title: The epidemiology of tick-borne haemoparasites as determined by the reverse line blot hybridization assay in an intensively studied cohort of calves in western Kenya.
abstract: The development of sensitive surveillance technologies using PCR-based detection of microbial DNA, such as the reverse line blot assay, can facilitate the gathering of epidemiological information on tick-borne diseases, which continue to hamper the productivity of livestock in many parts of Africa and elsewhere. We have employed a reverse line blot assay to detect the prevalence of tick-borne parasites in an intensively studied cohort of indigenous calves in western Kenya. The calves were recruited close to birth and monitored for the presence of infectious disease for up to 51 weeks. The final visit samples from 453 calves which survived for the study period were analyzed by RLB. The results indicated high prevalences of Theileria mutans (71.6%), T. velifera (62.8%), Anaplasma sp. Omatjenne (42.7%), A. bovis (39.9%), Theileria sp. (sable) (32.7%), T. parva (12.9%) and T. taurotragi (8.5%), with minor occurrences of eight other haemoparasites. The unexpectedly low prevalence of the pathogenic species Ehrlichia ruminantium was confirmed by a species-specific PCR targeting the pCS20 gene region. Coinfection analyses of the seven most prevalent haemoparasites indicated that they were present as coinfections in over 90% of the cases. The analyses revealed significant associations between several of the Theileria parasites, in particular T. velifera with Theileria sp. sable and T. mutans, and T. parva with T. taurotragi. There was very little coinfection of the two most common Anaplasma species, although they were commonly detected as coinfections with the Theileria parasites. The comparison of reverse line blot and serological results for four haemoparasites (T. parva, T. mutans, A. marginale and B. bigemina) indicated that, except for the mostly benign T. mutans, indigenous cattle seem capable of clearing infections of the three other, pathogenic parasites to below detectable levels. Although the study site was located across four agroecological zones, there was little restriction of the parasites to particular zones.
authors: The International Livestock Research Institute, PO Box, 30709, 00100 Nairobi, Kenya; Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
authors: Nyawira E
authors: NE
authors: Njiiri
authors: The Roslin Institute, University of Edinburgh, Easter Bush, Edinburgh EH25 9RG, UK.
authors: B Mark deC
authors: BM
authors: Bronsvoort
authors: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
authors: Nicola E
authors: NE
authors: Collins
authors: Agricultural Research Council-Onderstepoort Veterinary Institute, Private Bag X05, Onderstepoort 0110, South Africa.
authors: Helena C
authors: HC
authors: Steyn
authors: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
authors: Milana
authors: M
authors: Troskie
authors: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
authors: Ilse
authors: I
authors: Vorster
authors: Centre for Immunity, Infection & Evolution, University of Edinburgh, Edinburgh EH9 3JT, UK; Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164-7090, USA.
authors: S M
authors: SM
authors: Thumbi
authors: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
authors: Kgomotso P
authors: KP
authors: Sibeko
authors: The Roslin Institute, University of Edinburgh, Easter Bush, Edinburgh EH25 9RG, UK; The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh EH25 9RG, UK.
authors: Amy
authors: A
authors: Jennings
authors: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
authors: Ilana Conradie
authors: IC
authors: van Wyk
authors: School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK; African Union InterAfrican Bureau for Animal Resources (AU-IBAR), PO Box 30786, 00100 Nairobi, Kenya.
authors: Mary
authors: M
authors: Mbole-Kariuki
authors: The International Livestock Research Institute, PO Box, 30709, 00100 Nairobi, Kenya.
authors: Henry
authors: H
authors: Kiara
authors: The International Livestock Research Institute, PO Box, 30709, 00100 Nairobi, Kenya.
authors: E Jane
authors: EJ
authors: Poole
authors: School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK.
authors: Olivier
authors: O
authors: Hanotte
authors: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
authors: Koos
authors: K
authors: Coetzer
authors: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
authors: Marinda C
authors: MC
authors: Oosthuizen
authors: Centre for Immunity, Infection & Evolution, University of Edinburgh, Edinburgh EH9 3JT, UK.
authors: Mark
authors: M
authors: Woolhouse
authors: The International Livestock Research Institute, PO Box, 30709, 00100 Nairobi, Kenya. Electronic address: p.toye@cgiar.org.
authors: Philip
authors: P
authors: Toye
mesh_terms: D000709:Anaplasma / Q000302:isolation & purification*; D000712:Anaplasmosis / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D000818:Animals; D001403:Babesia / Q000302:isolation & purification; D001404:Babesiosis / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D002417:Cattle; D060085:Coinfection; D016873:Ehrlichiosis / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000662:veterinary; D015151:Immunoblotting / Q000379:methods / Q000662:veterinary*; D007630:Kenya / Q000453:epidemiology; D016794:Theileria / Q000302:isolation & purification*; D013801:Theileriasis / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology
keywords: Anaplasma; Cattle; Coinfection; Haemoparasites; Reverse line blot; Theileria