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Background: In the Cameroon, previous efforts to identify Buruli ulcer (BU) through the mobilization of community health workers (CHWs) yielded poor results. In this paper, we describe the successful creation of a BU community of practice (BUCOP) in Bankim, Cameroon composed of hospital staff, former patients, CHWs, and traditional healers. Methods and principle findings: All seven stages of a well-defined formative research process were conducted during three phases of research carried out by a team of social scientists working closely with Bankim hospital staff. Phase one ethnographic research generated interventions tested in a phase two proof of concept study followed by a three- year pilot project. In phase three the pilot project was evaluated. An outcome evaluation documented a significant rise in BU detection, especially category I cases, and a shift in case referral. Trained CHW and traditional healers initially referred most suspected cases of BU to Bankim hospital. Over time, household members exposed to an innovative and culturally sensitive outreach education program referred the greatest number of suspected cases. Laboratory confirmation of suspected BU cases referred by community stakeholders was above 30%. An impact and process evaluation found that sustained collaboration between health staff, CHWs, and traditional healers had been achieved. CHWs came to play a more active role in organizing BU outreach activities, which increased their social status. Traditional healers found they gained more from collaboration than they lost from referral. Conclusion/ Significance: Setting up lines of communication, and promoting collaboration and trust between community stakeholders and health staff is essential to the control of neglected tropical diseases. It is also essential to health system strengthening and emerging disease preparedness. The BUCOP model described in this paper holds great promise for bringing communities together to solve pressing health problems in a culturally sensitive manner. [ABSTRACT FROM AUTHOR]

Background: Culex species are widespread across Cameroon and responsible for high burden of nuisance in most urban settings. However, despite their high nuisance, they remain less studied compared to anophelines. The present study aimed to assess Culex species distribution, susceptibility to insecticide, bionomics and role in Lymphatic Filariasis (LF) transmission in the city of Yaoundé. Methods: Mosquito collections were conducted from March to December 2017 using Centre for Disease Control light traps (CDC-LT), human landing catches (HLC) and larval collections. Mosquitoes were identified using morphological identification keys. Mosquitoes from the Culex pipiens complex were further identified using Polymerase Chain Reaction (PCR) to assess the presence of sibling species. Bioassays were conducted with 2–5 day-old unfed females to assess mosquito susceptibility to DDT, permethrin, deltamethrin and bendiocarb following WHO guidelines. Dead, control and surviving mosquitoes from bioassays were screened by PCR to detect the presence of knockdown resistance (kdr) alleles. Pools of mosquitoes were examined by PCR to detect the presence of Wuchereria bancrofti. Results: A total of 197,956 mosquitoes belonging to thirteen species were collected. The density of mosquito collected varied according to the collection methods, districts and seasons. Culex quinquefasciatus emerged as the most abundant and the only species of the Culex pipiens complex in Yaoundé. Culex species were found breeding in different types of breeding sites including polluted and unpolluted sites. All Culex species including Cx antennatus, Cx duttoni, Cx perfuscus and Cx tigripes were found to be highly resistant to permethrin, deltamethrin and DDT. Culex quinquefasciatus was also found to be resistant to bendiocarb. A high frequency of the West Africa kdr allele was recorded in resistant Cx. quinquefasciatus. Out of the 247 pooled samples of 25 Culex spp. examined for the presence of Wuchereria bancrofti, none was found infected. Conclusion: The study confirms the high adaptation of Culex species particularly Culex quinquefasciatus to the urban environment and no implication of this species in the transmission of LF in Yaoundé Cameroon. Culex species predominance in urban settings highlight potential transmission risk of West Nile and rift valley fever in Yaoundé. [ABSTRACT FROM AUTHOR]

