Diseases Commons^™

The Woah Global Wildlife Health Collaborating Centre Network (Woah-Wildnet): A Coordinated And Transformative Approach To Global Wildlife Health Challenges, David T.S. Hayman, Steve Unwin, Kelly Bateman, Casey Barton Behravesh, Charlotte Berg, Jemma Bergfeld, Cristina Casalone, Claire Cayol, Erin Davis, Sunday Ekesi, Johan Esterhuizen, Merid Getahun, Federica Giorda, Keith Hamilton, Damien O. Joly, Christa Kühn, Jean Claude Manuguerra, Daniel Masiga, Anita Michel, Paolo Mulatti, Misheck Mulumba, Annah Njui, Richard Paley, Antonio Fernández, Sascha Knauf, David P. Tchouassi, Youming Wang, Nathalie Vachiery, Jandouwe Villinger

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Introduction Wildlife health is integral to functioning, complex ecosystems [1], directly and indirectly influencing the health of people, animals, plants, and the environment [2–4]. Healthy wildlife populations are essential for ecosystem services and are at the heart of the One Health approach [3,4], which aims to sustainably balance and optimize the health of people, animals, and ecosystems through multisectoral and transdisciplinary collaboration [5]. Despite its importance, wildlife health initiatives often operate in silos, limiting capacity to address transboundary threats such as emerging diseases, pollution, and environmental changes. Anthropogenic changes, including habitat loss, degradation, fragmentation, and unsustainable harvesting, exacerbate wildlife health …

A Systematic Review And Meta-Analysis Of Mosquito Arboviral Infections Detected Through Xenosurveillance In Africa: A Focus On West Nile, Rift Valley Fever, And Chikungunya Virus Infections, Mxolisi Mgongoma, Armanda Bastos, Abel Ramoelo, David P. Tchouassi

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This systematic review and meta-analysis comprehensively evaluated the mosquito arboviral infections with West Nile virus (WNV), Rift Valley fever virus (RVFV), and chikungunya virus (CHIV), detected through xenosurveillance, reported in mosquito vectors across Africa in the last 25 years (2000–2024). The study analysed xenosurveillance data from 45 studies conducted with over 115,000 mosquito specimens, and incorporated moderator analyses to assess the influence of trap type, seasonality, regional location, settlement type, and screening methods on virus detection rates. The estimated pooled prevalence of WNV was 1.18% (95% CI: 0.60–3.43%), with higher rates observed in Culex quinquefasciatus and Culex pipiens, particularly in …

Roles Of Cytokines In Modulating Trypanosoma Brucei Rhodesiense Infection Outcomes In Vervet Monkeys, Clarah Jebet, John Kibuthu Thuita, Daniel Masiga, Benedict Owino Orindi, John Oidho, Mark C. Field, Enock Matovu, Vincent Owino Adung’A

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Introduction:

Human African trypanosomiasis (HAT), caused by Trypanosoma brucei rhodesiense, is categorized as acute due to rapid disease progression but presents varying clinical outcomes. Although the mechanisms underpinning differential clinical progression are poorly understood, both host and parasite factors are implicated. Therefore, we sought to elucidate roles of primate host factors in mediating varying T. b. rhodesiense infection outcomes.

Methods:

Here, we assessed the roles of selected host cytokines in disease progression using a tsetse-mediated infection in a non-human primate (NHP) vervet monkey model that closely mimics HAT and natural infection. We quantified eight cytokines, including TNF-α, IFN-γ, IL-10, IL-6, …

Exploring The Microbiomes Of Camel Ticks To Infer Vector Competence: Insights From Tissue-Level Symbiont-Pathogen Relationships, Rua Khogali, Armanda Bastos, Dennis Getange, Joel L. Bargul, Shewit Kalayou, Nehemiah Ongeso, Joost Theo Petra Verhoeven, James Kabii, John Ngiela, Daniel Masiga, Jandouwe Villinger

