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Background: Kenya introduced a monovalent rotavirus vaccine administered orally at 6 and 10 weeks of age into her National Immunization Program in July 2014. The study evaluated the long-term impact of the vaccine on hospitalization for all-cause and rotavirus-specific acute gastroenteritis (AGE) and strain epidemiology in Kenya., Methods: Data on all-cause and rotavirus-specific AGE and strain distribution were derived from an eleven-year hospital-based surveillance of AGE among children aged <5 years at Kiambu County Teaching and Referral Hospital (KCTRH) in Central Kenya between 2009 and 2020. Fecal samples were screened for group A rotavirus using ELISA and genotyped using multiplex semi-nested RT-PCR. Trends in all-cause and rotavirus-related AGE and strain distribution were compared between the pre-vaccine (July 2009-June 2014), early post-vaccine (July 2014-June 2016) and late post-vaccine (February 2019-October 2020) periods., Results: Rotavirus-specific AGE was detected at 27.5% (429/1546, 95% CI: 25.5-30.1%) in the pre-vaccine period; 13.8% (91/658, 95% CI: 11.3-16.6%) in the early post-vaccine period (July 2014-June 2016); and 12.0% (229/1916, 95% CI: 10.6-13.5%) in the late post-vaccine period (February 2019-October 2020). This amounted to a decline of 49.8% (95% CI: 34.6%-63.7%) in rotavirus-specific AGE in the early post-vaccine period and 53.4% (95% CI: 41.5-70.3%) in the late post-vaccine period when compared to the pre-vaccine period. All-cause AGE hospitalizations declined by 40.2% (95% CI: 30.8%-50.2%) and 75.3% (95% CI: 65.9-83.1%) in the early post-vaccine and late post-vaccine periods, respectively, when compared to the pre-vaccine period. G3P [8] was the predominant strain in the late post-vaccine period, replacing G1P[8] which had predominated in the pre-vaccine and early post-vaccine periods. Additionally, we detected considerable proportions of uncommon strains G3P[6] (4.8%) and G12P[6] (3.5%) in the post-vaccine era., Conclusion: Rotavirus vaccination has resulted in a significant decline in all-cause and rotavirus-specific AGE, and thus, provides strong evidence for public health policy makers in Kenya to support the sustained use of the rotavirus vaccine in routine immunization. However, the shift in strain dominance and age distribution of rotavirus AGE in the post-vaccine era underscores the need for continued surveillance to assess any possible vaccine-induced selective pressure that could diminish the vaccine effectiveness over time., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Background: Water, sanitation and hygiene (WASH) and child health interventions are proven simple and cost-effective strategies for preventing diarrhea and minimizing excess mortality. Individually, they are able to prevent diarrhea though sub-optimally, and their effectiveness when combined may be higher. This study examined the effect of integrated WASH and maternal and child health (MCH) interventions on prevalence of diarrhea, in a resource-limited setting in Kenya., Methods: A controlled intervention was implemented in Narok County. The interventions included WASH interventions integrated with promotion of MCH. A structured questionnaire was used to collect data on targeted indicators before and after the interventions. Data were analyzed using descriptive statistics and Chi-square to establish the impact of the interventions., Results: A total of 431and 424 households and 491 and 487 households in intervention and control sites, respectively, participated in the baseline and endline surveys. Following implementation of the interventions, prevalence of diarrhea decreased by 69.1% (95% CI: 49.6-87.1%) and 58.6% (95% CI: 26.6-82.4%) in the intervention and control site, respectively. Treatment of drinking water and animal husbandry practices were significantly associated with diarrhea post-interventions., Conclusions: Integrating WASH interventions with other diarrhea control strategies and contextualizing them to meet site-specific needs may effectively prevent diarrhea., (© 2024. The Author(s).)

Globally, the emergence of the coronavirus disease (COVID-19) has had a significant impact on life. The need for ongoing SARS-CoV-2 screening employing inexpensive and quick diagnostic approaches is undeniable, given the ongoing pandemic and variations in vaccine administration in resource-constrained regions. This study presents results as proof of concept to use hybridization chain reaction (HCR) and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a complex for detecting SARS-CoV-2. HCR hairpin probes were designed using the NUPACK web-based program and further used to amplify the SARS-CoV-2 N gene in archived nasopharyngeal samples. The results were visualized using agarose gels and CRISPR Cas12a-based lateral flow strips. The assay was evaluated using the gold standard, real-time polymerase chain reaction (RT-PCR), as recommended by the World Health Organization (WHO). The results show the comparative efficiency of HCR to RT-PCR. This study shows that HCR and CRISPR are viable alternatives for diagnosing SARS-CoV-2 in samples.

