Browsing by Author "Hudson, Peter"

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Assessing Risk Factors for Trypanosome Infections in Cattle in Wildlife Interface Areas in Northern Tanzania
(Journal of Infectious Diseases and Epidemiology, 2019-05-04) Ngongolo, Kelvin; Estes, Anna; Hudson, Peter; Gwakisa, Paul
Trypanosomosis is a vector-borne, tropical disease that causes mortality and morbidity in livestock and humans. In this study we investigated the risk factors for trypanosome infection in cattle in the Maasai Steppe of northern Tanzania. We assessed the influence of age, sex, herd size and history of treatment against trypanosomosis as risk factors of trypanosome infection. Cattle blood samples were collected from 150 cattle in three villages in the vicinity of Tarangire National Park, which acts as a reservoir of tsetse flies, the trypanosome vector. Parasite species were identified using a nested Polymerase Chain Reaction (n-PCR). Smaller herd sizes, young age (1-2 years), and male sex significantly increased the risk of trypanosome infections. Efforts to control trypanosome infection should be strategically based on location and season while considering age, treatment and herd size as risk factors.
Empirical and model-based evidence for a negligible role of cattle in peste des petits ruminants virus transmission and eradication
(Nature Publishing Group UK, 2024-08-03) Herzog, Catherine; Aklilu, Fasil; Sibhatu, Demeke; Shegu, Dereje; Belaineh, Redeat; Mohammed, Abde; Schulz, Claudia; Willett, Brian; Bailey, Dalan; Hudson, Peter; Buza, Joram; Forza, Mesfin
Peste des petits ruminants virus (PPRV) is a multi-host pathogen with sheep and goats as main hosts. To investigate the role of cattle in the epidemiology of PPR, we simulated conditions similar to East African zero-grazing husbandry practices in a series of trials with local Zebu cattle (Bos taurus indicus) co-housed with goats (Capra aegagrus hircus). Furthermore, we developed a mathematical model to assess the impact of PPRV-transmission from cattle to goats. Of the 32 cattle intranasally infected with the locally endemic lineage IV strain PPRV/Ethiopia/Habru/2014 none transmitted PPRV to 32 co-housed goats. However, these cattle or cattle co-housed with PPRV-infected goats seroconverted. The results confirm previous studies that cattle currently play a negligible role in PPRV-transmission and small ruminant vaccination is sufficient for eradication. However, the possible emergence of PPRV strains more virulent for cattle may impact eradication. Therefore, continued monitoring of PPRV circulation and evolution is recommended.
Identification of Bacillus anthracis, Brucella spp., and Coxiella burnetii DNA signatures from bushmeat
(Springer Nature Limited, 2021-07-21) Katani, Robab; Schilling, Megan; Lyimo, Beatus; Eblate, Ernest; Martin, Andimile; Tonui, Triza; Cattadori, Isabella; Francesconi, Stephen; Estes, Anna; Rentsch, Dennis; Srinivasan, Sreenidhi; Lyimo, Samson; Munuo, Lidia; Tiambo, Christian; Stomeo, Francesca; Gwakisa, Paul; Mosha, Fausta; Hudson, Peter; Buza, Joram; Kapur, Vivek
Meat from wildlife species (bushmeat) represents a major source of dietary protein in low- and middle-income countries where humans and wildlife live in close proximity. Despite the occurrence of zoonotic pathogens in wildlife, their prevalence in bushmeat remains unknown. To assess the risk of exposure to major pathogens in bushmeat, a total of 3784 samples, both fresh and processed, were collected from three major regions in Tanzania during both rainy and dry seasons, and were screened by real-time PCR for the presence of DNA signatures of Bacillus anthracis (B. anthracis), Brucella spp. (Brucella) and Coxiella burnetii (Coxiella). The analysis identified DNA signatures of B. anthracis (0.48%), Brucella (0.9%), and Coxiella (0.66%) in a total of 77 samples. Highest prevalence rates of B. anthracis, Brucella, and Coxiella were observed in wildebeest (56%), dik-dik (50%), and impala (24%), respectively. Fresh samples, those collected during the rainy season, and samples from Selous or Serengeti had a greater relative risk of being positive. Microbiome characterization identified Firmicutes and Proteobacteria as the most abundant phyla. The results highlight and define potential risks of exposure to endemic wildlife diseases from bushmeat and the need for future investigations to address the public health and emerging infectious disease risks associated with bushmeat harvesting, trade, and consumption.
Identifying Age Cohorts Responsible for Peste Des Petits Ruminants Virus Transmission among Sheep, Goats, and Cattle in Northern Tanzania.