Background: Human African Trypanosomiasis (HAT) is a neglected tropical disease caused by infections due to Trypanosoma brucei subspecies. In addition to the well-established environmental and behavioural risks of becoming infected, there is evidence for a genetic component to the response to trypanosome infection. We undertook a candidate gene case-control study to investigate genetic associations further. Methodology: We genotyped one polymorphism in each of seven genes (IL1A, IL1RN, IL4RN, IL6, HP, HPR, and HLA-G) in 73 cases and 250 controls collected from 19 ethno-linguistic subgroups stratified into three major ethno-linguistic groups, 2 pooled ethno-linguistic groups and 11 ethno-linguistic subgroups from three Cameroonian HAT foci. The seven polymorphic loci tested consisted of three SNPs, three variable numbers of tandem repeat (VNTR) and one INDEL. Results: We found that the genotype (TT) and minor allele (T) of IL1A gene as well as the genotype 1A3A of IL1RN were associated with an increased risk of getting Trypanosoma brucei gambiense and develop HAT when all data were analysed together and also when stratified by the three major ethno-linguistic groups, 2 pooled ethno-linguistic subgroups and 11 ethno-linguistic subgroups. Conclusion: This study revealed that one SNP rs1800794 of IL1A and one VNTR rs2234663 of IL1RN were associated with the increased risk to be infected by Trypanosoma brucei gambiense and develop sleeping sickness in southern Cameroon. The minor allele T and the genotype TT of SNP rs1800794 in IL1A as well as the genotype 1A3A of IL1RN rs2234663 VNTR seem to increase the risk of getting Trypanosoma brucei gambiense infections and develop sleeping sickness in southern Cameroon. [ABSTRACT FROM AUTHOR]

Background: Mapping of lymphatic filariasis (LF) caused by Wuchereria bancrofti largely relies on the detection of circulating antigen using ICT cards. Several studies have recently shown that this test can be cross-reactive with sera of subjects heavily infected with Loa loa and thus mapping results in loiasis endemic areas may be inaccurate. Methodology/Principal findings: In order to develop an LF mapping strategy for areas with high loiasis prevalence, we collected day blood samples from 5,001 subjects residing in 50 villages that make up 6 health districts throughout Cameroon. Antigen testing using Filarial Test Strip (FTS, a novel platform that uses the same reagents as ICT) revealed an overall positivity rate of 1.1% and L. loa microfilaria (Mf) rates of up to 46%. Among the subjects with 0 to 8,000 Mf/ml in day blood, only 0.4% were FTS positive, while 29% of subjects with >8,000 Mf/ml were FTS positive. A Mf density of >8,200 Mf/ml was determined as the cut point at which positive FTS results should be excluded from the analysis. No FTS positive samples were also positive for W. bancrofti antibodies as measured by two different point of care tests that use the Wb123 antigen not found in L. loa. Night blood examination of the FTS positive subjects showed a high prevalence of L. loa Mf with densities up to 12,710 Mf/ml. No W. bancrofti Mf were identified, as confirmed by qPCR. Our results show that high loads of L. loa Mf in day blood are a reliable indicator of FTS positivity, and Wb123 rapid test proved to be relatively specific. Conclusions/Significance: Our study provides a simple day blood-based algorithm for LF mapping in loiasis areas. The results indicate that many districts that were formerly classified as endemic for LF in Cameroon are non-endemic and do not require mass drug administration for elimination of LF. [ABSTRACT FROM AUTHOR]

Background: Massangam health district (HD), in the West Region of Cameroon, has received ivermectin mass drug administration (MDA) for 20 years, however there is evidence of continued high transmission of Onchocerca volvulus. In order to better understand the transmission dynamics in the HD and inform intervention strategies there is a need to delineate the boundaries of the suspected area of high transmission within the wider transmission zone. Methodology/Principal findings: Parasitological and entomological surveys were conducted to map out the breeding sites of Simulium damnosum and evaluate the prevalence of onchocerciasis in neighbouring communities, including Makouopsap sentinel community. Potential rapids were prospected for identification of S. damnosum larvae and black flies collected to determine infectivity rates. Adults were assessed for the presence of O. volvulus microfilariae through a skin snip biopsy and examined for the presence of nodules. Anti Ov-16 antibodies were tested for in children. Four perennial breeding sites were identified on the Rivers Mbam and Nja. Large number of flies were collected along the River Mbam, especially in the rainy season, with up to 955 flies per day, suggesting this river is a perennial source of black flies. A total of 0.8% of parous flies were infective across the study area. Parasitological studies provided evidence of high rates of infection in the sentinel community and three neighbouring communities, with 37.1% of adults microfilariae positive in Makouopsap. High Ov-16 seropositivity in children also provided evidence of recent on-going transmission. In comparison, communities sampled further away from the sentinel community and neighbouring breeding sites were much closer to reaching onchocerciasis elimination targets. Conclusions/Significance: This study provides evidence of a particular geographic area of high transmission in an approximate 12 km range around the sentinel community of Makouopsap and the neighbouring breeding sites on the River Nja. To eliminate onchocerciasis by 2025, there is a need to explore alternative intervention strategies in this area of high transmission. [ABSTRACT FROM AUTHOR]