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Ticks are blood-feeding ectoparasites that harbor diverse pathogens and endosymbionts. Their microbial communities vary based on tick species, stage, sex, geographical location, surrounding environment, and tissue type. Understanding tick microbiota at the tissue level is crucial for unraveling how microbiomes are distributed in tick tissues and influence pathogen transmission. We used V1-V2 16 S rRNA gene sequencing to analyze tissue-specific bacterial compositions (hemolymph, saliva, salivary glands, and midgut) of Amblyomma gemma, Rhipicephalus pulchellus, Hyalomma dromedarii, and Hyalomma rufipes ticks collected from camels in Marsabit County, northern Kenya. The V1-V2 region of the 16 S rRNA gene effectively differentiated 43 Rickettsia …

Climate-Driven Potential For Tularemia In East Africa: Skill Testing And Ecological Consistency Of A Transferred Risk Model, Komi Mensah Agboka, Allan Muohi Ngángá, Bonoukpoè Mawuko Sokame, Steve Soh Bernard Baleba, Tobias Landmann, Elfatih M. Abdel-Rahman, Chrysantus M. Tanga, Souleymane Diallo

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Tularemia, a neglected zoonosis, remains underreported in Africa despite growing concern over its climate-driven expansion. This study aims to quantify the specific contribution of climate to tularemia risk using a climate attribution framework. We trained a Least Squares Dummy Variable (LSDV) fixed-effects panel model on United States (U.S.) county-level tularemia incidence data from 2011–2020 (n = 500, R² = 0.90), incorporating only climatic predictors: cumulative temperature, cumulative precipitation, and their respective variabilities. The climate-only model explained 86% of variance in the training data, demonstrating strong climate influence on tularemia disease dynamics. We then applied the model to East Africa, using …

Stomoxys Flies (Diptera, Muscidae) Are Competent Vectors Of Trypanosoma Evansi, Trypanosoma Vivax, And Other Livestock Hemopathogens, Julia W. Muita, Joel L. Bargul, John Mark O. Makwatta, Ernest M. Ngatia, Simon K. Tawich, Daniel K. Masiga, Merid N. Getahun

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Stomoxys flies are widely distributed and economically significant vectors of various livestock pathogens of veterinary importance. However, the role of Stomoxys spp. in pathogen transmission is poorly understood. Therefore, we studied the feeding patterns of these blood feeders collected from specific locations in Kenya to identify various vertebrate hosts they fed on, the livestock hemopathogens they carried, and to elucidate their role in pathogens transmission. Our findings show that field-collected Stomoxys flies carried several pathogens, including Trypanosoma spp., Anaplasma spp., and Theileria spp., which were also detected in the blood of sampled livestock, namely camels and cattle. The findings on …

Machine Learning Predicts Non-Preferred And Preferred Vertebrate Hosts Of Tsetse Flies (Glossina Spp.) Based On Skin Volatile Emission Profiles, Olabimpe Y. Orubuloye, David P. Tchouassi, Abdullahi A. Yusuf, Christian W.W. Pirk, Daniel K. Masiga, Edward Kariuki, Baldwyn Torto

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Tsetse fly vectors of African trypanosomosis preferentially feed on certain vertebrates largely determined by olfactory cues they emit. Previously, we established that three skin-derived ketones including 6-methyl-5-hepten-2-one, acetophenone and geranyl acetone accounted for avoidance of zebra by tsetse flies. Here, we tested the hypothesis that these three ketones serve as biomarkers for tsetse flies to distinguish between non-preferred- and preferred-vertebrate hosts. We used coupled gas chromatography/mass spectrometry to analyze and compare the skin volatile emissions of two non-preferred- (waterbuck and zebra) and four preferred- (buffalo, donkey, horse, warthog) vertebrate hosts in two wildlife parks in Kenya. We detected a total …

