http://localhost/xmlui/handle/123456789/1279 Medical Laboratory; Agriculture & environmental Biotecthology; Biochemistry; Molecular Medicine, Applied Epidemiology; Medicinal PhytochemistryPublic Health; 2026-05-08T10:02:42Z http://localhost/xmlui/handle/123456789/6938 Assessing the Bio-Efficacy, Physical Integrity, and Care Practices of Yorkool® Pyrethroid-Based Long-Lasting Insecticidal Nets after one Year of use in Seme, Kisumu County Achulu, Mercy Owendy The physical integrity and insecticide efficacy of long-lasting insecticide-treated nets (LLINs) are influenced by handling practices during use. This was an evaluation of Yorkool® pyrethroid-based LLINs after 12 months of use to determine the washing and drying practices, physical conditions, and bio-efficacy. This was a cross sectional household survey in an area where rectangular Yorkool® pyrethroid LLINs were distributed during the national mass net distribution campaign in 2021. Questionnaires were used for data collection, and bioassay tests were conducted on 30 randomly selected nets. A total of 262 household heads were interviewed, with their mean age being 46.9 years (SD 17.4 years), and the level of education was mainly primary (70.2%). Most households (71.8%) had 1 to 2 sleeping spaces. The households had 468 LLINs, with 95.1% having been washed at least once. About three-quarters (74.4%) of the LLINs had been washed using local bar soap, with 99.6 % having not been scrubbed on a hard surface during washing, and 72.1% were dried under a shade. Those evaluated for physical integrity and had at least one hole made up 77.8% of the nets and 57.2% were too torn and required replacement. Bio efficacy test recorded a mean KD of 92% after 1 hour, and a mean mortality of 86% after 24 hours. The nets that passed the WHO efficacy cut-off for mortality (≥ 80%) after 24 hours were 83.3%, and 70% passed the KD (≥ 95%) cut-off after 1 hour. In conclusion, while more than half of the Yorkool® LLINs needed replacement due to poor physical integrity after one year of use in the households, the bio-efficacy of the LLINs was relatively high with the mortality on vectors meeting the WHO threshold. Key words: Integrity, Efficacy, Bioassay, Washing, Drying, Knockdown MSc in Parasitology and Entomology 2026-05-04T00:00:00Z http://localhost/xmlui/handle/123456789/6936 Phenotypic and Genotypic Antimicrobial Resistance Profiles of Archived Klebsiella Isolates from Children Under Five Years of Age in Kisii and Homabay County Hospitals Rwigi, Doreen Wanjira The genus Klebsiella belongs to the Enterobacteriaceae family and comprises Gram negative, opportunistic, non-motile pathogen with a mucoid appearance. The gastrointestinal tract serves as a reservoir for transfer of resistance genes and is often the potential source for infections. Multidrug resistance strains of Klebsiella cause severe nosocomial and community-acquired infections that are difficult to eradicate using available antibiotics. The increase in the incidence of extended spectrum β lactamases (ESBL) producing Klebsiella spp, has become a serious problem worldwide, because of their antibiotic resistance. The emergence and spread of β lactamase-producing Klebsiella spp has been associated with a substantial healthcare burden resulting from therapeutic failures. Multidrug resistant Klebsiella strains are resistant to extended-spectrum beta-lactam antibiotics, aminoglycosides, and fluoroquinolones. The aim of this study was to determine phenotypic and genotypic antimicrobial resistance profiles of Klebsiella species from children under five years of age in Kisii and Homabay County hospitals (Western Kenya). Although AMR bacterial infections pose a disproportionate public health challenge in sub-Saharan Africa, epidemiological data are scarce in Kenya. This was a cross-sectional study involving the use of 245 archived Klebsiella isolates. Systematic random sampling was used, and Excel formula randomization was used to generate random numbers to have a representative sample size from the two study sites. Antimicrobial resistance profiling was conducted to determine phenotypic resistance patterns and ESBLs, and producing Klebsiella Pneumoniae and Klebsiella oxytoca using antimicrobial susceptibility tests methods described by Kirby Bauer, ESBL resistance genes were analyzed using conventional PCR. Descriptive analyses were used to characterize phenotypic AMR and carriage of β-lactamase-producing genes. The modified Poisson regression models were used to assess correlates