(MDPI, 2020-02-07) Herzog, Catherine; de Glanville, William; Willett, Brian; Cattadori, Isabella; Kapur, Vivek; Hudson, Peter; Swai, Emmanuel; Cleaveland, Sarah; Bjørnstad, Ottar; Buza, Joram
Peste des petits ruminants virus (PPRV) causes a contagious disease of high morbidity and mortality in global sheep and goat populations. To better control this disease and inform eradication strategies, an improved understanding of how PPRV transmission risk varies by age is needed. Our study used a piece-wise catalytic model to estimate the age-specific force of infection (FOI, per capita infection rate of susceptible hosts) among sheep, goats, and cattle from a cross-sectional serosurvey dataset collected in 2016 in Tanzania. Apparent seroprevalence increased with age, reaching 53.6%, 46.8%, and 11.6% (true seroprevalence: 52.7%, 52.8%, 39.2%) for sheep, goats, and cattle, respectively. Seroprevalence was significantly higher among pastoral animals than agropastoral animals across all ages, with pastoral sheep and goat seroprevalence approaching 70% and 80%, respectively, suggesting pastoral endemicity. The best fitting piece-wise catalytic models merged age groups: two for sheep, three for goats, and four for cattle. The signal of these age heterogeneities were weak, except for a significant FOI peak among 2.5-3.5-year-old pastoral cattle. The subtle age-specific heterogeneities identified in this study suggest that targeting control efforts by age may not be as effective as targeting by other risk factors, such as production system type. Further research should investigate how specific husbandry practices affect PPRV transmission.
Influence of Land Cover and Host Species on Trypanosome Infection in Cattle and its Socio-Economic Impacts to Pastoralists of the Maasai Steppe, Tanzania
(Journal of Infectious Diseases and Epidemiology, 2020-01-27) Ngongolo, Kelvin; Shirima, Gabriel; Mpolya, Emmanuel; Estes, Anna; Hudson, Peter; Gwakisa, Paul
Introduction Trypanosome infections result into trypanosomosis in cattle and this is an infection detrimental to pastoralist income. The patterns of transmission are thought to be influenced by ecological factors including wildlife and land cover. We assessed the influence of the relative abundance of wildlife and land cover (cultivation and habitat type) on the presence of trypanosome infections in replicated cattle herds of the Maasai Steppe. Methodology We undertook a cohort field study in three villages of the Maasai Steppe: Sukuro, Kimotorok and Oltukai. The study took place in July 2017 and October 2017 and utilized 50 cattle from each village. Pastoralists were asked questions during each visit when blood sampled were taken to seek their viewpoint on the relative abundance of wildlife, habitat types and cultivation observed in the areas their cattle grazed. In addition, the percentage cover of cultivated land and habitat types in the grazing areas were determined during field visits and participatory mapping with pastoralists. A systematic review was used to understand the socio-economic importance of trypanosomosis. The species of trypanosomes in cattle were identified using nested Polymerase chain reaction (n-PCR). Results There was a significant and positive association between the presence of trypanosome infection and the abundance of wildlife within grazing areas, in particular the abundance of buffaloes (Odd Ratio > 1, P = 0.038, 95% CI 1.26 to 1.38) when cattle grazed in woodland habitats. Cultivation on grazing areas had a negative association with the presence of trypanosome infections (R < 1, P = 0.001, 95% CI 0.0614 to 0.0986) in cattle but this varied between villages. A systematic review showed that trypanosomosis had socio-economic impacts such as loss of income, reduced quality, and quantity of livestock products, management cost, and inadequate provisions of socio-services and potential zoonotic transmission to humans. Conclusion & recommendations The socio-economic impacts of trypanosomosis will continue to be a challenge to pastoralists when cattle are grazed close to wildlife areas which are infested with tsetse fly habitats. Control strategies for trypanosome infection in cattle on the Maasai Steppe should consider the interaction of cattle with ecological factors.