Challenges And Lessons From A Vector Control Campaign Targeting Glossina Palpalis Palpalis In An Isolated Protected Forest Area In Abidjan, Côte D’Ivoire, Yao Jean Rodrigue Konan, Bi Tra Dieudonné Ta, Djakaridja Berté, Bamoro Coulibaly, Kinifo Donatien Coulibaly, Nick Steven Egnankon, Foungniguée Diarrassouba, Kouassi Albert Djabo, Stéphanie Watier-Grillot, Jean Paul Demoncheaux, Koffi Alain De Marie Kouadio, Louis N’Dri, Philippe Solano, Sophie Ravel, Guy Pacôme Adingra, Antoine Barreaux, Adeline Ségard, Dramane Kaba, Vincent Jamonneau, Thierry De Meeûs, Vincent Djohan

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Vector control (VC) is one of the strategies employed to manage African trypanosomoses. This study aimed at assessing the effectiveness of a VC campaign against Glossina palpalis palpalis using tiny targets (TTs) impregnated with insecticide in an isolated, protected forest in Abidjan, Côte d’Ivoire, while considering ecological, genetic, and operational factors. Between January 2020 and September 2022, 2,712 TTs were deployed at 684 sites, covering a total area of 1.7 km2. VC monitoring was conducted using Vavoua traps during 12 evaluation surveys, between June 2020 and March 2023. Five months after the initial TT deployment, tsetse fly density had decreased …

An Overview Of Tsetse Fly Repellents: Identification And Applications, Olabimpe Y. Orubuloye, Njelembo J. Mbewe, David P. Tchouassi, Abdullahi A. Yusuf, Christian W.W. Pirk, Baldwyn Torto

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Tsetse flies are vectors of the parasite trypanosoma that cause the neglected tropical diseases human and animal African trypanosomosis. Semiochemicals play important roles in the biology and ecology of tsetse flies. Previous reviews have focused on olfactory-based attractants of tsetse flies. Here, we present an overview of the identification of repellents and their development into control tools for tsetse flies. Both natural and synthetic repellents have been successfully tested in laboratory and field assays against specific tsetse fly species. Thus, these repellents presented as innovative mobile tools offer opportunities for their use in integrated disease management strategies.

Exploring The Dynamic Adult Hard Ticks-Camel-Pathogens Interaction, John Mark O. Makwatta, Paul N. Ndegwa, Florence A. Oyieke, Peter Ahuya, Daniel K. Masiga, Merid N. Getahun

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The ability of ticks to interact and adapt to differentecologies and hosts determines their vectorial competence for various pathogens; however, ticks-livestock-pathogens interaction studies are limited. With our ticks-hosts-pathogens interface studies, we found 14 species of hard ticks feeding on various livestock. Ticks showed a strong preference for one-humped camels (Camelus dromedarius). The camel nostril was the most preferred predilection site. The most prevalent tick species on camels was Hyalomma rufipes. We found two novel Amblyomma gemma variants which are distinct both morphologically and genetically from previously described Amblyomma gemma. The signature odors from camel breath and body were attractive to …

Dual Suppression Of Glossina Pallidipes Using Entomopathogenic Fungal-Based Biopesticides And Sterile Insect Technique, Fidelis L.O. Ombura, Adly M.M. Abd-Alla, Komivi S. Akutse, Steven Runo, Paul O. Mireji, Rosemary Bateta, Joseck E. Otiwi, Inusa J. Ajene, Fathiya M. Khamis