of phenotypic AMR. The prevalence of β-lactamase carriage among Klebsiella spp. isolates at hospital discharge was 62.8% (154/245). The study reported more than 58.2% Klebsiella spp. isolates were resistant to a third-generation cephalosporin; more specifically, 154 (62.6%) were resistant to ceftriaxone, 148 (60.0%) were resistant to cefotaxime and 127 (52.0%) were resistant to ceftazidime. Antibiotic use during hospitalization (adjusted prevalence ratio [aPR] =4.51; 95%CI: 1.79-11.4, p<0.001), longer duration of hospitalization (aPR=1.42; 95%CI: 1.14-1.77, p<0.002), and access to treated water (aPR=1.38; 95%CI: 1.12-1.71, p<0.003), were significant predictors of phenotypically determined β-lactamase. All the 154 phenotypically determined β lactamase-producing Klebsiella spp. isolates had at least one genetic marker of β lactam/third-generation cephalosporin resistance. The most prevalent genes were CTX-M (92.2%; 95%CI: 86.8–95.9) and SHV (92.2%; 95%CI: 86.8–95.9) followed by TEM (57.1%; 95%CI: 48.9–65.1) and OXA (31.2%; 95%CI: 24.0–39.1), respectively. Carriage of β-lactamase producing Klebsiella spp in stool is common among children discharged from hospital in western Kenya and is associated with longer duration of hospitalization, antibiotic use, and surprisingly access to treated water. These findings emphasize the need for continued surveillance of antimicrobial susceptibility patterns to inform the development and implementation of appropriate treatment guidelines. In addition, the study recommends measures beyond antimicrobial stewardship and infection control within hospitals, improved xvi sanitation, and access to safe drinking water to mitigate the spread of β-lactamase producing Klebsiella pathogens. MSc in Medical Microbiology 2026-03-04T00:00:00Z http://localhost/xmlui/handle/123456789/6933 A Multi-Component Text-Based Behaviour Change Communication Intervention to Enhance HIV/AIDS Risk Reduction among Long-Distance Truckers in Kenya Paul, Cyrus Mutie Chronic neglect from mainstream HIV risk reduction services and risky sexual networks often expose Long-distance truckers (LDTs) to a high risk of HIV. As such, LDTs are routinely eligible for behaviour change communication (BCC) interventions on HIV/AIDS risk reduction. However, LDTs’ access to such interventions is mostly constrained by their constantly disruptive schedules. Thus, the study aimed to develop, validate, implement, and evaluate a multi-component text-based BCC intervention on HIV/AIDS risk reduction for LDTs. This was a concurrent triangulation mixed-methods study with a quantitative arm entailing a non-equivalent quasi-experimental design and a qualitative arm. The study was organized into baseline, intervention, and post-intervention phases. Initially, the LDTs were systematically sampled and then recruited into either the control (Namanga site) or the intervention arm (Busia site). Each study arm comprised 189 LDTs. At baseline, a pre-test was done to assess the baseline HIV/AIDS risk levels. Eighteen in-depth interviews and nine key informant interviews were used to collect qualitative data. Qualitative data were analyzed using a hybrid deductive-inductive approach with the QDA Miner software. Descriptive statistics and ordinal logistic regression were generated in R for the quantitative data. In phase two, an intervention informed by baseline findings was designed and validated by a team of 24 experts through an e-Delphi exercise. A two-proportion Z-test and a Cochran-Armitage test were used to compare the proportions of HIV/AIDS risk levels in both study arms. A Cramer’s V test was also used to calculate the intervention's effect size. Overall, above 80% of the LDTs were at moderate (30-39%) to high-risk (≥40%) of HIV at baseline. The predictors of the HIV/AIDS risk levels were age (aPOR=0.96; p=0.01), college/university level of education (aPOR=0.09; p=0.02), days spent away from a spouse/regular partner (aPOR=1.06; p<0.0001), monthly salaries of 15,000-30000 KSH (aPOR=0.26; p=0.007) and >30,000 KSH (aPOR=0.25; p=0.004). The barriers to HIV/AIDS risk reduction were mainly health system-related factors. Existing BCC strategies on HIV/AIDS risk reduction were media-based, healthcare worker-driven, peer-educator-driven, outreach-based, and NGO-driven. A total of 57 multi-component BCC items were rated by 24 experts in two rounds of an e-Delphi exercise. Subsequently, the BCC items were shared with participants in the intervention arm through a cloud-based text messaging platform (TD_Educator) for six months. Post-intervention, statistically significant (ꭓ2=72.25, df =1, p<0.001) higher proportions (50.62%) of low HIV/AIDS risk levels were observed in the intervention arm (Busia), an indication of a shift from high to lower risk levels following the BCC intervention, unlike the control arm (ꭓ2=0.84, d.f=2, p=0.657). Overall, the BCC intervention had a moderate effect (Cramér’s V = 0.3, χ² = 28.214, d.f. = 2, p < 0.001) on HIV/AIDS risk reduction. In conclusion, the multi-component text-based BCC intervention is considered an effective tool for enhancing HIV/AIDS risk reduction among LDTs. Thus, regular updates will be needed in the future, as the evidence for the intervention is expected to grow and evolve further. Doctor of Philosophy in Nursing (Community Health) 2026-05-04T00:00:00Z http://localhost/xmlui/handle/123456789/6931 Yellow Fever and Dengue Virus Circulation among Human and Mosquito Populations in Nguruman and Kerio Valley, Kenya Kibathi, Mercy Hokah Dengue virus (DENV) and Yellow fever virus (YFV) are RNA viruses belonging to the genus Flavivirus and family Flaviviridae. Their emergence and re-emergence have become crucial public health problems, especially in Sub-Saharan Africa. Due to inadequate surveillance and diagnosis, prevalence and burden may be significantly underestimated. The main objective was to determine the circulation of DENV and YFV in mosquito and human populations in Kerio Valley and Nguruman, Kenya. 480 serum samples were collected from patients aged 5 to 85 years in a cross-sectional survey from July 2020 - May 2023 and tested for neutralizing antibodies against yellow fever virus and dengue viruses employing the Plaque Reduction Neutralization Test. In addition, 1822 pools of Aedes mosquitoes were collected and tested for DENV and YFV using cell culture and Reverse Transcriptase Polymerase Chain Reaction. A structural questionnaire was used to collect key demographic data. Using age, gender, and occupation as covariates, a multinomial logistic regression model was used to forecast risk for each of the most common viruses. Results indicated that, overall, neutralizing antibodies against at least one of the Flaviviruses analyzed were detected in 33.13%; 159/480 (95% CI, 50.1–59.0%) of the total samples, with larger proportions found in Kerio Valley (30.2%, 145/480) than in Nguruman (2.92%, 14/480) (P<0.0001). Generally, YFV had the highest seropositivity (32.5%) compared to DENV (0.63%). Dengue-neutralizing antibodies were detected only in Nguruman, where the seropositivity was low at 2%. This may be attributed to the dryland ecology in Nguruman, combined with climate change, which creates an ideal environment for Aedes mosquitoes, promoting DENV transmission. In Kerio Valley, women showed a significantly higher seroprevalence of neutralizing antibodies (60.82%) compared to men (p-value < 0.001), whereas in Nguruman, seropositivity rates were higher in men than in women at 47.47 per cent (P = 0.049). The study further shows that a diverse range of Aedes stegomyia mosquitoes exist in Nguruman and Kerio Valley with Aedes aegypti being the most predominant species (49.85%) followed by Aedes metallicus (16.5%), Aedes simpsoni (14.78%), Aedes Chausseri (2.37%) and Aedes africanus (1.7%). Out of the 1822 pools of mosquitoes tested, 2.8% (51/1822) showed cytopathic effects (CPE) on Vero cells (CCL-81 and E6). Nguruman had 3.35% of pools with CPE, while Kerio Valley had 1.94%. No significant difference was noted in viral activity between the two sites (p-value = 0.081, 95% CI). All 51 pools tested negative for flavivirus using the flavivirus universal primers (FU1 and CFD2). Further, upon sequencing, YFV and DENV viruses were not isolated from CPE-positive pools from both sites. The absence does not imply that these viruses are non-existent in these regions; rather, it may indicate low infection rates or viruses were not in circulation during the sampling period. The study concludes that yellow fever and dengue viruses are circulating among the human population in Nguruman and Kerio Valley, presenting a significant public health concern. Despite the presence of mosquito vectors, the viruses were not isolated from Aedes mosquitoes. The findings recommend strengthening surveillance of YFV and DENV in human and mosquito populations and using advanced methods like metagenomic testing for improved virus detection in mosquito from Nguruman and Kerio Valley. Master of Science in Medical Virology 2026-02-16T00:00:00Z