Saharan Africa). We further describe a positive association between extreme events: droughts and El Niño/southern oscillation (ENSO) weather patterns and Rift Valley fever outbreaks in East Africa and some adaptation practices used to mitigate the impacts of climate change that may increase risk of exposure to infectious pathogens. We conclude by outlining mitigation and adaptation measures that can be used specifically in the livestock sector to minimize the impacts of climate change-associated livestock diseases.

Rift Valley fever (RVF) is a vector-borne zoonotic disease caused by phlebovirus in the family Bunyaviridae. In Kenya, major outbreaks occurred in 1997-1998 and 2006-2007 leading to human deaths, huge economic losses because of livestock morbidity, mortality, and restrictions on livestock trade.This study was conducted to determine RVF seroprevalence in cattle, sheep, and goats during an interepidemic period in Garissa County in Kenya.In July 2013, we performed a cross-sectional survey and sampled 370 ruminants from eight RVF-prone areas of Garissa County. Rift Valley fever virus (RVFV) antibodies were detected using a multispecies competitive enzyme-linked immunosorbent assay. Mixed effect logistic regression models were used to determine the association between RVF seropositivity and species, sex, age, and location of the animals.A total of 271 goats, 87 sheep, and 12 cattle were sampled and the overall immunoglobulin G seroprevalence was 27.6% (95% CI [23-32.1]). Sheep, cattle, and goats had seroprevalences of 32.2% (95% CI [20.6-31]), 33.3% (95% CI [6.7-60]), and 25.8% (95% CI [22.4-42]), respectively. Seropositivity in males was 31.8% (95% CI [22.2-31.8]), whereas that of females was 27% (95% CI [18.1-45.6]).The high seroprevalence suggests RVFV circulation in domestic ruminants in Garissa and may be indicative of a subclinal infection. These findings provide evidence of RVF disease status that will assist decision-makers to flag areas of high risk of RVF outbreaks and prioritize the implementation of timely and cost-effective vaccination programs.

Rift Valley fever (RVF) is a zoonotic disease of great public health and economic importance transmitted by mosquitoes. The main method of preventing the disease is vaccination of susceptible livestock before outbreaks occur. Studies on RVF vaccines have focused on the production processes, safety, and efficacy standards but those on uptake and adoption levels are rare. This study sought to understand the barriers faced by men and women farmers in the uptake of livestock vaccines to inform strategies for optimizing the use of vaccines against RVF in East Africa. The cross-sectional qualitative study utilized the pairwise ranking technique in sex disaggregated focus group discussions to identify and rank these barriers. Results indicate that men and women farmers experience barriers to vaccine uptake differentially. The barriers include the direct and indirect cost of vaccines, distances to vaccination points, availability of vaccination crushes, intra-household decision making processes and availability of information on vaccination campaigns. The study concludes that vaccine provision does not guarantee uptake at the community level. Hence, these barriers should be considered while designing vaccination strategies to enhance community uptake because vaccine uptake is a complex process which requires buy-in from men and women farmers, veterinary departments, county/district and national governments, and vaccine producers.

BackgroundCystic hydatidosis (CH), a neglected parasitic zoonosis, is endemic in many parts of Kenya and could be spread along livestock marketing chains. Poor knowledge, attitude and practices (KAP) enables this spread in remote areas with inadequate public health services. We estimated prevalence, identified possible origin of CH to Busia, Kenya and assessed KAP among cattle owners and abattoir workers.Methods and Principal FindingsWe conducted a cross-sectional study on slaughtered livestock and interviewed their owners and abattoir workers in Busia in May–June 2018. We used visual observation, palpation and incision to identify cysts. Polymerase chain reaction (PCR) was used for confirmatory diagnosis. Epi Info 7 was used to calculate descriptive and associative statistics. Of 302 carcasses inspected, cysts were visualized in nine (2.98%, 95% Confidence Interval (CI): 1.46–5.78). Fourteen samples were collected and 13 (92.86%) were positive on PCR (sensitivity=92%, specificity=95%). All carcasses with cysts were from West Pokot County, which borders Busia to the north. We interviewed 310 participants: 260 were males (83.87%, 95% CI: 79.19 – 87.69); median age was 41 years (range=21-69). Dogs were kept by 221 (71.99%, 95% CI: 66.55 – 76.87), of which 83 (37.56%, 95% CI: 28.33 – 48.52) improperly disposed of dog faeces. Home slaughtering was practiced by 196 (63.23%, 95% CI: 58.78-69.80), of which 115 (58.67%, 95% CI: 51.44-65.64) were not inspected and 85 (43.37%, 95% CI: 36.32-50.62) fed raw organs to dogs. Adequate knowledge was associated with butcher ownership (P-value = 0.002), age ≥35 years (P-value = 0.002) and higher literacy level (P-value Conclusions and SignificanceThere is non-negligible risk of CH in Busia communities which might worsen with time given that the county is connected to endemic areas through livestock trade. Poor KAP by the people on the disease calls for need to implement information, education and communication campaigns to improve KAP on CH in the area.Author summaryCystic hydatidosis is a globally neglected parasitic zoonosis which is endemic in many parts of the world including Kenya. It is majorly a problem among pastoral communities where there is close contact between human, livestock and dogs. Busia County, in Western Kenya is part of a livestock marketing chain between Kenya and Uganda. Animals from high endemic regions in Uganda and Kenya can easily spread the parasite to Busia through improper disposal of their infested organs. Non-pastoral communities like Busia may not have much cumulative experience about the disease though their practices may contribute to the perpetuation of the parasite in their environment. The parasite is gradually spreading to new areas and it is very important to the public health players in Kenya to take action so as to prevent further spread of this disease. Findings from this study show that the disease is no longer limited to pastoral communities only. There is need for the implementation of information, education and communication campaigns to improve the knowledge, attitude and practices of Busia community and other non-endemic regions on the disease.