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Tsetse flies and trypanosomosis significantly impact bovine production and human health in sub-Saharan Africa, exacerbating underdevelopment, malnutrition, and poverty. Despite various control strategies, long-term success has been limited. This study evaluates the combined use of entomopathogenic fungi (EPF) and the sterile insect technique (SIT) to combat tsetse flies. Eleven EPF isolates were tested against teneral males of Glossina pallidipes, focusing on mortality rates, radial growth, and impacts on fly fitness. Temperature effects on conidial growth, sporulation, and spore yield of SIT-compatible/tolerant strains were also assessed. The fungal isolates significantly influenced mortality rates in both unirradiated and irradiated (SIT-treated) males (p <  0.0001). Metarhizium anisopliae strains ICIPE 20, ICIPE 32, ICIPE 41, ICIPE 62, ICIPE 78, and Beauveria bassiana ICIPE 603 showed higher SIT compatibility/tolerance with LT50 values of 11–30 days, compared to other more virulent isolates with LT50 values of 4–9 days. Temperature significantly affected the radial growth of SIT-compatible EPF strains (p <  0.0001), with M. anisopliae ICIPE 78 exhibiting the fastest conidia growth at 25°C. Spore yield varied significantly across temperatures (15–40°C), and the thermal range for conidia germination of SIT-compatible strains was 8.1–45.4°C, with an optimal range of 26.7–31.1°C. Moreover, infected unirradiated females and irradiated males (donors) successfully transmitted conidia to untreated flies (receivers) without significant differences in survival rates (p = 0.6438) and no observed sex dimorphism. Our findings highlight the potential of combining EPF and SIT as a novel dual approach that could effectively and synergistically suppress tsetse fly populations.

Tissue-Specific Localization Of Tick-Borne Pathogens In Ticks Collected From Camels In Kenya: Insights Into Vector Competence, Rua Khogali, Armanda Bastos, Joel L. Bargul, Dennis Getange, James Kabii, Daniel Masiga, Jandouwe Villinger

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Background: Tick-borne pathogen (TBP) surveillance studies often use whole-tick homogenates when inferring tick-pathogen associations. However, localized TBP infections within tick tissues (saliva, hemolymph, salivary glands, and midgut) can inform pathogen transmission mechanisms and are key to disentangling pathogen detection from vector competence. Methods: We screened 278 camel blood samples and 504 tick tissue samples derived from 126 camel ticks sampled in two Kenyan counties (Laikipia and Marsabit) for Anaplasma, Ehrlichia, Coxiella, Rickettsia, Theileria, and Babesia by PCR-HRM analysis. Results: Candidatus Anaplasma camelii infections were common in camels (91%), but absent in all samples from Rhipicephalus pulchellus, Amblyomma gemma, Hyalomma dromedarii, …

Transferability Of Tsetse Habitat Models Between Different Regions In Kenya And Rwanda, Stella Gachoki, Anton Vrieling, Thomas A. Groen, Andrew Skidmore, Daniel Masiga

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Accurate and reliable information on the distribution of tsetse habitats is crucial for the effective management of African Trypanosomiasis in sub-Saharan Africa. However, conducting large-scale surveillance of tsetse flies to develop distribution maps is impractical due to vast areas infested and limited resources available. To address this challenge, we evaluated the applicability of tsetse habitat models developed in the intensively sampled Shimba Hills National Reserve in Kenya for both the wet and the dry season, to two other regions in Kenya (Ruma National Park and Nguruman Conservancy) and one region in Rwanda (Akagera National Park). The models utilized satellite-based estimates …

Effect Of Use Of Tsetse Repellant Collar Technology On The Farm Performance And Household Welfare Of Small-Scale Livestock Farmers In Kenya, Beatrice W. Muriithi, Kassie Menale, Gracious M. Diiro, Michael N. Okal, Daniel K. Masiga

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Tsetse-transmitted Animal African Trypanosomosis (AAT) is a disease of economic importance to livestock development in Sub-Saharan Africa. The disease is widely managed using trypanocides that are expensive for smallholders and associated with health risks due to drug residues in animal products and drug resistance. Developed recently by the International Centre of Insect Physiology and Ecology (icipe) and partners, the novel Tsetse repellent collar technology (TRCT) provides an effective alternative control measure that targets the tsetse fly vector of AAT. This study assessed the impact of TRCT on household welfare and food security by using ex-post non-experimental data obtained from 632 …