Background: Influenza viruses are an important cause of respiratory infections across all age groups. Information on occurrence and magnitude of influenza virus infections in different populations in Kenya however remains scanty, compromising estimation of influenza disease burden. This study examined influenza infection in an urban high-income setting in Nairobi to establish its prevalence and activity of influenza viruses, and evaluated diagnostic performance of a rapid influenza diagnostic test., Methodology: A cross-sectional hospital-based study was conducted in six private health facilities located within high-income residential areas in Nairobi from January 2019 to July 2020. Patients of all ages presenting with influenza-like illness (ILI) were recruited into the study. Detection of influenza virus was conducted using rapid diagnosis and reverse transcription-polymerase chain reaction (RT-PCR). Data were summarized using descriptive statistics and tests of association. Sensitivity, specificity and area under receiver operating characteristics curve was calculated to establish diagnostic accuracy of the rapid diagnosis test., Results: The study recruited 125 participants with signs and symptoms of ILI, of whom 21 (16.8%) were positive for influenza viruses. Of all the influenza-positive cases, 17 (81.0%) were influenza type A of which 70.6% were pandemic H1N1 (A/H1N1 2009). Highest detection was observed among children aged 5-10 years. Influenza virus mostly circulated during the second half of the year, and fever, general fatigue and muscular and joint pain were significantly observed among participants with influenza virus. Sensitivity and specificity of the diagnostic test was 95% (95% confidence interval 75.1-99.9) and 100% (95% confidence interval 96.5-100.0), respectively., Conclusions: Findings of this study shows continuous but variable activity of influenza virus throughout the year in this population, with substantial disease burden. The findings highlight the need for continuous epidemiologic surveillance including genetic surveillance to monitor activity and generate data to inform vaccine introduction or development, and other interventions., (© 2022. The Author(s).)

Objectives: We assessed the impact of water, hygiene and sanitation (WASH), maternal, new-born and child health (MNCH), nutrition and early childhood development (ECD) on diarrhoea and microbial quality of water in a resource-constrained rural setting in Kenya., Methods: Through a controlled intervention study, we tested faecal and water samples collected from both the intervention and control sites before and after the interventions using microbiological, immunological and molecular assays to determine the prevalence of diarrhoeagenic agents and microbial quality of water. Data from the hospital registers were used to estimate all-cause diarrhoea prevalence., Results: After the interventions, we observed a 58.2% (95% CI: 39.4-75.3) decline in all-cause diarrhoea in the intervention site versus a 22.2% (95% CI: 5.9-49.4) reduction of the same in the control site. Besides rotavirus and pathogenic Escherichia coli, the rate of isolation of other diarrhoea-causing bacteria declined substantially in the intervention site. The microbial quality of community and household water improved considerably in both the intervention (81.9%; 95% CI: 74.5%-87.8%) and control (72.5%; 95% CI: 64.2%-80.5%) sites with the relative improvements in the intervention site being slightly larger., Conclusions: The integrated WASH, MNCH, nutrition and ECD interventions resulted in notable decline in all-cause diarrhoea and improvements in water quality in the rural resource-limited population in Kenya. This indicates a direct public health impact of the interventions and provides early evidence for public health policy makers to support the sustained implementation of these interventions., (© 2022 The Authors Tropical Medicine & International Health Published by John Wiley & Sons Ltd.)

Metal mesh devices (MMDs) are novel materials that enable the precise separation of particles by size. Structurally, MMDs consist of a periodic arrangement of square apertures of characteristic shapes and sizes on a thin nickel membrane. The present study describes the separation of aerosol particles using palm-top-size collection devices equipped with three types of MMDs differing in pore size. Aerosols were collected at a farm located in the suburbs of Nairobi, Kenya; aerosol particles were isolated, and pathogenic bacteria were identified in this microflora by next-generation sequencing analysis. The composition of the microflora in aerosol particles was found to depend on particle size. Gene fragments were obtained from the collected aerosols by PCR using primers specific for the genus Mycobacterium . This analysis showed that Mycobacterium obuense , a non-tuberculous species of mycobacteria that causes lung diseases, was present in these aerosols. These findings showed that application of this MMD analytical protocol to aerosol particles can facilitate the investigation of airborne pathogenic bacteria.