Introduction Brucellosis is an important zoonotic disease in Kenya, and identifying the bacteria in milk is important in assessing the risk of exposure in people. Methods A cross-sectional study that involved 175 households was implemented in the pastoral counties of Marsabit and Isiolo in Kenya. Pooled milk samples (n = 164) were collected at the household level, and another 372 were collected from domesticated lactating animals (312 goats, 7 sheep, 50 cattle and 3 camels). Real-time polymerase chain reaction (qPCR) testing of the milk samples was performed to identify Brucella species. Brucella anti-LPS IgG antibodies were also detected in bovine milk samples using an indirect enzyme-linked immunosorbent assay (ELISA). Results Based on the qPCR, the prevalence of the pathogen at the animal level (considering samples from individual animals) was 2.4% (95% confidence interval (CI) 1.1–4.5) and 3.0% (CI: 1.0–7.0) in pooled samples. All 14 samples found positive by qPCR were from goats, with 10 contaminated with B. abortus and 4 with B. melitensis. The Brucella spp. antibody prevalence in bovine milk using the milk ELISA was 26.0% (95% CI: 14.6–40.3) in individual animal samples and 46.3% (95% CI: 30.7–62.6) in pooled samples. Conclusion The study is the first in Kenya to test for Brucella spp. directly from milk using qPCR without culturing for the bacteria. It also detected B. abortus in goats, suggesting transmission of brucellosis between cattle and goats. The high prevalence of Brucella spp. is a significant public health risk, and there is a need for intervention strategies necessary in the study area.

Climate change influences the occurrence and transmission of a wide range of livestock diseases through multiple pathways. Diseases caused by pathogens that spent part of their life cycle outside the host (e.g. in vectors or the environment) are more sensitive in this regard, compared to those caused by obligate pathogens. In this chapter, we use two well-studied vector-borne diseases—Rift Valley fever (RVF) and tick-borne diseases (TBDs)—as case studies to describe direct pathways through which climate change influences infectious disease-risk in East and southern Africa. The first case study demonstrates that changes in the distribution and frequency of above-normal precipitation increases the frequency of RVF epidemics. The second case study suggests that an increase in temperature would cause shifts in the spatial distribution of TBDs, with cooler and wetter areas expected to experience heightened risk with climate change. These diseases already cause severe losses in agricultural productivity, food security and socio-economic development wherever they occur, and an increase in their incidence or geographical coverage would intensify these losses. We further illustrate some of the control measures that can be used to manage these diseases and recommend that more research should be done to better understand the impacts of climate change on livestock diseases as well as on the effectiveness of the available intervention measures.

Camels are increasingly becoming the livestock of choice for pastoralists reeling from effects of climate change in semi-arid and arid parts of Kenya. As the population of camels rises, better understanding of their role in the epidemiology of zoonotic diseases in Kenya is a public health priority. Rift Valley fever (RVF), brucellosis and Q fever are three of the top priority diseases in the country but the involvement of camels in the transmission dynamics of these diseases is poorly understood. We analyzed 120 camel serum samples from northern Kenya to establish seropositivity rates of the three pathogens and to characterize the infecting Brucella species using molecular assays. We found seropositivity of 24.2% (95% confidence interval [CI]: 16.5–31.8%) for Brucella, 20.8% (95% CI: 13.6–28.1%) and 14.2% (95% CI: 7.9–20.4%) for Coxiella burnetii and Rift valley fever virus respectively. We found 27.5% (95% CI: 19.5–35.5%) of the animals were seropositive for at least one pathogen and 13.3% (95% CI: 7.2–19.4%) were seropositive for at least two pathogens. B. melitensis was the only Brucella spp. detected. The high sero-positivity rates are indicative of the endemicity of these pathogens among camel populations and the possible role the species has in the epidemiology of zoonotic diseases. Considering the strong association between human infection and contact with livestock for most zoonotic infections in Kenya, there is immediate need to conduct further research to determine the role of camels in transmission of these zoonoses to other livestock species and humans. This information will be useful for designing more effective surveillance systems and intervention measures., Author summary Dromedary camels are well adapted to the arid and semi-arid environment that makes up about 80% of Kenya’s landmass. As such, camels play an important role in the socio-economic wellbeing and food security of pastoralists in the country. However, the species remains relatively neglected in scientific research, one of the main reasons being camels are mostly found in remote, low-income, arid regions of Africa and Asia. We carried out a study to determine the levels of exposure of camels in northern Kenya to Brucella spp., Coxiella burnetii and Rift Valley fever virus, three priority zoonotic pathogens in the country. We found high levels of exposure to the three pathogens, indicating the important role camels might play in the epidemiology of the zoonotic diseases in humans and other livestock. Based on the study findings, we argue for the immediate need for investments in disease surveillance and control strategies for priority zoonotic disease in camels in Kenya.