Characterizing Movement Patterns Of Nomadic Pastoralists And Their Exposure To Rift Valley Fever In Kenya, G. Mosomtai, J. L. Kasiiti, R. M. Murithi, P. Sandström, T. Landmann, O. W. Lwande, O. A. Hassan, C. Ahlm, R. Sang, M. Evander, Z. Szantoi, G. Ottavianelli

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The role of animal movement in spreading infectious diseases is highly recognized by various legislations and institutions such as the World Organisation for Animal Health and the International Animal Health Code. The increased interactions at the nexus of human-animal-ecosystem interface have seen an unprecedented introduction and reintroduction of new zoonotic diseases with high socio-economic impacts such as the COVID-19 pandemic. Rift Valley fever (RVF) is a zoonotic disease that affects both humans and animals and is transmitted by Aedes mosquitoes or through contact with the body fluids of infected animals. This study seeks to characterize movement patterns of pastoralist and …

Transcriptomic Profiling Of Trypanosoma Congolense Mouthpart Parasites From Naturally Infected Flies, Sara Silva Pereira, Kawira Mathenge, Daniel Masiga, Andrew Jackson

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Background: Animal African trypanosomiasis, or nagana, is a veterinary disease caused by African trypanosomes transmitted by tsetse flies. In Africa, Trypanosoma congolense is one of the most pathogenic and prevalent causes of nagana in livestock, resulting in high animal morbidity and mortality and extensive production losses. In the tsetse fly, parasites colonise the midgut and eventually reach the mouthparts, from where they can be transmitted as the fly feeds on vertebrate hosts such as cattle. Despite the extreme importance of mouthpart-form parasites for disease transmission, very few global expression profile studies have been conducted in these parasite forms. Methods: Here, …

Entomological Assessment Of Tsetse-Borne Trypanosome Risk In The Shimba Hills Human-Wildlife-Livestock Interface, Kenya, Faith I. Ebhodaghe, Armanda D.S. Bastos, Michael N. Okal, Daniel K. Masiga

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Shimba Hills is a wildlife area in Kenya and a major focus of tsetse-borne trypanosomes in East Africa. In Shimba Hills, tsetse-borne trypanosomes constrain animal health and smallholder livelihoods. However, epidemiological data to guide hotspot-targeted control of infections are limited. This study assessed the dynamics of tsetse-borne trypanosome risk in Shimba Hills with the objective to describe infection hotspots for targeted control. Tsetse flies (n = 696) collected in field surveys between November 2018 and September 2019 in Shimba Hills were characterized for chronological age and phenotypic sizes and screened for trypanosome and cattle DNA. Entomological inoculation rates for trypanosome …

Metabolites From Trypanosome-Infected Cattle As Sensitive Biomarkers For Animal Trypanosomosis, Merid N. Getahun, John Ngiela, John Mark O. Makwatta, Peter Ahuya, Tawich K. Simon, Samuel K. Kamau, Baldwyn Torto, Daniel Masiga

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Trypanosomes are important global livestock and human pathogens of public health importance. Elucidating the chemical mechanisms of trypanosome-relevant host interactions can enhance the design and development of a novel, next-generation trypanosomosis diagnostics. However, it is unknown how trypanosome infection affects livestock volatile odors. Here, we show that Trypanosoma congolense and Trypanosoma vivax infections induced dihydro-β- ionone and junenol, while abundance of dihydro-α-ionone, phenolics, p-cresol, and 3-propylphenol significantly elevated in cow urine. These biomarkers of trypanosome infection are conserved in cow breath and the urine metabolites of naturally infected cows, regardless of population, diet, or environment differences. Furthermore, treating trypanosome-infected cows …

Genetic Connectivity Of Trypanosomes Between Tsetse-Infested And Tsetse-Free Areas Of Kenya, Naomi N. Kimenyi, Kelvin M. Kimenyi, Nelson O. Amugune, Merid N. Getahun