Human rotavirus strains having the unconventional G4P[6] genotype have been sporadically identified in diarrheic patients in different parts of the world. However, the whole genome of only one human G4P[6] strain from Africa (central Africa) has been sequenced and analyzed, and thus the exact origin and evolutionary pattern of African G4P[6] strains remain to be elucidated. In this study, we characterized the full genome of an African G4P[6] strain (RVA/Human-wt/KEN/KCH148/2019/G4P[6]) identified in a stool specimen from a diarrheic child in Kenya. Full genome analysis of strain KCH148 revealed a unique Wa-like genogroup constellation: G4-P[6]-I1-R1-C1-M1-A1-N1-T7-E1-H1. NSP3 genotype T7 is commonly found in porcine rotavirus strains. Furthermore, phylogenetic analysis showed that 10 of the 11 genes of strain KCH148 (VP7, VP4, VP6, VP1-VP3, NSP1, and NSP3-NSP5) appeared to be of porcine origin, the remaining NSP2 gene appearing to be of human origin. Therefore, strain KCH148 was found to have a porcine rotavirus backbone and thus is likely to be of porcine origin. Furthermore, strain KCH148 is assumed to have been derived through interspecies transmission and reassortment events involving porcine and human rotavirus strains. To our knowledge, this is the first report on full genome-based characterization of a human G4P[6] strain from east Africa. Our observations demonstrated the diversity of human G4P[6] strains in Africa, and provide important insights into the origin and evolutionary pattern of zoonotic G4P[6] strains on the African continent., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

We report the rapid detection (20 min) of Streptococcus agalactiae, Group B Streptococcus (GBS) employing on-chip magnetic isolation of GBS based on immiscible filtration assisted by surface tension (IFAST), followed by detection of the isolated GBS using an adenosine triphosphate (ATP) bioluminescence assay. Up to 80% GBS cells were isolated from spiked artificial urine samples with linear responses of bioluminescence signals from isolated cells at 2.3 × 102-9.1 × 105 CFU mL-1, demonstrating great promise for point-of-care detection of pathogenic bacteria in screening urine samples from pregnant women. Practical challenges during initial testing of the developed protocol with urine samples in Kenya are also described.

A monovalent rotavirus vaccine (RV1) was introduced to the national immunization program in Kenya in July 2014. There was increased detection of uncommon G3P[6] strains that coincided temporally with the timing of this vaccine introduction. Here, we sequenced and characterized the full genomes of two post-vaccine G3P[6] strains, RVA/Human-wt/KEN/KDH1951/2014/G3P[6] and RVA/Human-wt/KEN/KDH1968/2014/G3P[6], as representatives of these uncommon strains. On full-genomic analysis, both strains exhibited a DS-1-like genotype constellation: G3-P[6]-I2-R2-C2-M2-A2-N2-T2-E2-H2. Phylogenetic analysis revealed that all 11 genes of strains KDH1951 and KDH1968 were very closely related to those of human G3P[6] strains isolated in Uganda in 2012-2013, indicating the derivation of these G3P[6] strains from a common ancestor. Because the uncommon G3P[6] strains that emerged in Kenya are fully heterotypic as to the introduced vaccine strain regarding the genotype constellation, vaccine effectiveness against these G3P[6] strains needs to be closely monitored., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Objectives: A two-dose oral monovalent rotavirus vaccine (RV1) was introduced into the Kenyan National Immunization Program in July 2014. We assessed trends in hospitalisation for rotavirus-specific acute gastroenteritis (AGE) and strain distribution among children <5 years in a rural, resource-limited setting in Kenya before and after the nationwide implementation of the vaccine., Methods: Data on rotavirus AGE and strain distribution were derived from a 5-year hospital-based surveillance. We compared rotavirus-related hospitalisations and strain distribution in the 2-year post-vaccine period with the 3-year pre-vaccine baseline. Vaccine administrative data from the Unit of Vaccines and Immunization Services (UVIS) for Mbita sub-county were used to estimate rotavirus immunisation coverage in the study area., Results: We observed a 48% (95% CI: 27-64%) overall decline in rotavirus-related hospitalisations among children aged <5 years in the post-vaccine period. Coverage with the last dose of rotavirus vaccine increased from 51% in year 1% to 72% in year 2 of the vaccine implementation. Concurrently, reductions in rotavirus hospitalisations increased from 40% in the first year to 53% in the second year of vaccine use. The reductions were most pronounced among the vaccine-eligible group, with the proportion of cases in this age group dropping to 14% in post-vaccine years from a high of 51% in the pre-vaccine period. A diversity of rotavirus strains circulated before the introduction of the vaccine with G1P[8] being the most dominant strain. G2P[4] replaced G1P[8] as the dominant strain after the vaccine was introduced., Conclusions: Rotavirus vaccination has resulted in a notable decline in hospital admissions for rotavirus infections in a rural resource-limited population in Kenya. This provides early evidence for continued use of rotavirus vaccines in routine childhood immunisations in Kenya. Our data also underscore the need for expanding coverage on second dose so as to maximise the impact of the vaccine., (© 2018 John Wiley & Sons Ltd.)