Dromedaries in Africa and elsewhere carry the Middle East respiratory syndrome coronavirus (MERS-CoV). To search for evidence of autochthonous MERS-CoV infection in humans, we tested archived serum from livestock handlers in Kenya for MERS-CoV antibodies. Serologic evidence of infection was confirmed for 2 persons sampled in 2013 and 2014.

Global risks of zoonotic disease are high on policy agendas. Increasingly, Africa is seen as a ‘hotspot’, with likely disease spillovers from animals to humans. This paper explores the social dynamics of disease exposure, demonstrating how risks are not generalised, but are related to occupation, gender, class and other dimensions of social difference. Through case studies of Lassa Fever in Sierra Leone, Henipah virus in Ghana, Rift Valley Fever in Kenya and Trypanosomiasis in Zimbabwe, the paper proposes a social difference space–time framework to assist the understanding of and response to zoonotic diseases within a ‘One Health’ approach.

A cross-sectional study was carried out to determine foot-and-mouth disease (FMD) seroprevalence and identify risk factors of exposure among cattle herds raised in three zones with different types of land use and progressively distant from the Maasai Mara National Reserve (MMNR) boundary. We selected five villages purposively; two in zone 1 (area20 km from the MMNR), another two in zone 2 (area between 20-40 km away from the MMNR) and one in zone 3 (area40 km away from the MMNR). A total of 1170 cattle sera were collected from 390 herds in all the zones and tested for antibodies against the non-structural proteins (NSPs) of FMD virus (FMDV) using two 3ABC-based Enzyme-Linked Immunosorbent Assay ELISA kits. All sera samples were also screened for serotype-specific antibodies using Solid Phase Competitive ELISA (SPCE) kits (IZSLER, Italy). We targeted FMDV serotypes A, O, South African Territory [SAT] 1 and SAT 2, known to be endemic in East Africa including Kenya. Data on putative risk factors for FMD seropositivity in cattle were collected using a questionnaire. The overall apparent animal-level FMD seroprevalence based on the parallel comparison of the two anti-NSPs ELISA kits was 83.8 % (95 % CI; 81.8-85.9), and differed significantly across zones. Zone 1 had a higher seroprevalence than zones 2 and 3 (χ

Objectives Brucellosis is caused by bacteria from the genus Brucella which infect human and domestic animals as well as wildlife. The Maasai Mara National Reserve has vast populations of wild ruminants such as buffaloes and wildebeest which could contribute to the risk of brucellosis in livestock, and the surrounding pastoralist communities grazing cattle in and around the reserve may be exposed to a higher risk of zoonotic diseases like brucellosis due to the close contact with livestock. In this study, cattle from three villages at varying distance from the reserve, were screened for antibodies against Brucella abortus. Results In total, 12.44% of 225 sampled animals were seropositive, with more females (15%) infected than males (5%). Seroprevalence was higher in livestock closer to Maasai Mara with the cattle in the village Mara Rianta having an odds ratio of 7.03 compared to Endoinyo Narasha further away (95% CI 1.4–11.1, p = 0.003), suggesting that a closer contact with wildlife may increase the circulation of infectious diseases between livestock and wildlife. Symptoms consistent with brucellosis were reported to occur in both humans and animals, and we thus conclude that brucellosis may be an important problem, both for the health and the economy. Electronic supplementary material The online version of this article (10.1186/s13104-017-2941-x) contains supplementary material, which is available to authorized users.

Rift Valley fever is a severe disease affecting both humans and animals. The Rift Valley fever virus can be transmitted by body fluids, and the most common way for humans to get infected is from animals. The virus is also vector-borne and can be transmitted by many species of mosquitoes. As with other vector-borne diseases, the epidemiology may vary in response to environmental changes. Here the effects of climate and land use changes on Rift Valley fever, as well as on other vector-borne diseases, are discussed. The effect of irrigation in East Africa on inter-epidemic transmission of RVF is discussed in greater detail, followed by recommendations for future research and actions.