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The prevalence rates of trypanosomes, including those that require cyclical transmission by tsetse flies, are widely distributed in Africa. Trypanosoma brucei and Trypanosoma congolense are actively maintained in regions where there are no tsetse flies although at low frequencies. Whether this could be due to an independent evolutionary origin or multiple introduction of trypanosomes due to continuous movement of livestock between tsetse-free and -infested areas is not known. Thus, the aim of the study was to carry out microsatellite genotyping to explore intra-specific genetic diversity between T. (Trypanozoon), T. congolense and Trypanosoma vivax from the two regions: tsetse infested and …

Case Studies From The Experience Of Early Career Researchers In East Africa In Building Community Engagement In Research, Joel L. Bargul, Denna M. Mkwashapi, Imelda Namagembe, Immaculate Nakityo, Annettee Nakimuli, Josaphat Byamugisha, Daniel Semakula, Janet Seeley, Nelson K. Sewankambo

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Background: In this paper, we explain how three early career researchers actively engaged community members in their health research projects in Kenya, Tanzania and Uganda, and what was learnt from the experience. The research project in Kenya was on camel trypanosomiasis and the role of camel biting keds (or louse flies) in disease transmission. The project in Tanzania looked at the effect of human immunodeficiency virus and antiretroviral therapy on fertility and ascertained the trends in the use of family planning services amongst women of reproductive age. The focus of the project in Uganda was the implementation of maternal death …

Farmers’ Knowledge, Perceptions, And Practices On Animal Trypanosomosis And The Tsetse Fly Vector: A Cross-Sectional Study Around Kenya’S Arabuko-Sokoke Forest Reserve At The Livestock-Wildlife Interface, Erick K. Serem, Joel L. Bargul, Moses M. Ngari, Osman A. Abdullahi, David M. Mburu

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Background: Animal African trypanosomosis (AAT) is a veterinary disease caused by trypanosomes transmitted cyclically by tsetse flies. AAT causes huge agricultural losses in sub-Saharan Africa. Both tsetse flies and trypanosomosis (T&T) are endemic in the study area inhabited by smallholder livestock farmers at the livestock-wildlife interface around Arabuko-Sokoke Forest Reserve (ASFR) in Kilifi County on the Kenyan coast. We assessed farmers’ knowledge, perceptions and control practices towards T&T. Methods: A cross-sectional study was conducted during November and December 2017 to collect data from 404 randomly selected cattle-rearing households using a structured questionnaire. Descriptive statistics were used to determine farmers’ knowledge, …

Molecular Detection Of Novel Anaplasma Sp. And Zoonotic Hemopathogens In Livestock And Their Hematophagous Biting Keds (Genus Hippobosca) From Laisamis, Northern Kenya, Daniel M. Mwaki, Kevin O. Kidambasi, Johnson Kinyua, Kenneth Ogila, Collins Kigen, Dennis Getange, Jandouwe Villinger, Daniel K. Masiga, Mark Carrington, Joel L. Bargul

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Background: Livestock are key sources of livelihood among pastoral communities. Livestock productivity is chiefly constrained by pests and diseases. Due to inadequate disease surveillance in northern Kenya, little is known about pathogens circulating within livestock and the role of livestock-associated biting keds (genus Hippobosca) in disease transmission. We aimed to identify the prevalence of selected hemopathogens in livestock and their associated blood-feeding keds. Methods: We randomly collected 389 blood samples from goats (245), sheep (108), and donkeys (36), as well as 235 keds from both goats and sheep (116), donkeys (11), and dogs (108) in Laisamis, Marsabit County, northern Kenya. …

The Combat Project: Controlling And Progressively Minimizing The Burden Of Vector-Borne Animal Trypanosomosis In Africa, Alain Boulangé, Veerle Lejon, David Berthier, Sophie Thévenon, Geoffrey Gimonneau, Marc Desquesnes, Samuel Abah, Prudenciène Agboho, Kalinga Chilongo, Tsegaye Gebre, Assane Gueye Fall, Dramane Kaba, Stefan Magez, Daniel Masiga, Enock Matovu, Aldjibert Moukhtar, Luis Neves, Pamela A. Olet, Soumaïla Pagabeleguem, William Shereni, Brice Sorli, Moeti O. Taioe, María Teresa Tejedor Junco, Rehab Yagi, Philippe Solano, Giuliano Cecchi