Microbial Diversity in Bushmeat Samples Recovered from the Serengeti Ecosystem in Tanzania
(Nature Publishing Group UK, 2019-12-02) Katani, Robab; Schilling, Megan; Lyimo, Beatus; Tonui, Triza; Cattadori, Isabella; Eblate, Ernest; Martin, Andimile; Estes, Anna; Buza, Teresia; Rentsch, Dennis; Davenpor, Karen; Hovde, Blake; Lyimo, Samson; Munuo, Lydia; Stomeo, Francesca; Tiambo, Christian; Radzio-Basu, Jessica; Mosha, Fausta; Hudson, Peter; Buza, Joram; Kapur, Vivek
Bushmeat, the meat and organs derived from wildlife species, is a common source of animal protein in the diets of those living in sub-Saharan Africa and is frequently associated with zoonotic spillover of dangerous pathogens. Given the frequent consumption of bushmeat in this region and the lack of knowledge about the microbial communities associated with this meat, the microbiome of 56 fresh and processed bushmeat samples ascertained from three districts in the Western Serengeti ecosystem in Tanzania was characterized using 16S rRNA metagenomic sequencing. The results show that the most abundant phyla present in bushmeat samples include Firmicutes (67.8%), Proteobacteria (18.4%), Cyanobacteria (8.9%), and Bacteroidetes (3.1%). Regardless of wildlife species, sample condition, season, or region, the microbiome is diverse across all samples, with no significant difference in alpha or beta diversity. The findings also suggest the presence of DNA signatures of potentially dangerous zoonotic pathogens, including those from the genus Bacillus, Brucella, Coxiella, and others, in bushmeat. Together, this investigation provides a better understanding of the microbiome associated with this major food source in samples collected from the Western Serengeti in Tanzania and highlights a need for future investigations on the potential health risks associated with the harvesting, trade, and consumption of bushmeat in Sub-Saharan Africa
Microbial Diversity in Bushmeat Samples Recovered from the Serengeti Ecosystem in Tanzania
(Scientific Reports, 2019-12-02) Katani, Robab; Schilling, Megan; Lyimo, Beatus; Tonui, Triza; Cattadori, Isabella; Eblate, Ernest; Martin, Andimile; Estes, Anna; Buza, Teresia; Rentsch, Dennis; Davenport, Karen; Hovde, Blake; Lyimo, Samson; Munuo, Lydia; Stomeo, Francesca; Tiambo, Christian; Radzio-Basu, Jessica; Mosha, Fausta; Hudson, Peter; Buza, Joram; Kapur, Vivek
Bushmeat, the meat and organs derived from wildlife species, is a common source of animal protein in the diets of those living in sub-Saharan Africa and is frequently associated with zoonotic spillover of dangerous pathogens. Given the frequent consumption of bushmeat in this region and the lack of knowledge about the microbial communities associated with this meat, the microbiome of 56 fresh and processed bushmeat samples ascertained from three districts in the Western Serengeti ecosystem in Tanzania was characterized using 16S rRNA metagenomic sequencing. The results show that the most abundant phyla present in bushmeat samples include Firmicutes (67.8%), Proteobacteria (18.4%), Cyanobacteria (8.9%), and Bacteroidetes (3.1%). Regardless of wildlife species, sample condition, season, or region, the microbiome is diverse across all samples, with no significant difference in alpha or beta diversity. The findings also suggest the presence of DNA signatures of potentially dangerous zoonotic pathogens, including those from the genus Bacillus, Brucella, Coxiella, and others, in bushmeat. Together, this investigation provides a better understanding of the microbiome associated with this major food source in samples collected from the Western Serengeti in Tanzania and highlights a need for future investigations on the potential health risks associated with the harvesting, trade, and consumption of bushmeat in Sub-Saharan Africa
Molecular species identification of bushmeat recovered from the Serengeti ecosystem in Tanzania.
(PLOS ONE, 2020-09-14) Schilling, Megan; Estes, Anna; Eblate, Ernest; Martin, Andimile; Rentsch, Dennis; Katani, Robab; Joseph, Asteria; Kindoro, Fatuma; Lyimo, Beatus; Radzio-Basu, Jessica; Cattadori, Isabella; Hudson, Peter; Kapur, Vivek; Gwakisa, Paul; Buza, Joram
Bushmeat harvesting and consumption represents a potential risk for the spillover of endemic zoonotic pathogens, yet remains a common practice in many parts of the world. Given that the harvesting and selling of bushmeat is illegal in Tanzania and other parts of Africa, the supply chain is informal and may include hunters, whole-sellers, retailers, and individual resellers who typically sell bushmeat in small pieces. These pieces are often further processed, obscuring species-identifying morphological characteristics, contributing to incomplete or mistaken knowledge of species of origin and potentially confounding assessments of pathogen spillover risk and bushmeat offtake. The current investigation sought to identify the species of origin and assess the concordance between seller-reported and laboratory-confirmed species of origin of bushmeat harvested from in and around the Serengeti National Park in Tanzania. After obtaining necessary permits, the species of origin of a total of 151 bushmeat samples purchased from known intermediaries from 2016 to 2018 were characterized by PCR and sequence analysis of the cytochrome B (CytB) gene. Based on these sequence analyses, 30%, 95% Confidence Interval (CI: 24.4-38.6) of bushmeat samples were misidentified by sellers. Misreporting amongst the top five source species (wildebeest, buffalo, impala, zebra, and giraffe) ranged from 20% (CI: 11.4-33.2) for samples reported as wildebeest to 47% (CI: 22.2-72.7) for samples reported as zebra although there was no systematic bias in reporting. Our findings suggest that while misreporting errors are unlikely to confound wildlife offtake estimates for bushmeat consumption within the Serengeti ecosystem, the role of misreporting bias on the risk of spillover events of endemic zoonotic infections from bushmeat requires further investigation.
