A cross-sectional survey to establish Theileria parva prevalence and vector control at the wildlife-livestock interface, Northern Tanzania

Allan, F. K. et al. (2021) A cross-sectional survey to establish Theileria parva prevalence and vector control at the wildlife-livestock interface, Northern Tanzania. Preventive Veterinary Medicine, 196, 105491. (doi: 10.1016/j.prevetmed.2021.105491) (PMID:34562810) (PMCID:PMC8573586)

Abstract

East Coast fever (ECF) in cattle is caused by the protozoan parasite Theileria parva, transmitted by Rhipicephalus appendiculatus ticks. In cattle ECF is often fatal, causing annual losses >$500 million across its range. The African buffalo (Syncerus caffer) is the natural host for T. parva but the transmission dynamics between wild hosts and livestock are poorly understood. This study aimed to determine the prevalence of T. parva in cattle, in a 30 km zone adjacent to the Serengeti National Park, Tanzania where livestock and buffalo co-exist, and to ascertain how livestock keepers controlled ECF and other vector-borne diseases of cattle. A randomised cross-sectional cattle survey and questionnaire of vector control practices were conducted. Blood samples were collected from 770 cattle from 48 herds and analysed by PCR to establish T. parva prevalence. Half body tick counts were recorded on every animal. Farmers were interviewed (n = 120; including the blood sampled herds) using a standardised questionnaire to obtain data on vector control practices. Local workshops were held to discuss findings and validate results. Overall prevalence of T. parva in cattle was 5.07% (CI: 3.70-7.00%), with significantly higher prevalence in older animals. Although all farmers reported seeing ticks on their cattle, tick counts were very low with 78% cattle having none. Questionnaire analysis indicated significant acaricide use with 79% and 41% of farmers reporting spraying or dipping with cypermethrin-based insecticides, respectively. Some farmers reported very frequent spraying, as often as every four days. However, doses per animal were often insufficient. These data indicate high levels of acaricide use, which may be responsible for the low observed tick burdens and low ECF prevalence. This vector control is farmer-led and aimed at both tick- and tsetse-borne diseases of livestock. The levels of acaricide use raise concerns regarding sustainability; resistance development is a risk, particularly in ticks. Integrating vaccination as part of this community-based disease control may alleviate acaricide dependence, but increased understanding of the Theileria strains circulating in wildlife-livestock interface areas is required to establish the potential benefits of vaccination.

• Item Type: Articles
• Additional Information: FKA was funded by a KTN/BBSRC iCASE PhD studentship, in partnership with the Global Alliance for Veterinary Medicines (GALVmed) with funding from Bill & Melinda Gates Foundation (Investment ID OPP1176784) and UKAID (Project 300504). S.J.T., L.J.M., H.K.A., J.S.L., R.S.L., F.M. and E.P. were also supported by a grant from the Zoonosis and Emerging and Livestock Systems (ZELS) programme (BB/L019035/1). L.J.M., W.I.M., E.P., F.K.A. and the Roslin Institute were supported by a core grant from the UK Biotechnology and Biological Sciences Research Council (BBS/E/D/20231762; BBS/E/D/20002173).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Auty, Harriet and Morrison, Dr Liam
• Authors: Allan, F. K., Sindoya, E., Adam, K. E., Byamungu, M., Lea, R. S., Lord, J. S., Mbata, G., Paxton, E., Mramba, F., Torr, S. J., Morrison, W. I., Handel, I., Morrison, L. J., and Auty, H. K.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity; College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Preventive Veterinary Medicine
• Publisher: Elsevier
• ISSN: 0167-5877
• ISSN (Online): 1873-1716
• Published Online: 11 September 2021
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Preventive Veterinary Medicine 196: 105491
• Publisher Policy: Reproduced under a Creative Commons License