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Vector-borne diseases affecting livestock have serious impacts in Africa. Trypanosomosis is caused by parasites transmitted by tsetse flies and other blood-sucking Diptera. The animal form of the disease is a scourge for African livestock keepers, is already present in Latin America and Asia, and has the potential to spread further. A human form of the disease also exists, known as human African trypanosomosis or sleeping sickness. Controlling and progressively minimizing the burden of animal trypanosomosis (COMBAT) is a four-year research and innovation project funded by the European Commission, whose ultimate goal is to reduce the burden of animal trypanosomosis (AT) …

Occurrence, Diversity And Distribution Of Trypanosoma Infections In Cattle Around The Akagera National Park, Rwanda, S. Richard Gashururu, Ndichu Maingi, Samuel M. Githigia, Methode N. Gasana, Peter O. Odhiambo, Dennis O. Getange, Richard Habimana, Giuliano Cecchi, Weining Zhao, James Gashumba, Joel L. Bargul, Daniel K. Masiga

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Background African Trypanosomiases threaten the life of both humans and animals. Trypanosomes are transmitted by tsetse and other biting flies. In Rwanda, the African Animal Trypanosomiasis (AAT) endemic area is mainly around the tsetse-infested Akagera National Park (NP). The study aimed to identify Trypanosoma species circulating in cattle, their genetic diversity and distribution around the Akagera NP. Methodology A cross-sectional study was carried out in four districts, where 1,037 cattle blood samples were collected. The presence of trypanosomes was determined by microscopy, immunolog-ical rapid test VerY Diag and PCR coupled with High-Resolution Melt (HRM) analysis. A parametric test (ANOVA) was …

Satellite-Based Modelling Of Potential Tsetse (Glossina Pallidipes) Breeding And Foraging Sites Using Teneral And Non-Teneral Fly Occurrence Data, Stella Gachoki, Thomas Groen, Anton Vrieling, Michael Okal, Andrew Skidmore, Daniel Masiga

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Background: African trypanosomiasis, which is mainly transmitted by tsetse flies (Glossina spp.), is a threat to public health and a significant hindrance to animal production. Tools that can reduce tsetse densities and interrupt disease transmission exist, but their large-scale deployment is limited by high implementation costs. This is in part limited by the absence of knowledge of breeding sites and dispersal data, and tools that can predict these in the absence of ground-truthing. Methods: In Kenya, tsetse collections were carried out in 261 randomized points within Shimba Hills National Reserve (SHNR) and villages up to 5 km from the reserve …

An Update On The Distribution Of Glossina (Tsetse Flies) At The Wildlife-Human-Livestock Interface Of Akagera National Park, Rwanda, Richard S. Gashururu, Samuel M. Githigia, Methode N. Gasana, Richard Habimana, Ndichu Maingi, Giuliano Cecchi, Massimo Paone, Weining Zhao, Daniel K. Masiga, James Gashumba

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Background: Glossina (tsetse flies) biologically transmit trypanosomes that infect both humans and animals. Knowledge of their distribution patterns is a key element to better understand the transmission dynamics of trypanosomosis. Tsetse distribution in Rwanda has not been well enough documented, and little is known on their current distribution. This study determined the current spatial distribution, abundance, diversity, and seasonal variations of tsetse flies in and around the Akagera National Park. Methods: A longitudinal stratified sampling following the seasons was used. Biconical traps were deployed in 55 sites for 6 consecutive days of each study month from May 2018 to June …

