The sero-epidemiology of Neospora caninum in cattle in northern Tanzania

Semango, G. et al. (2019) The sero-epidemiology of Neospora caninum in cattle in northern Tanzania. Frontiers in Veterinary Science, 6, 327. (doi: 10.3389/fvets.2019.00327) (PMID:31681800) (PMCID:PMC6798052)

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Neospora caninum is a protozoan intracellular parasite of animals with a global distribution. Dogs act as definitive hosts, with infection in cattle leading to reproductive losses. Neosporosis can be a major source of income loss for livestock keepers, but its impacts in sub-Saharan Africa are mostly unknown. This study aimed to estimate the seroprevalence and identify risk factors for N. caninum infection in cattle in northern Tanzania, and to link herd-level exposure to reproductive losses. Serum samples from 3,015 cattle were collected from 380 households in 20 villages between February and December 2016. Questionnaire data were collected from 360 of these households. Household coordinates were used to extract satellite derived environmental data from open-access sources. Sera were tested for the presence of N. caninum antibodies using an indirect ELISA. Risk factors for individual-level seropositivity were identified with logistic regression using Bayesian model averaging (BMA). The relationship between herd-level seroprevalence and abortion rates was assessed using negative binomial regression. The seroprevalence of N. caninum exposure after adjustment for diagnostic test performance was 21.5% [95% Credibility Interval (CrI) 17.9–25.4]. The most important predictors of seropositivity selected by BMA were age greater than 18 months [Odds ratio (OR) = 2.17, 95% CrI 1.45–3.26], the local cattle population density (OR = 0.69, 95% CrI 0.41–1.00), household use of restricted grazing (OR = 0.72, 95% CrI 0.25–1.16), and an increasing percentage cover of shrub or forest land in the environment surrounding a household (OR = 1.37, 1.00–2.14). There was a positive relationship between herd-level N. caninum seroprevalence and the reported within-herd abortion rate (Incidence Rate Ratio = 1.03, 95% CrI 1.00–1.06). Our findings suggest N. caninum is likely to be an important cause of abortion in cattle in Tanzania. Management practices, such as restricted grazing, are likely to reduce the risk of infection and suggest contamination of communal grazing areas may be important for transmission. Evidence for a relationship between livestock seropositivity and shrub and forest habitats raises questions about a potential role for wildlife in the epidemiology of N. caninum in Tanzania.

Item Type:Articles
Glasgow Author(s) Enlighten ID:De Glanville, Dr William and Kreppel, Dr Katharina and Allan, Dr Kathryn and Cleaveland, Professor Sarah and Lankester, Dr Felix and Claxton, Dr John and Thomas, Dr Kate
Authors: Semango, G., Hamilton, C. M., Kreppel, K., Katzer, F., Kibona, T., Lankester, F., Allan, K. J., Thomas, K. M., Claxton, J. R., Innes, E. A., Swai, E. S., Buza, J., Cleaveland, S., and de Glanville, W. A.
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:Frontiers in Veterinary Science
Publisher:Frontiers Media
ISSN (Online):2297-1769
Copyright Holders:Copyright © 2019 Semango, Hamilton, Kreppel, Katzer, Kibona, Lankester, Allan, Thomas, Claxton, Innes, Swai, Buza, Cleaveland and de Glanville
First Published:First published in Frontiers in Veterinary Science 6: 327
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
627871Social, economic and environmental drivers of zoonoses in Tanzania (SEEDZ)Sarah CleavelandBiotechnology and Biological Sciences Research Council (BBSRC)BB/L018926/1RI BIODIVERSITY ANIMAL HEALTH & COMPMED
173142African Science Partnership for Intervention Research Excellence (Afrique One-ASPIRE)Daniel HaydonWellcome Trust (WELLCOTR)107753/B/15/ZInstitute of Biodiversity, Animal Health and Comparative Medicine