Background: Human African Trypanosomiasis (HAT) is a neglected disease targeted for elimination as a public health problem by 2020. Elimination requires a better understanding of the epidemiology and clinical evolution of HAT. In addition to the classical clinical evolution of HAT, asymptomatic carriers and spontaneous cure have been reported in West Africa. A genetic component to human susceptibility to HAT has been suggested to explain these newly observed responses to infection. In order to test for genetic associations with infection response, genetic polymorphism in 17 genes were tested (APOL1, IL1B, IL4, IL4R, IL6, IL8, IL12B, IL12RB1, IL10, TNFA, INFG, MIF, HLA-G, HLA-A, HP, HPR and CFH). Methodology: A case-control study was performed on 180 blood samples collected from 56 cases and 124 controls from Cameroon. DNA was extracted from blood samples. After quality control, 25 samples (24 controls and 1 case) were eliminated. The genotyping undertaken on 155 individuals including 55 cases and 100 controls were investigated at 96 loci (88 SNPs and 8 indels) located on 17 genes. Associations between these loci and HAT were estimated via a case-control association test. Results: Analyses of 64 SNPs and 4 indels out of 96 identified in the selected genes reveal that the minor allele (T) of rs8062041 in haptoglobin (HP) appeared to be protective against HAT (p = 0.0002395, OR 0.359 (CI95 [0.204–0.6319])); indicating higher frequency in cases compared to controls. This minor allele with adjusted p value of 0.0163 is associated with a lower risk (protective effect) of developing sleeping sickness. Conclusion: The haptoglobin related protein HPR and HP are tightly linked and both are duplicated in some people and may lead to higher activity. This increased production could be responsible of the protection associated with rs8062041 even though this SNP is within HP. [ABSTRACT FROM AUTHOR]

Introduction: Recurrent cholera outbreaks have been reported in Cameroon since 1971. However, case fatality ratios remain high, and we do not have an optimal understanding of the epidemiology of the disease, due in part to the diversity of Cameroon’s climate subzones and a lack of comprehensive data at the health district level. Methods/Findings: A unique health district level dataset of reported cholera case numbers and related deaths from 2000–2012, obtained from the Ministry of Public Health of Cameroon and World Health Organization (WHO) country office, served as the basis for the analysis. During this time period, 43,474 cholera cases were reported: 1748 were fatal (mean annual case fatality ratio of 7.9%), with an attack rate of 17.9 reported cases per 100,000 inhabitants per year. Outbreaks occurred in three waves during the 13-year time period, with the highest case fatality ratios at the beginning of each wave. Seasonal patterns of illness differed strikingly between climate subzones (Sudano-Sahelian, Tropical Humid, Guinea Equatorial, and Equatorial Monsoon). In the northern Sudano-Sahelian subzone, highest number of cases tended to occur during the rainy season (July-September). The southern Equatorial Monsoon subzone reported cases year-round, with the lowest numbers during peak rainfall (July-September). A spatial clustering analysis identified multiple clusters of high incidence health districts during 2010 and 2011, which were the 2 years with the highest annual attack rates. A spatiotemporal autoregressive Poisson regression model fit to the 2010–2011 data identified significant associations between the risk of transmission and several factors, including the presence of major waterbody or highway, as well as the average daily maximum temperature and the precipitation levels over the preceding two weeks. The direction and/or magnitude of these associations differed between climate subzones, which, in turn, differed from national estimates that ignored subzones differences in climate variables. Conclusions/Significance: The epidemiology of cholera in Cameroon differs substantially between climate subzones. Development of an optimal comprehensive country-wide control strategy for cholera requires an understanding of the impact of the natural and built environment on transmission patterns at the local level, particularly in the setting of ongoing climate change. [ABSTRACT FROM AUTHOR]

