School of Biosecurity, Biotechnolgy and Laboratory Sciences (SBLS) Collection
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ItemSeroprevalence of rift valley fever virus and risk factors among domestic ruminants at the human- livestock- wildlife interfaces of Lake Mburo-Nakivale and Pian-Upe conservation areas(Makerere University, 2025)Rift Valley Fever (RVF) is one of the major zoonotic diseases in Uganda, affecting livestock, wildlife, and humans, and transmitted by mosquitoes. Although wildlife potentially harbors RVF virus (RVFV) strains, livestock exposure to RVFV at human-livestock-wildlife interfaces remains underexplored. This cross-sectional study was conducted in Satellite Research Sites (SRS) within Lake Mburo-Nakivale Conservation Area (LMCA) and Pian-Upe Conservation Area (PUCA). Using a 2- stage sampling design, livestock herds were randomly selected from the selected villages within the SRS. Blood samples and qualitative data were collected. A total of 1,572 livestock were sampled from both LMCA and PUCA. Serum samples were analyzed using a validated indirect ELISA RVF virus Nucleoprotein (NP) protocol to determine the seropositivity of anti-RVFV IgG antibodies. Descriptive, crude, and adjusted logistic regression analysis was performed on both laboratory and field data. Overall RVFV seroprevalence was 34.7% (546/1572), (95% CI, 32.4-37.1%). RVFV Seropositivity per conservation area was 38.3% (297/775) in LMCA, and 31.2% (249/797) in PUCA. RVFV Seropositivity per species was 41.3% (66/160) in sheep; 33.3% (290/870) in cattle and 35.1% (190/542) in goats. Multivariate logistic regression indicated that being over 5 years old (AOR = 1.4; 95% CI, 1.1-1.8; p=0.005), grazing in park and farm areas (AOR = 4.9; 95% CI, 1.7-14.2; p=0.003), and animals watered with piped water (AOR = 3.7; 95% CI, 1.1-12.0; p=0.030) or from rivers/streams (AOR = 2.3; 95% CI, 1.3-4.2; p=0.009) were significantly associated with RVFV exposure. There was high RVFV seropositivity reported among the domestic ruminants sampled in this study. More RVFV seropositive animals were distributed in herds closest to the national parks, and natural resources (lakes and rivers) in the areas. Animals older than 5 years, and herds which utilized both park and farm as grazing pattern, as well as those which were watered using piped water, and rivers or streams were seropositive at multivariate logistic regression analysis. These findings could guide in the development of effective RVF control strategies in these high risk areas of Uganda.
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ItemGenetic characterization of influenza viruses in bat populations in selected caves in Kapchorwa District(Makerere University, 2025)Bats are well-established reservoirs for a wide range of zoonotic viruses, including those with pandemic potential. Despite their significance as reservoirs for zoonotic viruses, the potential role of Ugandan bats in influenza virus transmission remains poorly characterized. Their ecological diversity and frequent interactions with human environments underscore the need for targeted surveillance in selected caves in Kapchorwa district. This study investigated the diversity of bat species, the detection, and genetic characteristics of influenza viruses in bat populations inhabiting selected caves in Kapchorwa district in 2022. Bats were captured using mist traps by trained field personnel and subsequently released after sampling. Using sterile swabs, oral and rectal swabs were collected from each captured bat for laboratory analysis. Bat species, sex, reproductive status, age class, and morphometric evaluation were conducted. Specimens were obtained and transported to the laboratory for further investigations. Molecular analysis was performed on all samples, and sequencing was conducted on the presumptive positive ones to genetically characterize the influenza viruses. In the selected caves in Kapchorwa district, six bat species were captured inhabiting caves in 2022, with Rhinolophus spp. being the most frequently sampled, followed by Myonycteris angolensis and Hipposideros ruber. Less frequently captured species included Nycteris thebaica, Coleura afra, and Miniopterus fraterculus. Influenza A viruses were detected in 0.59% (n=3/512) samples analyzed. The positive samples were all obtained from rectal swabs collected in 2022. Influenza detections were in Hipposideros ruber (n=2) and Rhinolophus eloquens/ fumigatus species complex (n=1), confirming that these species are potential reservoirs of influenza viruses. Molecular characterization of the positive samples showed strong alignments with the PB1 gene of the H18N11 influenza virus, confirming the presence of this distinct bat-specific virus lineage in those selected caves in Kapchorwa district. The high sequence identity and low E-values across all samples provide robust evidence of the genetic relationship between these local strains and previously identified H18N11 viruses from other regions. Although the influenza virus was found in only three (3) bats, which lowers the immediate risk to humans, it is important to monitor influenza strains circulating in bats for any changes that might make it more dangerous. We recommend protecting bat habitats, keeping track of bat-borne viruses regularly, and studying how these viruses interact with bats to better understand and prevent future health risks and outbreaks.
