title: Mixed Theileria infections in free-ranging buffalo herds: implications for diagnosing Theileria parva infections in Cape buffalo (Syncerus caffer).
abstract: Buffalo-adapted Theileria parva causes Corridor disease in cattle. Strict control measures therefore apply to the movement of buffalo in South Africa and include mandatory testing of buffalo for the presence of T. parva. The official test is a real-time hybridization PCR assay that amplifies the V4 hypervariable region of the 18S rRNA gene of T. parva, T. sp. (buffalo) and T. sp. (bougasvlei). The effect that mixed T. parva and T. sp. (buffalo)-like infections have on accurate T. parva diagnosis was investigated in this study. In vitro mixed infection simulations indicated PCR signal suppression at 100 to 1000-fold T. sp. (buffalo) excess at low T. parva parasitaemia. Suppression of PCR signal was found in field buffalo with mixed infections. The T. parva-positive status of these cases was confirmed by selective suppression of T. sp. (buffalo) amplification using a locked nucleic acid clamp and independent assays based on the p67, p104 and Tpr genes. The incidence of mixed infections in the Corridor disease endemic region of South Africa is significant, while the prevalence in buffalo outside the endemic area is currently low. A predicted increase of T. sp. (buffalo)-like infections can affect future diagnoses where mixed infections occur, prompting the need for improvements in current diagnostics.
authors.affiliation: Parasites, Vectors and Vector-Borne Diseases, Agricultural Research Council-Onderstepoort Veterinary Institute, Onderstepoort 0110, South Africa.
authors.forename: Ronel
authors.initials: R
authors.lastname: Pienaar
authors.affiliation: Parasites, Vectors and Vector-Borne Diseases, Agricultural Research Council-Onderstepoort Veterinary Institute, Onderstepoort 0110, South Africa.
authors.forename: Fred T
authors.initials: FT
authors.lastname: Potgieter
authors.affiliation: Parasites, Vectors and Vector-Borne Diseases, Agricultural Research Council-Onderstepoort Veterinary Institute, Onderstepoort 0110, South Africa.
authors.forename: Abdalla A
authors.initials: AA
authors.lastname: Latif
authors.affiliation: Parasitology Research Program, Department of Zoology and Entomology, University of the Free State Qwaqwa Campus, Private Bag X13, Phuthaditjhaba 9866, South Africa.
authors.forename: Oriel M M
authors.initials: OM
authors.lastname: Thekisoe
authors.affiliation: Parasites, Vectors and Vector-Borne Diseases, Agricultural Research Council-Onderstepoort Veterinary Institute, Onderstepoort 0110, South Africa.
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Mans
mesh_terms: D000818:Animals; D002020:Buffaloes / Q000469:parasitology*; D060085:Coinfection / Q000175:diagnosis / Q000453:epidemiology / Q000469:parasitology; D017125:Genes, Protozoan / Q000235:genetics; D005819:Genetic Markers / Q000235:genetics; D015994:Incidence; D018512:Parasitemia / Q000453:epidemiology / Q000662:veterinary*; D015995:Prevalence; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D013019:South Africa / Q000453:epidemiology; D016797:Theileria parva / Q000235:genetics / Q000502:physiology*; D013801:Theileriasis / Q000175:diagnosis* / Q000469:parasitology*
chemical_list: D005819:Genetic Markers; D012337:RNA, Ribosomal, 18S