Ehrlichia Spp. Close To Ehrlichia Ruminantium, Ehrlichia Canis, And “Candidatus Ehrlichia Regneryi” Linked To Heartwater-Like Disease In Kenyan Camels (Camelus Dromedarius), Mario Younan, Daniel O. Ouso, Boku Bodha, Edward K. Keitany, Hezron O. Wesonga, Rinah Sitawa, Joshua Kimutai, Wilson Kuria, Wario Sori Sake, Nicholas Svitek, Tobias Landmann, Diba Dida Wako, Jandouwe Villinger

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We present findings from an outbreak of a heartwater-like disease in camels that killed at least 2000 adult animals in Kenya in 2016. Clinical signs included excitability, head pressing, aimless wandering, recumbency, and fast breathing followed by death after about 4 days. The observed morbidity in one herd was 40% with an average mortality of 7.5% in animals that received early antibiotic treatments. In untreated adults, the case fatality rate reached 100%. Gross pathology showed pulmonary edema, pleural exudate, hydrothorax, hydropericardium, ascites, enlarged “cooked” liver, nephrosis, and blood in the abomasum and intestine. Using established PCR-based protocols for tick-borne pathogens, …

Molecular Detection Of Leishmania Donovani, Leishmania Major, And Trypanosoma Species In Sergentomyia Squamipleuris Sand Flies From A Visceral Leishmaniasis Focus In Merti Sub-County, Eastern Kenya, Barrack O. Owino, Jackline Milkah Mwangi, Steve Kiplagat, Hannah Njiriku Mwangi, Johnstone M. Ingonga, Alphine Chebet, Philip M. Ngumbi, Jandouwe Villinger, Daniel K. Masiga, Damaris Matoke-Muhia

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Background: Visceral leishmaniasis (VL) and zoonotic cutaneous leishmaniasis (ZCL) are of public health concern in Merti sub-County, Kenya, but epidemiological data on transmission, vector abundance, distribution, and reservoir hosts remain limited. To better understand the disease and inform control measures to reduce transmission, we investigated the abundance and distribution of sand fly species responsible for Leishmania transmission in the sub-County and their blood-meal hosts. Methods: We conducted an entomological survey in five villages with reported cases of VL in Merti sub-County, Kenya, using CDC miniature light traps and castor oil sticky papers. Sand flies were dissected and identified to the …

Gene Co-Expression Network Analysis Of Trypanosoma Brucei In Tsetse Fly Vector, Kennedy W. Mwangi, Rosaline W. Macharia, Joel L. Bargul

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Background: Trypanosoma brucei species are motile protozoan parasites that are cyclically transmitted by tsetse fly (genus Glossina) causing human sleeping sickness and nagana in livestock in sub-Saharan Africa. African trypanosomes display digenetic life cycle stages in the tsetse fly vector and in their mammalian host. Experimental work on insect-stage trypanosomes is challenging because of the difficulty in setting up successful in vitro cultures. Therefore, there is limited knowledge on the trypanosome biology during its development in the tsetse fly. Consequently, this limits the development of new strategies for blocking parasite transmission in the tsetse fly. Methods: In this study, RNA-Seq …

Prevalence Of Trypanosome Species In Cattle Near Ruma National Park, Lambwe Valley, Kenya: An Update From The Historical Focus For African Trypanosomosis, Shewit Kalayou, Michael Nyang Anga Okal, Peter Otieno Odhiambo, Kawira Mathenge, Daniel Ochieng Gamba, Edward Kariuki, Francis Mcodimba, Daniel Masiga

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The effective control of diseases in areas shared with wildlife depends on the validity of the epidemiologic parameters that guide interventions. Epidemiologic data on animal trypanosomosis in Lambwe valley are decades old, and the recent suspected outbreaks of the disease in the valley necessitate the urgent bridging of this data gap. This cross-sectional study estimated the prevalence of bovine trypanosomosis, identified risk factors, and investigated the occurrence of species with zoonotic potential in Lambwe valley. The area is ~324 km2, of which 120 km2 is the Ruma National Park. Blood was sampled from the jugular and marginal ear veins of …