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ItemGenetic diversity and evolution of the measles virus in Uganda (2011-2023) based on the haemagglutinin gene and matrix fusion non-coding region( 2025)Measles is a highly contagious viral disease that remains a leading cause of childhood illness and death globally. Recent treatment advances exist, but sporadic outbreaks still occur due to factors like low vaccination rates, vaccine hesitancy, incomplete doses, and occasional vaccine ineffectiveness. This study employed Sanger sequencing technology to establish the measles virus diversity and evolution, focusing on the Matrix/Fusion-noncoding region (MF-NCR) and the hemagglutinin (H) gene, which have been demonstrated to have superior variability in contrast to the routinely used Nucleocapsid (N-450) gene. 245 samples that matched the inclusion criteria were screened for measles virus by qRT-PCR. One hundred twenty-nine Measles virus sequences (66 H gene, 63 MF-NCR) were generated from these samples, which had been collected from 29 districts during the period 2011-2023. Fifty-nine samples from 24 districts yielded Measles virus sequences for both the H gene and MF-NCR. All the study samples belonged to the B3 genotype and subgroups were seen within all 5 major clusters based on the H gene and MF-NCR. The MF-NCR showed a higher nucleotide variability of 3.3448×10⁻⁴ substitutions/site/year compared to the H gene that had 1.5521×10⁻⁴ substitutions/site/year. Fifty-two non-synonymous mutations were seen in the H gene of the study sequences, with 11 [R195I, N200D, S240N, K295R, G316S, E395G, N396D, A400V, G546S, D574N, Q575K] linked to epitope binding sites, and possibly contributing to vaccine ineffectiveness, especially those seen in the vaccinated but diseased population. Overall, these findings show that the H gene and MF-NCR can complement the routinely obtained N gene data in epidemiological classification and highlight major mutations at antigenic sites that need to further scrutiny to confirm if vaccine antibodies failed to neutralize the Measles virus due to detected mutations.
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ItemEvaluation of the anthelmintic efficacy of Albendazole, Levamisole and Ivermectin against gastrointestinal nematodes in tethered goats in Kole District, Uganda(Makerere University, 2025)Gastrointestinal nematode (GIN) infections pose a significant threat to goat productivity and health, particularly in the Kole district, where veterinary practitioners report minimal efficacy of anthelmintic drugs in treating confirmed infections. This study aimed to evaluate the prevalence, intensity of GIN infections, and the effectiveness of albendazole, levamisole, and ivermectin in tethered goats across selected sub-counties in Kole district. An experimental study was conducted with 90 tethered goats divided into four treatment groups (25-32 animals per group), given medication as per the drug manufacturer’s recommendation. The first group was given albendazole orally at a dosage of 5 mg/kg bodyweight, second group was given levamisole orally at a dosage of 7.5 mg/kg bodyweight, third group was given ivermectin subcutaneously at 0.2 mg/kg bodyweight and fourth group were the untreated controls. Pre-treatment (day 0) and post-treatment (day 14) fecal egg counts were conducted to assess drug efficacy using a fecal egg count reduction test (FECRT). The overall GIN prevalence was found to be 83.6%, with 44.9% of goats exhibiting low infection intensity (100-500 eggs per gram). Fecal flotation tests revealed the following prevalence of nematode eggs: strongyles (86%), Strongyloides spp. (31%), Trichuris spp. (2.5%), and Capillaria spp. (1%). Coprocultures identified Haemonchus spp., Cooperia spp., Oesophagostomum spp., Nematodirus spp., and Strongyloides spp. in pre-treatment samples, while only Haemonchus spp. was detected post-treatment in all drug groups. Fecal egg count reduction scores for ivermectin, levamisole, and albendazole were 86%, 73%, and 66% respectively, demonstrating gastrointestinal intestinal nematode resistance to the study drugs. This study underscores the need for targeted treatment strategies to enhance the efficacy of anthelmintics in goat populations.
