Molecular, serological and parasitological survey of Theileria annulata in North Kordofan State, Sudan.

Abstract

This survey was conducted to detect Theileria annulata infection in indigenous (Zebu) and cross (indigenous × Friesian) cattle (n 604) of different sex & age groups, and to investigate prevalence of ticks infesting cattle in North Kordofan State, Sudan. Ticks, blood smears, serum samples and blood spots on filter paper were collected from four municipalities at four monthly intervals during the period from August 2008 to July 2009. Out of 604 blood smears, 69 (11.4%, 95% CI: 16.9-5.9) were positive for Theileria piroplasms; whereas, out of 240 serum samples, 164 (68.3%, 95% CI: 89.3-47.3) were positive for antibodies against T. annulata using IFA test. Using PCR, out of 100 blood spots on filter paper, 8 (8%, 95% CI: 9.6-6.4) revealed T. annulata DNA. The highest prevalence of Theileria spp. piroplasms and T. annulata antibodies was recorded in August (15.9 ± 4.6) followed by February (13.3 ± 3.8) and the lowest was in May (3.9 ± 1.0). Among cattle breeds, the highest prevalence of piroplasms (11.9 ± 5.0) and T. annulata antibodies (68.9 ± 10) was among zebu cattle. PCR assays revealed the highest prevalence rate of T. annulata DNA in February (12.5 ± 1.4) followed by August (6.1 ± 0.7) and the lowest was in May (5.7 ± 0.7). According to cattle breeds, T. annulata DNA was detected in cross-bred cattle (3.3 ± 0.4) more than zebu cattle (10 ± 1.6). Seven tick species belonging to four genera and were identified, Amblyomma lepidum, Hyalomma dromedarii, H. impeltatum, H. rufipes, Rhipicephalus evertsi evertsi, Rhipicephalus decoloratus, R. annulatus. The most abundant tick species was H. rufipes followed by H. impeltatum, R. e. evertsi, H. dromedarii, R. decoloratus, A. lepidum and R. annulatus. Theileria annulata has been detected for the first time in North Kordofan State, though at a low prevalence rate. This finding is an alarming situation since tropical theileriosis is an emerging disease and it is widely believed that this economically important tick-borne parasite does not exist in this state. The possible alternative vector(s) of T. annulata in the absence of the known vector H. anatolicum is discussed.