MET targeted therapies are under clinical evaluation for non-small-cell lung cancer (NSCLC) patients. Tyrosine kinase inhibitors (TKI) against MET have varying degrees of specificity. Tivantinib (ARQ 197) is reported to be a non-ATP competitive selective MET inhibitor. We aimed to compare the activity of tivantinib to established MET TKIs in a panel of NSCLC cell lines characterized by their MET dependency and by different relevant genotypes. A549, H3122, PC9 and HCC827, their respective resistant clones PC9 GR4 and HCC827 GR6 and the MET amplified cell lines H1993 and EBC-1 were treated in vitro with tivantinib, crizotinib or PHA-665752. Crizotinib and PHA-665752 showed growth inhibition restricted to MET dependent cell lines. The pattern of activity was related to MET inhibition and downstream signaling inhibition of AKT and ERK1/2, resulting in G0/G1 cycle arrest and apoptosis. In contrast, tivantinib possessed more potent anti-proliferative activity that was not restricted to only MET dependent cell lines. Tivantinib did not inhibit cellular MET activity or phosphorylation of downstream signaling proteins AKT or ERK1/2 in either MET dependent or independent cell lines. Cell cycle analysis demonstrated that tivantinib induced a G2/M arrest and induced apoptosis. Tivantinib but not crizotinib effected microtubule dynamics, disrupting mitotic spindles by a mechanism consistent with it functioning as a microtubule depolymerizer. Tivantinib activity is independent of MET signaling in NSCLC and suggests alternative mechanisms of action that should be considered when interpreting the results from on-going clinical studies.

Background Brucella spp. is a zoonotic bacterial agent of high public health and socio-economic importance. It infects many species of animals including wildlife, and people may get exposed through direct contact with an infected animal or consumption of raw or undercooked animal products. A linked livestock-human cross-sectional study to determine seroprevalences and risk factors of brucellosis in livestock and humans was designed. Estimates were made for intra-cluster correlation coefficients (ICCs) for these observations at the household and village levels. Methodology The study was implemented in Garissa (specifically Ijara and Sangailu areas) and Tana River (Bura and Hola) counties. A household was the unit of analysis and the sample size was derived using the standard procedures. Serum samples were obtained from selected livestock and people from randomly selected households. Humans were sampled in both counties, while livestock could be sampled only in Tana River County. Samples obtained were screened for anti-Brucella IgG antibodies using ELISA kits. Data were analyzed using generalized linear mixed effects logistic regression models with the household (herd) and village being used as random effects. Results The overall Brucella spp. seroprevalences were 3.47% (95% confidence interval [CI]: 2.72–4.36%) and 35.81% (95% CI: 32.87–38.84) in livestock and humans, respectively. In livestock, older animals and those sampled in Hola had significantly higher seroprevalences than younger ones or those sampled in Bura. Herd and village random effects were significant and ICC estimates associated with these variables were 0.40 (95% CI: 0.22–0.60) and 0.24 (95% CI: 0.08–0.52), respectively. In humans, Brucella spp. seroprevalence was significantly higher in older people, males, and people who lived in pastoral areas than younger ones, females or those who lived in irrigated or riverine areas. People from households that had at least one seropositive animal were 3.35 (95% CI: 1.51–7.41) times more likely to be seropositive compared to those that did not. Human exposures significantly clustered at the household level; the ICC estimate obtained was 0.21 (95% CI: 0.06–0.52). Conclusion The presence of a Brucella spp.-seropositive animal in a household significantly increased the odds of Brucella spp. seropositivity in humans in that household. Exposure to Brucella spp. of both livestock and humans clustered significantly at the household level. This suggests that risk-based surveillance measures, guided by locations of primary cases reported, either in humans or livestock, can be used to detect Brucella spp. infections in livestock or humans, respectively., Author summary Brucellosis is an important zoonotic disease that primarily affects livestock and wildlife. In humans, the disease is characterized by prolonged fever, body aches, joint pains and weakness, while in livestock, the disease mainly causes abortions and infertility. We carried out a study in northeastern Kenya (Garissa and Tana River Counties) to identify factors that affect the distribution of the disease in people and livestock. Livestock and people from randomly selected households were recruited and serum samples were obtained and screened using ELISA kits for Brucella IgG antibodies as a measure to determine the level of exposure to Brucella spp. Data obtained were analyzed using mixed effects logistic regression models. Results obtained show that human and animal Brucella spp seroprevalences cluster at the household level. The odds of exposure in humans were at least three times higher in households that had at least one seropositive animal compared to those that had not. These results can be used to design risk-based surveillance systems where each Brucella spp. infection identified in livestock or humans could signal potential locations of additional brucellosis cases in humans and animals.