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ItemBat ecology and social epidemiology of filoviruses in Uganda(Makerere University, 2025)Introduction: Filoviruses pose significant threats to both human and animal populations in Africa, particularly in Uganda, which ranks among the most affected by Ebola and Marburg virus outbreaks. These viruses are closely linked to bats, especially those in the Pteropodidae family. The 2022 outbreak of Sudan virus (Orthoebolavirus sudanense) in Uganda, reported 164 cases and 55 confirmed deaths before containment which underscores the ongoing risk of pathogen outbreak and spillover in the region. This is coupled with the prevailing traditional knowledge and systems with varying norms and beliefs that increase the bat-human interaction. The social epidemiological and ecological role of bats living in locales such as caves remains complex and largely unknown. Therefore, this study aimed to assess the relationship aspects of bat ecology and social epidemiology of filoviruses in central and western, Uganda. Materials and Methods: The study utilized a mixed methods approach to comprehensively assess bat ecology and social epidemiology of filoviruses in Uganda. This study utilized various methods including systematic review, quantitative surveys, participatory epidemiology, qualitative methods; focus group discussion (FGDs), key informant interviews (KIIs), and in-depth interviews (IDIs), bat fecal sample collection, respective laboratory-based techniques and mathematical modeling. The investigation consisted of five sub-studies each representing a study objective: Study 1: This was a systematic review adhering to PRISMA-P guidelines, examining relevant studies regarding bat ecological and behavioural factors as well as human actions that increase susceptibility to bat-borne pathogens. Data from published articles in different databases and grey literature were qualitatively analyzed, with key findings processed for reflexive thematic analysis in Excel to create themes. The themes generated were combined with Z-scores in R software for statistical analysis to create a Principal Component Analysis (PCA), cluster dendrogram and Pearson correlation for the variables within each theme. Study 2: To achieve this, the study utilized a mixed-methods approach involving surveys (n = 384) and FGDs with participants residing near bat caves in Bundibugyo district (western Uganda). Quantitively, the study assessed the knowledge aspects, perception and risk factors associated with bat exposure among persons living near bat roosting sites and analysed using descriptive statistics. Proportional piling through ranking was done using 10 FGDs (6–8 participants for each group) to explore community perceptions of activities associated with bat exposure and risk of bat-borne disease transmission. Study 3: This study was carried out in western Uganda i.e. Mubende and Kassanda districts which were known to have had Ebola cases. Qualitative data was collected through FGDs; n=4, IDIs; n=12, KIIs; n=12, and participatory landscape mapping to explore perceived drivers of the Ebola virus disease outbreak in the study areas. Thematic analysis using a deductive approach guided by social ecological model and epidemiological model in NVivo 12 pro software. Study 4: This study aimed to investigate the presence of filoviruses and characteristics of Kasokero (Masaka district, central region) and python caves (Rubirizi district, western region). To achieve this, 115 environmental bat fecal swab samples were collected and analysed using nested Reverse Transcriptase Polymerase Chain Reaction (RT-PCR). Additionally, the ecological characteristics were assessed through observation checklists. Study 5: This study developed and analyzed a stochastic model considering the bat-human-environment interface to assess the impacts on disease outbreak extinction and persistence. Using a multitype branching process, the model assessed transmission dynamics involving bats, humans, and environmental contamination. Parameters were based on existing data, incorporating bat excretions and human exposure behaviors. Numerical simulations of both deterministic and stochastic models depicted a major outbreak and persistence of the virus. Results: Study 1: Five key themes i.e. pathogen spillover from bats to humans, anthropogenic influences, pathways to spillover, seasonal and climate variability, and drivers of bat abundance and viral dynamics were identified related to bat and human leading to pathogen spillover. Among these, influence of anthropogenic activities and seasonal changes had a more significant role on transmission dynamics. The PCA highlighted strong correlations between bat abundance, viral dynamics, and environmental factors. Study 2: In total, 214/384 respondents (55.7%) had a history of bat exposure. Increased exposure to bats was associated with being male (OR = 1.6; 95% CI: 1.0, 2.4), staying in urban areas (OR=1.9; 95% CI: 1.2, 3.1), hunting (OR = 10.9; 95% CI: 1.4 to 87.6), and positive perception to bat guano being safe as fertiliser (OR= 2.5; 95% CI: 1.0, 5.9) and hunting was ranked as the major risk factor. Based on the provided data, the adjusted odds ratio of 0.7 for the good measures (95%CI: 0.4, 1.1), suggests a potential protective effect on the risk of bat exposure. Study 3: Five themes were identified as perceived drivers of Ebola virus outbreaks: (1) Individual factors (knowledge of EVD and fear from deaths of suspected cases); (2) Interpersonal factors (ecological, anthropogenic, environmental, and cultural sources of spillover); (3) Community impact (economic loss and lack of government support for survivors); (4) Organizational challenges (delayed lab results, inadequate reporting systems, and poor surveillance); and (5) Policy recommendations (One Health approach and ongoing public sensitization). Study 4: The study compared Kasokero and Python Caves, both home to fruit bats (Rousettus aegyptiacus). Python cave, with its larger colony size and water sources, supports greater bat populations. Kasokero cave features cultural practices at its entrance. No active viral shedding was revealed at the time of sampling despite the presence of large bat colonies. Despite verified RNA quality, the findings indicate a maximum filovirus prevalence of less than 0.02 at a 95% confidence level. Study 5: Through a multitype branching process approximation, it was demonstrated that both bats and humans can significantly increase the likelihood of disease outbreaks persisting. Managing environmental contamination alone is inadequate for controlling viral transmission without addressing infected hosts. The findings emphasize the need for a One Health approach, involving collaboration across public health, veterinary, wildlife, and environmental sectors, applicable to Marburg virus control. Conclusion: This thesis investigated the complex interactions between bats, humans, and the environment in Uganda regarding filovirus transmission. Through five studies, it highlights that spillover risks driven by human activities, viral dynamics, ecological and environmental factors, cultural norms, and seasonal changes along with bat exposure from hunting, gender roles, and geographical location, are crucial to transmission dynamics. The findings highlight that spillover is not solely due to ecological and environmental factors but is intensified by human behavior and socio- cultural practices, such as hunting, farming, and bat consumption, which increase bat-human interactions and amplify transmission. Understanding the ecology of bats alongside the associated social epidemiological dynamics is important for designing filovirus preparedness plans as well as heightening prevention and control of related outbreaks.