Pastoral production is associated with increased peste des petits ruminants seroprevalence in northern Tanzania across sheep, goats and cattle
(Cambridge University Press, 2019-07-18) Herzog, Catherine; de Glanville, William; Willett, Brian; Kibona, Tito; Cattadori, Isabella; Kapur, Vivek; Hudson, Peter; Buza, Joram; Cleaveland, Sarah; Bjørnstad, Ottar
Peste des petits ruminants virus (PPRV) causes a contagious disease of high morbidity and mortality in small ruminant populations globally. Using cross-sectional serosurvey data col- lected in 2016, our study investigated PPRV seroprevalence and risk factors among sheep, goats and cattle in 20 agropastoral (AP) and pastoral (P) villages in northern Tanzania. Overall observed seroprevalence was 21.1% (95% exact confidence interval (CI) 20.1–22.0) with 5.8% seroprevalence among agropastoral (95% CI 5.0–6.7) and 30.7% among pastoral villages (95% CI 29.3–32.0). Seropositivity varied significantly by management (production) system. Our study applied the catalytic framework to estimate the force of infection. The asso- ciated reproductive numbers (R0 ) were estimated at 1.36 (95% CI 1.32–1.39), 1.40 (95% CI 1.37–1.44) and 1.13 (95% CI 1.11–1.14) for sheep, goats and cattle, respectively. For sheep and goats, these R 0 values are likely underestimates due to infection-associated mortality. Spatial heterogeneity in risk among pairs of species across 20 villages was significantly posi- tively correlated (R2 : 0.59–0.69), suggesting either cross-species transmission or common, external risk factors affecting all species. The non-negligible seroconversion in cattle may represent spillover or cattle-to-cattle transmission and must be investigated further to under- stand the role of cattle in PPRV transmission ahead of upcoming eradication efforts.
Peste des petits ruminants Virus Transmission Scaling and Husbandry Practices That Contribute to Increased Transmission Risk: An Investigation among Sheep, Goats, and Cattle in Northern Tanzania
(MDPI, 2020-08-24) Herzog, Catherine; de Glanville, William; Willett, Brian; Cattadori, Isabella; Kapur, Vivek; Hudson, Peter; Buza, Joram; Swai, Emmanuel; Cleaveland, Sarah; Bjørnstad, Ottar
Peste des petits ruminants virus (PPRV) causes an infectious disease of high morbidity and mortality among sheep and goats which impacts millions of livestock keepers globally. PPRV transmission risk varies by production system, but a deeper understanding of how transmission scales in these systems and which husbandry practices impact risk is needed. To investigate transmission scaling and husbandry practice-associated risk, this study combined 395 household questionnaires with over 7115 cross-sectional serosurvey samples collected in Tanzania among agropastoral and pastoral households managing sheep, goats, or cattle (most managed all three, n = 284, 71.9%). Although self-reported compound-level herd size was significantly larger in pastoral than agropastoral households, the data show no evidence that household herd force of infection (FOI, per capita infection rate of susceptible hosts) increased with herd size. Seroprevalence and FOI patterns observed at the sub-village level showed significant spatial variation in FOI. Univariate analyses showed that household herd FOI was significantly higher when households reported seasonal grazing camp attendance, cattle or goat introduction to the compound, death, sale, or giving away of animals in the past 12 months, when cattle were grazed separately from sheep and goats, and when the household also managed dogs or donkeys. Multivariable analyses revealed that species, production system type, and goat or sheep introduction or seasonal grazing camp attendance, cattle or goat death or sales, or goats given away in the past 12 months significantly increased odds of seroconversion, whereas managing pigs or cattle attending seasonal grazing camps had significantly lower odds of seroconversion. Further research should investigate specific husbandry practices across production systems in other countries and in systems that include additional atypical host species to broaden understanding of PPRV transmission.