Background The impacts of vaccination on the transmission of Rift Valley fever virus (RVFV) have not been evaluated. We have developed a RVFV transmission model comprising two hosts—cattle as a separate host and sheep and goats as one combined host (herein after referred to as sheep)—and two vectors—Aedes species (spp) and Culex spp—and used it to predict the impacts of: (1) reactive vaccination implemented at various levels of coverage at pre-determined time points, (2) targeted vaccination involving either of the two host species, and (3) a periodic vaccination implemented biannually or annually before an outbreak. Methodology/Principal Findings The model comprises coupled vector and host modules where the dynamics of vectors and hosts are described using a system of difference equations. Vector populations are structured into egg, larva, pupa and adult stages and the latter stage is further categorized into three infection categories: susceptible, exposed and infectious mosquitoes. The survival rates of the immature stages (egg, larva and pupa) are dependent on rainfall densities extracted from the Tropical Rainfall Measuring Mission (TRMM) for a Rift Valley fever (RVF) endemic site in Kenya over a period of 1827 days. The host populations are structured into four age classes comprising young, weaners, yearlings and adults and four infection categories including susceptible, exposed, infectious, and immune categories. The model reproduces the 2006/2007 RVF outbreak reported in empirical surveys in the target area and other seasonal transmission events that are perceived to occur during the wet seasons. Mass reactive vaccination strategies greatly reduce the potential for a major outbreak. The results also suggest that the effectiveness of vaccination can be enhanced by increasing the vaccination coverage, targeting vaccination on cattle given that this species plays a major role in the transmission of the virus, and using both periodic and reactive vaccination strategies. Conclusion/Significance Reactive vaccination can be effective in mitigating the impacts of RVF outbreaks but practically, it is not always possible to have this measure implemented satisfactorily due to the rapid onset and evolution of RVF epidemics. This analysis demonstrates that both periodic and reactive vaccination ought to be used strategically to effectively control the disease., Author Summary Evaluation of the relative impacts of RVF vaccination has not been previously carried out. We present a model that simulates RVFV transmission between two livestock hosts (cattle as a separate host and sheep referring to both sheep and goats) and two mosquito species (Aedes and Culex species). We then apply the model to evaluate policy-relevant impacts of vaccinating (1) different proportions of animals at different times to the simulated outbreak, (2) either of the host species, and (3) different proportions of animals in a periodic biannual or annual vaccination preventative strategy. Vector population growth is dependent on rainfall extracted from the Tropical Rainfall Measuring Mission (TRMM) for an RVF endemic site in Kenya over a period of 1827 days. The model reproduces the 2006/2007 RVF outbreak reported in empirical surveys in the target area and other seasonal transmission events that occur during the wet seasons. Consistent with anecdotal evidence, mass livestock vaccination can greatly reduce the potential for a major outbreak. The model predicts that the effectiveness can be improved by increasing the proportion of vaccinated animals, targeting vaccination against cattle and strategically augmenting periodic preventative strategies with reactive strategies once a RVF outbreak is predicted.

Background Malaria, a disease caused by protozoan parasites of the genus Plasmodium and transmitted by female anopheline mosquitoes, is a major cause of morbidity, mortality and loss in productivity in humans. Baringo County is prone to seasonal transmissions of malaria mostly in the rainy seasons. Methods This cross-sectional study used a mixed methods approach to collect data on knowledge and lay management of malaria. A questionnaire survey was administered to 560 respondents while qualitative data was collected through 20 focus group discussions in four ecological zones covering Baringo North, Baringo South and Marigat sub-Counties of Baringo County. Analyses were done through summary and inferential statistics for quantitative data and content analysis for qualitative data. Results The study communities were knowledgeable of malaria signs, symptoms, cause and seasonality but this biomedical knowledge co-existed with other local perceptions. This knowledge, however, did not influence their first (p = 0.77) or second choice treatments (p = 0.49) and compliance to medication (p = 0.84). Up to 88 % of respondents reported having suffered from malaria. At the onset of a suspected malaria case community members reported the following: 28.9 % visited a health facility, 37.2 % used analgesics, 26.6 % herbal treatments, 2.2 % remnant malaria medicines, 2.2 % over the counter malaria medicines, 1 % traditional healers and 1.8 % other treatments. Nearly all respondents (97.8 %) reported visiting a health facility for subsequent treatments. Herbal treatments comprised of infusions and decoctions derived from roots, barks and leaves of plants believed to have medicinal value. Compliance to conventional malaria treatment regime was, however, identified as a challenge in malaria management. Quick relief from symptoms, undesirable qualities like drug bitterness and bad smell, undesirable side-effects, such as nausea and long regimen of treatment were some of the contributors to non-compliance. Men and women exhibited different health-seeking behaviours based on the cultural expectations of masculinity, femininity, gender roles and acceptability of health services. Conclusions While knowledge of malaria is important in identifying the disease, it does not necessarily lead to good management practice. Treatment-seeking behaviour is also influenced by perceived cause, severity of disease, timing, anticipated cost of seeking treatment and gender, besides the availability of both traditional and conventional medicines.