Background: The interaction between intestinal parasites and malaria is still not clear. Data in published literature are conflicting. We studied the effect of intestinal parasitic infection (IPI) on the clinical outcome of malaria in coinfected children. Methods: In a cross sectional study performed between October 2014 and September 2015, children infected with malaria, as demonstrated by the presence of asexual parasites in Giemsa stained blood films, were enrolled. Stool samples were obtained from participants and subjected to the formol-ether concentration technique for the detection of intestinal parasites. The Complete blood count was performed using an automated haematology analyser (Mindray, BC-2800). The risk ratio, Pearson’s chi-square and the student T test were all performed as part of the statistical analyses. Statistical significance was set at p < 0.05. Results: In all, 405 children successfully took part in the study. The children were between 1 week and 120 months of age (mean ± SD = 41.5 ± 33.5). Coinfection with intestinal parasites was observed in 11.6%. The rate of severe malaria (SM) attack in this study was 10.9%. SM was not observed to be associated with age (p = 0.377) or gender (p = 0.387), meanwhile coinfection with intestinal parasites was associated with age (p = 0.003). Among SM cases, IPI prevalence was higher in children with mild (WHO group 3) severe malaria (p = 0.027). Overall, IPI was not observed to be associated with SM (p = 0.656) or malaria parasite density (p = 0.185) or haemoglobin concentration (p = 0.205). The main clinical features of SM observed were hyperpyrexia (68.2%), severe malarial anaemia (61.4%), and multiple convulsion (52.3%). Conclusion: IPI was not observed to be associated with the severity of malaria, the malaria parasite density, and the haemoglobin concentration in coinfected children in Cameroon. The clinical outcome of malaria in children coinfected with intestinal parasites may depend on the geographical setting after all. [ABSTRACT FROM AUTHOR]

Background: Recent reports of transmission interruption of Onchocerca volvulus, the causing agent of river blindness, in former endemic foci in the Americas, and more recently in West and East Africa, raise the question whether elimination of this debilitating disease is underway after long-term treatment of the population at risk with ivermectin. The situation in Central Africa has not yet been clearly assessed. Methods and findings: Entomologic data from two former endemic river basins in North Cameroon were generated over a period of 43 and 48 months to follow-up transmission levels in areas under prolonged ivermectin control. Moreover, epidemiologic parameters of animal-borne Onchocerca spp. transmitted by the same local black fly vectors of the Simulium damnosum complex were recorded and their impact on O. volvulus transmission success evaluated. With mitochondrial DNA markers we unambiguously confirmed the presence of infective O. volvulus larvae in vectors from the Sudan savannah region (mean Annual Transmission Potential 2009–2012: 98, range 47–221), but not from the Adamawa highland region. Transmission rates of O. ochengi, a parasite of Zebu cattle, were high in both foci. Conclusions/significance: The high cattle livestock density in conjunction with the high transmission rates of the bovine filaria O. ochengi prevents the transmission of O. volvulus on the Adamawa plateau, whereas transmission in a former hyperendemic focus was markedly reduced, but not completely interrupted after 25 years of ivermectin control. This study may be helpful to gauge the impact of the presence of animal-filariae for O. volvulus transmission in terms of the growing human and livestock populations in sub-Saharan countries. [ABSTRACT FROM AUTHOR]

Background: Human co-infection with malaria and helmimths is ubiquitous throughout Africa. Nevertheless, its public health significance on malaria severity remains poorly understood. Methodology/Principal Findings: To contribute to a better understanding of epidemiology and control of this co-infection in Cameroon, a cross-sectional study was carried out to assess the prevalence of concomitant intestinal geohelminthiasis and malaria, and to evaluate its association with malaria and anaemia in Nkassomo and Vian. Finger prick blood specimens from a total of 263 participants aged 1–95 years were collected for malaria microscopy, assessment of haemoglobin levels, and molecular identification of Plasmodium species by PCR. Fresh stool specimens were also collected for the identification and quantification of geohelminths by the Kato-Katz method. The prevalence of malaria, geohelminths, and co-infections were 77.2%, 28.6%, and 22.1%, respectively. Plasmodium falciparum was the only malaria parasite species identified with mean parasite density of 111 (40; 18,800) parasites/µl of blood. The geohelminths found were Ascaris lumbricoides (21.6%) and Trichuris trichiura (10.8%), with mean parasite densities of 243 (24; 3,552) and 36 (24; 96) eggs/gram of faeces, respectively. Co-infections of A. lumbricoides and P. falciparum were the most frequent and correlated positively. While no significant difference was observed on the prevalences of single and co-infections between the two localities, there was a significant difference in the density of A. lumbricoides infection between the two localities. The overall prevalence of anaemia was 42%, with individuals co-infected with T. trichiura and P. falciparum (60%) being the most at risk. While the prevalence of malaria and anaemia were inversely related to age, children aged 5–14 years were more susceptible to geohelminthiasis and their co-infections with malaria. Conclusion/Significance: Co-existence of geohelminths and malaria parasites in Nkassomo and Vian enhances the occurrence of co-infections, and consequently, increases the risk for anaemia. [ABSTRACT FROM AUTHOR]

