Morbidity, mortality, and risk factors associated with Theileria parva seropositivity in a longitudinal calf study, Narok, Kenya
East Coast fever (ECF), caused by Theileria parva causes devastating loss to livestock keepers in sub-Saharan Africa. A longitudinal study was carried out in Narok County to estimate the incidence and risk factors associated with Theileria parva infection among calves. Calves were recruited within 5...
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Elsevier
2025-09-01
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| Series: | Veterinary and Animal Science |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2451943X25000328 |
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| author | Wyckliff Ngetich George Karuoya Gitau Tequiero Abuom Okumu Gabriel Oluga Aboge Daniel Muasya |
| author_facet | Wyckliff Ngetich George Karuoya Gitau Tequiero Abuom Okumu Gabriel Oluga Aboge Daniel Muasya |
| author_sort | Wyckliff Ngetich |
| collection | DOAJ |
| description | East Coast fever (ECF), caused by Theileria parva causes devastating loss to livestock keepers in sub-Saharan Africa. A longitudinal study was carried out in Narok County to estimate the incidence and risk factors associated with Theileria parva infection among calves. Calves were recruited within 5 weeks of birth and visited every six weeks to collect farm and calf level factors. A total of 1849 serum samples were collected and tested using an indirect enzyme-linked immunosorbent assay (ELISA). A multilevel multivariable logistic regression was used to determine associations between the seropositivity and different predictor variables. A total of 318 calves were recruited where 62 seroconverted during the follow up period. The overall risk of exposure was 26 %, with ECF-specific morbidity risk of 14.5 %. The cumulative incidence rate was 37 cases per 100 calf-years with higher incidence rate in agro-pastoral system. The crude mortality risk was 5.1 %, but four calves manifested classical signs of ECF resulting to clinical case-fatality risk of 44.4 %. In the final multivariable model, four variables were found to be significantly associated with T. parva seropositivity; calf age (OR 6.9; P < 0.01), calf sex (OR 1.4; P = 0.02), acaricide application (OR 0.5; P < 0.01) and spraying specific body parts (OR 2.5; P = 0.002). The results present the T. parva exposure patterns based on serological response in calves from birth to one year. These results will support evidence-based and effective practices for the management and control of ECF to mitigate the impact on productivity in the livestock sector. |
| format | Article |
| id | doaj-art-cbb20cc09e0e4fb792876e323d558657 |
| institution | Kabale University |
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| language | English |
| publishDate | 2025-09-01 |
| publisher | Elsevier |
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| series | Veterinary and Animal Science |
| spelling | doaj-art-cbb20cc09e0e4fb792876e323d5586572025-08-20T03:55:17ZengElsevierVeterinary and Animal Science2451-943X2025-09-012910045610.1016/j.vas.2025.100456Morbidity, mortality, and risk factors associated with Theileria parva seropositivity in a longitudinal calf study, Narok, KenyaWyckliff Ngetich0George Karuoya Gitau1Tequiero Abuom Okumu2Gabriel Oluga Aboge3Daniel Muasya4Department of Clinical Studies, University of Nairobi, P.O Box 29053-00625, Kangemi, Kenya; Department of Veterinary Surgery, Theriogenology and Medicine, Egerton University, P.O Box 536-20115, Egerton, Kenya; Corresponding author.Department of Clinical Studies, University of Nairobi, P.O Box 29053-00625, Kangemi, KenyaDepartment of Clinical Studies, University of Nairobi, P.O Box 29053-00625, Kangemi, KenyaDepartment of Public Health, Pharmacology and Toxicology, University of Nairobi, P.O Box 29053-00625, Kangemi, KenyaDepartment of Clinical Studies, University of Nairobi, P.O Box 29053-00625, Kangemi, KenyaEast Coast fever (ECF), caused by Theileria parva causes devastating loss to livestock keepers in sub-Saharan Africa. A longitudinal study was carried out in Narok County to estimate the incidence and risk factors associated with Theileria parva infection among calves. Calves were recruited within 5 weeks of birth and visited every six weeks to collect farm and calf level factors. A total of 1849 serum samples were collected and tested using an indirect enzyme-linked immunosorbent assay (ELISA). A multilevel multivariable logistic regression was used to determine associations between the seropositivity and different predictor variables. A total of 318 calves were recruited where 62 seroconverted during the follow up period. The overall risk of exposure was 26 %, with ECF-specific morbidity risk of 14.5 %. The cumulative incidence rate was 37 cases per 100 calf-years with higher incidence rate in agro-pastoral system. The crude mortality risk was 5.1 %, but four calves manifested classical signs of ECF resulting to clinical case-fatality risk of 44.4 %. In the final multivariable model, four variables were found to be significantly associated with T. parva seropositivity; calf age (OR 6.9; P < 0.01), calf sex (OR 1.4; P = 0.02), acaricide application (OR 0.5; P < 0.01) and spraying specific body parts (OR 2.5; P = 0.002). The results present the T. parva exposure patterns based on serological response in calves from birth to one year. These results will support evidence-based and effective practices for the management and control of ECF to mitigate the impact on productivity in the livestock sector.http://www.sciencedirect.com/science/article/pii/S2451943X25000328Theileria parvaSeropositivityIncidenceRisk factorsCalves |
| spellingShingle | Wyckliff Ngetich George Karuoya Gitau Tequiero Abuom Okumu Gabriel Oluga Aboge Daniel Muasya Morbidity, mortality, and risk factors associated with Theileria parva seropositivity in a longitudinal calf study, Narok, Kenya Veterinary and Animal Science Theileria parva Seropositivity Incidence Risk factors Calves |
| title | Morbidity, mortality, and risk factors associated with Theileria parva seropositivity in a longitudinal calf study, Narok, Kenya |
| title_full | Morbidity, mortality, and risk factors associated with Theileria parva seropositivity in a longitudinal calf study, Narok, Kenya |
| title_fullStr | Morbidity, mortality, and risk factors associated with Theileria parva seropositivity in a longitudinal calf study, Narok, Kenya |
| title_full_unstemmed | Morbidity, mortality, and risk factors associated with Theileria parva seropositivity in a longitudinal calf study, Narok, Kenya |
| title_short | Morbidity, mortality, and risk factors associated with Theileria parva seropositivity in a longitudinal calf study, Narok, Kenya |
| title_sort | morbidity mortality and risk factors associated with theileria parva seropositivity in a longitudinal calf study narok kenya |
| topic | Theileria parva Seropositivity Incidence Risk factors Calves |
| url | http://www.sciencedirect.com/science/article/pii/S2451943X25000328 |
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