Background This study was conducted in Bura irrigation scheme in Tana River County and the pastoral area in Ijara, Garissa County in the eastern Kenya to establish the knowledge, attitude and practices on malaria transmission, control and management, and determine malaria prevalence and the associated risk factors. Methods A cross sectional survey design that involved 493 randomly selected people from 334 households was used between November and December 2013. All the randomly selected people were screened for malaria parasites using rapid diagnostic test (RDT)—Carestart™ malaria HRP2 (pf) kit. A questionnaire was administered to determine potential risk factors and perceptions on malaria exposure within a period of 2 months prior to the survey. Two logistic regression models were fitted to the data; one used the RDT results while the other used data from the questionnaire survey. Results Using RDT, the prevalence of malaria was 4.68 % (95 % CI: 1.48–7.88 %) and 0.31 % (−0.30 to 0.92 %) in irrigated and non-irrigated areas, respectively. From the questionnaires, 14.62 % (9.27–19.97 %) and 23.91 % (19.23–28.60 %) of the participants perceived to have had malaria in the irrigated and pastoral areas, respectively. The main malaria control measure was the use of bed nets: average of three nets per household in Bura irrigation scheme and one in Ijara. Artemether–lumefantrine was the main drug of choice mainly in the irrigated area while sulfadoxine–pyrimethamine was likely to be used in the non-irrigated area. Households located >5 km from the nearest health facility had higher prevalence of Plasmodium infection than those located ≤5 km. Conclusion The residents of Bura irrigation scheme were more likely to be infected compared to those living in the non-irrigated area of Ijara. However, those in the non-irrigated area were more likely to be treated or use over-the-counter medication for perceived malaria illnesses compared to those in the irrigated area. There is a need, therefore, to formulate effective ways of managing malaria especially in irrigated areas and build capacity on differential diagnosis for malaria, especially in the pastoral areas.

Background West Nile fever virus is a zoonotic arboviral infection maintained in a sylvatic cycle involving mosquito vectors and birds. It is one the arboviruses whose geographical range is expanding because of climate and land use changes that enhance the densities of mosquitoes and promote mosquito-bird-human interactions. We carried out a survey to determine the reservoirs of WNV among wild birds in Tana River and Garissa counties, Kenya. Methods Blood samples were obtained from 361 randomly trapped wild birds. Using real-time polymerase chain reaction (PCR), all samples were screened for WNV using gene specific primer sets amplifying a portion of the E region of the genome encoding the envelope protein. Results Sixty five (65) out of 361 birds screened tested positive for WNV on real-time PCR assay. Sequencing of the selected positive samples reveals that the isolated WNV were most closely related to strains isolated from China (2011). A regression analysis indicated that sampling location influenced the occurrence of WNV while species, age, weight and sex of the birds did not have any effect. Conclusions This study provides baseline information on the existing circulation of WNV in this region among wild bird reservoirs that could spill over to the human population and points to the need for implementation of surveillance programs to map the distribution of the virus among reservoirs. Awareness creation about West Nile fever in this region is important to improve its detection and management. Electronic supplementary material The online version of this article (doi:10.1186/s12879-016-2019-8) contains supplementary material, which is available to authorized users.

BACKGROUND:To-date, Rift Valley fever (RVF) outbreaks have occurred in 38 of the 69 administrative districts in Kenya. Using surveillance records collected between 1951 and 2007, we determined the risk of exposure and outcome of an RVF outbreak, examined the ecological and climatic factors associated with the outbreaks, and used these data to develop an RVF risk map for Kenya. METHODS:Exposure to RVF was evaluated as the proportion of the total outbreak years that each district was involved in prior epizootics, whereas risk of outcome was assessed as severity of observed disease in humans and animals for each district. A probability-impact weighted score (1 to 9) of the combined exposure and outcome risks was used to classify a district as high (score ≥ 5) or medium (score ≥2

The authors characterised sources of early warning messages about occurrences of Rift Valley fever (RVF) and examined the response measures that were used by the Department of Veterinary Services (DVS) to manage the 2006-2007 RVF outbreaks in Kenya. The study was conducted between November 2009 and March 2010 and it included national, provincial and district veterinary officers who were involved in the management of the outbreak. Structured questionnaires were used to collect the data. Although the majority of the respondents reported having limited capacity to implement response measures, they perceived that the measures implemented were effective. Vaccination, movement control and market closures were the main response measures implemented, particularly in districts that had cases in both livestock and humans. Vaccination, however, was implemented too late and the coverage achieved was too low to be effective. The authors suggest ways to improve the capacity of the DVS to respond to similar outbreaks in the future.