Background: To estimate the prevalence of trachoma in the North Region of Cameroon in order to facilitate the planning of trachoma control activities in this region, a survey was carried out in 2011 and 2012 in 15 health districts (HDs). Methodology: A cross-sectional, two-stage cluster random sampling survey was carried out. The survey focused on two target populations: children aged 1 to 9 years for the prevalence of Trachomatous Inflammation-Follicular (TF) and those aged 15 and over for the prevalence of Trachomatous Trichiasis (TT). The sample frame was an exhaustive list of villages and neighborhoods of HDs. The World Health Organization simplified trachoma grading system was used for the recognition and registration of cases of trachoma. Principal Findings: 30,562 children aged 1 to 9 years and 24,864 people aged 15 and above were examined. In children aged 1–9 years, the overall prevalence of TF was 4.2% (95% confidence intervals (CI): 4.0–4.5%). Three (3) of 15 HDs in the region showed TF prevalence of ≥10% (Poli, Rey Bouba, and Tcholliré). The overall TT prevalence was 0.25% (95% CI: 0.20–0.33%). There were estimated 1265 TT cases in the region. The prevalence of blindness was 0.01% (95% CI: 0.00–0.03%), low vision was 0.11% (95% CI: 0.07–0.17%), and corneal opacity was 0.22% (95% CI: 0.17–0.29%). Conclusions/Significance: This survey provides baseline data for the planning of activities to control trachoma in the region. The overall prevalence of TF in the region is 4.2%, and that of TT is 0.2%; three HDs have a TF prevalence ≥10%. These three HDs are eligible for mass drug administration with azythromycin, along with the implementation of the “F” and “E” components of the SAFE strategy. [ABSTRACT FROM AUTHOR]

The author explores the contributions of the African Programme for Onchocerciasis Control (APOC) for treating patients with onchocerciasis in 16 sub-Saharan countries including Cameroon, Congo and Ethiopia. Details on the updates health impact of the disease estimation based on disability weights from year 1995 to 2015 is discussed. The author also emphasizes the risk of skin disease in patients with onchocerciasis.

A previous survey for clinical cases of Buruli ulcer (BU) in the Mapé Basin of Cameroon suggested that, compared to older age groups, very young children may be less exposed to Mycobacterium ulcerans. Here we determined serum IgG titres against the 18 kDa small heat shock protein (shsp) of M. ulcerans in 875 individuals living in the BU endemic river basins of the Mapé in Cameroon and the Densu in Ghana. While none of the sera collected from children below the age of four contained significant amounts of 18 kDa shsp specific antibodies, the majority of sera had high IgG titres against the Plasmodium falciparum merozoite surface protein 1 (MSP-1). These data suggest that exposure to M. ulcerans increases at an age which coincides with the children moving further away from their homes and having more intense environmental contact, including exposure to water bodies at the periphery of their villages. [ABSTRACT FROM AUTHOR]