A monovalent rotavirus vaccine (RV1) was introduced into the National Immunization Program in Kenya in July 2014. We examined the impact of the vaccine on hospitalization for all-cause acute gastroenteritis (AGE) and rotavirus-specific AGE and strain distribution at a large referral hospital which serves a predominantly peri-urban population in Central Kenya. Data on rotavirus AGE and strain distribution were derived from ongoing hospital-based AGE surveillance. Hospital administrative data were used to compare trends in all-cause AGE. Pre-vaccine (July 2009-June 2014) and post-vaccine (July 2014-June 2016) periods were compared for changes in hospitalization for all-cause AGE and rotavirus AGE and strain distribution. Following the vaccine introduction, the proportion of children aged <5years hospitalized for rotavirus declined by 30% (95% CI: 19-45%) in the first year and 64% (95% CI: 49-77%) in the second year. Reductions in rotavirus positivity were most pronounced among the vaccine-eligible group (<12months) in the first year post-vaccination at 42% (95% CI: 28-56%). Greater reductions of 67% (95% CI: 51-79%) were seen in the second year in the 12-23months age group. Similarly, hospitalizations for all-cause AGE among children <5years of age decreased by 31% (95% CI: 24-40%) in the first year and 58% (95% CI: 49-67%) in the second year of vaccine introduction. Seasonal peaks of rotavirus and all-cause AGE were reduced substantially. There was an increased detection of G2P[4], G3P[6] and G3P[8], which coincided temporally with the timing of the vaccine introduction. Thus, introducing the rotavirus vaccine into the routine immunization program in Kenya has resulted in a notable decline in rotavirus and all-cause AGE hospitalizations in Central Kenya. This provides early evidence for public health policy makers in Kenya to support the sustained use of the rotavirus vaccine in routine immunizations., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

In this study, a sensitive fluorescence sensor was developed for the detection of small, fluorescence-labeled particles dispersed in a solution. The prototype system comprises of a laser confocal optical system and a mechanical sample stage to detect photon bursting of fluorescence-labeled small particles in sample volumes less than 5 μL within 3 minutes. To examine the feasibility of the prototype system as a diagnostic tool, assemblages of rotavirus and fluorescence-labeled antibody were analyzed. The detection sensitivity for rotavirus was 1 × 10 4 pfu/mL. Rotavirus in stool samples from patients with acute gastroenteritis was also detected. The advantages and disadvantages of this immunosensor with respect to ELISA and RT-PCR, the current gold standards for virus detection, are discussed.

Between July 2009 and June 2014, a total of 1,546 fecal specimens were collected from children <5 years of age with acute gastroenteritis admitted to Kiambu County Hospital, Central Kenya. The specimens were screened for group A rotavirus (RVA) using ELISA, and RVA-positive specimens were subjected to semi-nested RT-PCR to determine the G and P genotypes. RVA was detected in 429/1,546 (27.5%) fecal specimens. RVA infections occurred in all age groups <59 months, with an early peak at 6-17 months. The infections persisted year-round with distinct seasonal peaks depending on the year. G1P[8] (28%) was the most predominant genotype, followed by G9P[8] (12%), G8P[4] (7%), G1P[4] (5%), G9P[4] (4%), and G12P[6] (3%). In the yearly change of G and P genotypes, a major shift from G9P[8] to G1P[8] was found in 2012. Phylogenetic analysis of the nucleotide sequences of the VP7 and VP4 genes of seven strains with unusual G8 or P[6] showed that the VP7 nucleotide sequences of G8 were clustered in lineage 6 in which African strains are included, and that there are at least two distinct VP4 nucleotide sequences of P[6] strains. These results represent basic data on RVA strains circulating in this region before vaccine introduction. J. Med. Virol. 89:809-817, 2017. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

Rotavirus gastroenteritis is an important cause of childhood morbidity and mortality in Kenya. In July 2014, Kenya introduced the rotavirus vaccine into her national immunization program. Although immunization coverage is crucial in assessing the real-world impact of this vaccine, variability in the vaccine coverage across the country is likely to occur. In view of this, we estimated the extent of coverage for the rotavirus vaccine at two socio-economically different sub-counties using the administrative data. The findings indicate disparities in vaccine coverage and access between the sub-counties and, thus, underscore the need to strengthen immunization systems to facilitate timely, accessible, and equitable vaccine delivery across the country. Both sub-counties recorded high vaccine dropout, suggestive of poor utilization of the vaccine. In this regard, increased social mobilization is needed to encourage vaccine compliance and to enhance tracking of vaccine defaulters. While efforts to improve the accuracy of the administrative coverage estimates are crucial, vaccination coverage surveys will be needed to verify the administrative coverage data and help identify specific factors relating to rotavirus vaccine coverage in the country.