Item does not contain fulltext OBJECTIVES: Endolymphatic sac tumors (ELSTs) are rare adenomatous tumors arising in the petrous bone, either spontaneously (isolated) or in association with von Hippel-Lindau (VHL) disease. For 9 patients, this study describes the typical features and management of ELST and the clinical outcome of treatment. Similarities and differences are identified for ELST in isolation and in association with VHL disease. STUDY DESIGN: Case series. SETTING: Tertiary referral center. PATIENTS: The patient database was searched for patients diagnosed with ELST. All other tertiary referral centers in The Netherlands were invited to do likewise. INTERVENTIONS: The patient records were screened for presenting symptoms, hearing, imaging, treatment, and treatment outcome. Histopathologic finding was reviewed by a senior pathologist. RESULTS: Six patients with an isolated ELST and 3 patients with an ELST in association with VHL disease were identified. In the isolated ELST group, 5 patients were treated surgically and 1 patient was administered primary radiotherapy. In the VHL group, 1 patient underwent surgery and 2 patients were treated conservatively after a wait-and-magnetic resonance imaging-scan protocol. All individual treatment outcomes are scrupulously presented in this article. CONCLUSION: This study compiles and describes 9 cases of ELST. In 8 of 9 patients, the ELST could be controlled by surgery, radiotherapy, or a wait-and-scan protocol. The large interpatient differences make it difficult to standardize the management of this disease. The management is strongly influenced by comorbidity and tumor stage.

We conducted a field trial among Maasai cattle-keepers in Nkuruman and Nkineji areas of Kenya to evaluate the effectiveness of a synthetic tsetse-repellent technology developed for the control of trypanosomosis in cattle. The technology was a repellent (2-methoxy 4-methylphenol) emitted from dispensers attached to collars worn by cattle. Treatment was allocated at the herd level to ensure adequate protection of all the animals in a herd, with measurements of effectiveness conducted at the individual-animal level. The trial began in April 2005 and ran for 16 months including a baseline phase of 4 months. We recruited 12 herds in each area using a restricted random-sampling technique and distributed them equally into intervention (repellent) and control groups. Sample size was determined using a formal power calculation. Effectiveness or minimal worthwhile difference was defined as a 50% reduction in the incidence of trypanosome infection in the treated versus control group (effectiveness below which the technology was considered by experts as not viable compared to existing control techniques). All the animals in the recruited herds were screened monthly (buffy-coat technique) for trypanosome infections. The analysis followed the principle of intention-to-treat by which subjects are analysed according to their initial treatment assignment, regardless of the mechanical performance of the device. Crude and adjusted effects of the technology were 23% (p

A project implemented from 2003 to 2005 trained women in Chitwan District, Nepal, in hygienic dairy production using a process of social mobilization. The aim of this research was to assess if the prevalence of mastitis in water buffalo in the households of women who were trained was lower one year after training than in untrained households, if the training influenced knowledge and practices for the prevention or control of mastitis, and if these practices and knowledge were associated with a lower prevalence of mastitis. A total of 202 households from Eastern and Western Chitwan District were included in the study. Of these, 60 households had participated in the project and 142 had not. Milk samples were collected from 129 households (33 project households and 96 non-project households). Clinical mastitis was determined using visual inspection of udders and detection of macroscopic clots and flakes in milk. The California Mastitis Test was used to diagnose sub-clinical mastitis from milk samples, and the IDEXX SNAP test to identify the presence of tetracycline residues. The prevalence of mastitis in trained households (39.4%) was 43.78% of that in untrained households (60.4%), lower but not significantly so (p = 0.08, 95% CI 0.17–1.12). Thirteen indicators of knowledge or practice for the control or prevention of mastitis were more likely to occur in trained households, four significantly so (not consuming milk from sick buffalo (p = 0.001), using soap to wash hands before milking (p = 0.001), discarding milk after antibiotic usage (p = 0.01), and choosing appropriate flooring for their livestock (p = 0.03)). Trained households that discarded milk from sick buffalo were 2.96 times more likely to have at least one animal with mastitis in the household (p = 0.03, 95% CI 1.15–7.65). Trained households that knew to wash buffalos’ teats after milking were less likely (OR 0.25) to have mastitis in their herd (p = 0.02, 95% CI 0.08–0.80). Of the 138 buffalos tested, only one tested positive for tetracycline residues.

To capture lessons from the 2007 Rift Valley fever (RVF) outbreak, epidemiological studies were carried out in Kenya and Tanzania. Somali pastoralists proved to be adept at recognizing symptoms of RVF and risk factors such as heavy rainfall and mosquito swarms. Sandik, which means "bloody nose," was used by Somalis to denote disease consistent with RVF. Somalis reported that sandik was previously seen in 1997/98, the period of the last RVF epidemic. Pastoralists communicated valuable epidemiological information for surveillance and early warning systems that was observed before international warnings. The results indicate that an all or none approach to decision making contributed to the delay in response. In the future, a phased approach balancing actions against increasing risk of an outbreak would be more effective. Given the time required to mobilize large vaccine stocks, emergency vaccination did not contribute to the mitigation of explosive outbreaks of RVF.