Background: Mycobacterium ulcerans (MU) is the agent responsible for Buruli Ulcer (BU), an emerging skin disease with dramatic socioeconomic and health outcomes, especially in rural settings. BU emergence and distribution is linked to aquatic ecosystems in tropical and subtropical countries, especially to swampy and flooded areas. Aquatic animal organisms are likely to play a role either as host reservoirs or vectors of the bacilli. However, information on MU ecological dynamics, both in space and time, is dramatically lacking. As a result, the ecology of the disease agent, and consequently its mode of transmission, remains largely unknown, which jeopardizes public health attempts for its control. The objective of this study was to gain insight on MU environmental distribution and colonization of aquatic organisms through time. Methodology/Principal Findings: Longitudinal sampling of 32 communities of aquatic macro-invertebrates and vertebrates was conducted from different environments in two BU endemic regions in Cameroon during 12 months. As a result, 238,496 individuals were classified and MU presence was assessed by qPCR in 3,084 sample-pools containing these aquatic organisms. Our study showed a broad distribution of MU in all ecosystems and taxonomic groups, with important regional differences in its occurrence. Colonization dynamics fluctuated along the year, with the highest peaks in August and October. The large variations observed in the colonization dynamics of different taxonomic groups and aquatic ecosystems suggest that the trends shown here are the result of complex ecological processes that need further investigation. Conclusion/Perspectives: This is the largest field study on MU ecology to date, providing the first detailed description of its spatio-temporal dynamics in different aquatic ecosystems within BU endemic regions. We argue that coupling this data with fine-scale epidemiological data through statistical and mathematical models will provide a major step forward in the understanding of MU ecology and mode of transmission. [ABSTRACT FROM AUTHOR]

Background: Kaposi's sarcoma associated herpesvirus (KSHV/HHV-8) is the causal agent of all forms of Kaposi sarcoma. Molecular epidemiology of the variable K1 region identified five major subtypes exhibiting a clear geographical clustering. The present study is designed to gain new insights into the KSHV epidemiology and genetic diversity in Cameroon. Methodology/Principal Findings: Bantu and Pygmy populations from remote rural villages were studied. Antibodies directed against latent nuclear antigens (LANA) were detected by indirect immunofluorescence using BC3 cells. Peripheral blood cell DNAs were subjected to a nested PCR amplifying a 737 bp K1 gene fragment. Consensus sequences were phylogenetically analyzed. We studied 2,063 persons (967 females, 1,096 males, mean age 39 years), either Bantus (1,276) or Pygmies (787). The Bantu group was older (42 versus 35 years: P<10−4). KSHV anti-LANA seroprevalence was of 37.2% (768/2063), with a significant increase with age (P<10−4) but no difference according to sex. Seroprevalence, as well as the anti-LANA antibodies titres, were higher in Bantus (43.2%) than in Pygmies (27.6%) (P<10−4), independently of age. We generated 29 K1 sequences, comprising 24 Bantus and five Pygmies. These sequences belonged to A5 (24 cases) or B (five cases) subtypes. They exhibited neither geographical nor ethnic aggregation. A5 strains showed a wide genetic diversity while the B strains were more homogenous and belonged to the B1 subgroup. Conclusion: These data demonstrate high KSHV seroprevalence in the two major populations living in Southern and Eastern Cameroon with presence of mostly genetically diverse A5 but also B K1 subtypes. [ABSTRACT FROM AUTHOR]

Background: For two decades, onchocerciasis control has been based on mass treatment with ivermectin (IVM), repeated annually or six-monthly. This drug kills Onchocerca volvulus microfilariae (mf) present in the skin and the eyes (microfilaricidal effect) and prevents for 3–4 months the release of new mf by adult female worms (embryostatic effect). In some Ghanaian communities, the long-term use of IVM was associated with a more rapid than expected skin repopulation by mf after treatment. Here, we assessed whether the embryostatic effect of IVM on O. volvulus has been altered following frequent treatment in Cameroonian patients. Methodology: Onchocercal nodules were surgically removed just before (D0) and 80 days (D80) after a standard dose of IVM in two cohorts with different treatment histories: a group who had received repeated doses of IVM over 13 years, and a control group with no history of large-scale treatments. Excised nodules were digested with collagenase to isolate adult worms. Embryograms were prepared with females for the evaluation of their reproductive capacities. Principal Findings: Oocyte production was not affected by IVM. The mean number of intermediate embryos (morulae and coiled mf) decreased similarly in the two groups between D0 and D80. In contrast, an accumulation of stretched mf, either viable or degenerating, was observed at D80. However, it was observed that the increase in number of degenerating mf between D0 and D80 was much lower in the frequently treated group than in the control one (Incidence Rate Ratio: 0.25; 95% CI: 0.10–0.63; p = 0.003), which may indicate a reduced sequestration of mf in the worms from the frequently treated group. Conclusion/Significance: IVM still had an embryostatic effect on O. volvulus, but the effect was reduced in the frequently treated cohort compared with the control population. [ABSTRACT FROM AUTHOR]