Background In mid-2015, the United States’ Pandemic Prediction and Forecasting Science and Technical Working Group of the National Science and Technology Council, Food and Agriculture Organization Emergency Prevention Systems, and Kenya Meteorological Department issued an alert predicting a high possibility of El-Niño rainfall and Rift Valley Fever (RVF) epidemic in Eastern Africa. Methodology/Principal findings In response to the alert, the Kenya Directorate of Veterinary Services (KDVS) carried out an enhanced syndromic surveillance system between November 2015 and February 2016, targeting 22 RVF high-risk counties in the country as identified previously through risk mapping. The surveillance collected data on RVF-associated syndromes in cattle, sheep, goats, and camels from >1100 farmers through 66 surveillance officers. During the 14-week surveillance period, the KDVS received 10,958 reports from participating farmers and surveillance officers, of which 362 (3.3%) had at least one syndrome. The reported syndromes included 196 (54.1%) deaths in young livestock, 133 (36.7%) abortions, and 33 (9.1%) hemorrhagic diseases, with most occurring in November and December, the period of heaviest rainfall. Of the 69 herds that met the suspect RVF herd definition (abortion in flooded area), 24 (34.8%) were defined as probable (abortions, mortalities in the young ones, and/or hemorrhagic signs) but none were confirmed. Conclusion/Significance This surveillance activity served as an early warning system that could detect RVF disease in animals before spillover to humans. It was also an excellent pilot for designing and implementing syndromic surveillance in animals in the country, which is now being rolled out using a mobile phone-based data reporting technology as part of the global health security system., Author summary Occurrence of Rift Valley Fever (RVF) outbreak is associated with heavy El-Niño rainfall. In July 2015, an alert on the likelihood of El-Niño rainfall and RVF outbreak in Eastern Africa region was issued by the United States, Food and Agriculture Organization, and Kenya Meteorological Department. In response to the alert, the Kenya Directorate of Veterinary Services (KDVS) carried out an enhanced syndromic surveillance system between November 2015 and February 2016 in the 22 counties that had previously been identified as RVF high-risk counties. The surveillance system collected data on RVF-associated syndromes and risk factors in cattle, sheep, goats and camels from more than 1100 farmers. Of the 10,958 field reports submitted, 45 were consistent with suspect RVF disease and 24 of these identified as probable RVF, triggering an immediate response. Whereas investigations of the suspect cases and laboratory testing did not confirm RVF cases, the surveillance system served as an excellent early warning system that could detect disease in animal before spillover to humans.

Introduction: Leptospirosis is a bacterial zoonotic disease with wide geographical spread. Its presence in Kenya and some of the neighbouring countries has been documented before and it is thought to contribute significantly to the number of febrile cases in human populations and abortions in livestock. This study investigated Leptospira spp. presence in rodents collected in both a pastoral and irrigated region of Kenya. Materials and methods: Blood and kidney samples were screened for leptospiral DNA by PCR, and ELISA was used to detect antibodies in tissue fluid. Results and discussion: Almost 42% (28/67) of the rodents were found to be PCR positive and 25% (14/56) by the ELISA test. Focus group discussions revealed that the local population perceived an increase in the rodent population and febrile illnesses not responsive to malarial treatment, a possible attestation of importance of non-malarial acute febrile illnesses such as leptospirosis in the communities. Conclusion: While the study was small, it indicated that rodents could play an important role as reservoir hosts for the bacteria in these areas.

The aim of the present study was to evaluate the microbial quality of the informally (street) vended foods in Harare. Samples of the staple food sadza (thickened maize porridge), stews (beef, chicken, goat), fried vegetables, salads, tap water and wash water, hand and surface swabs, were tested for the presence of selected pathogenic microorganisms. The food samples were tested for the presence of Bacillus cereus and Salmonella sp., while the water samples were tested for Escherichia coli . Hand and surface swabs were also taken and tested for the presence of Staphylococcus aureus and E. coli . The fried vegetables had the highest incidence of samples that tested positive for B. cereus (31%; n = 222) followed by salads (21%; n = 70). The salad (14%) and vegetable (7%) samples had the highest incidence of contamination with Salmonella sp., while sadza and the stews had fewer contaminated samples. The salads and fried vegetables therefore posed the greatest risk of food poisoning among the foods sold by the vendors. About 32% of hand swabs ( n = 251) were positive for S. aureus with only 6.4% positive for E. coli . Some swabs from spoons, knives, cutting boards and plates were also positive for E. coli and S. aureus , but with lower incidences compared to hand swabs. These results suggest that some of the vendors’ hands were unacceptably contaminated, indicating poor hygienic practices. Only three wash water samples ( n = 240) tested positive for E. coli , while none from the municipal water points ( n = 45) were positive. A comparison of surface and hand swabs between vending sites showed that the highly crowded markets had difficulties in meeting good hygienic standards. The training of vendors in food hygiene and provision of appropriate infrastructure were identified as key issues to the improvement of the safety of informally vended foods in Harare.