Molecular, Serological and Parasitological Survey of Theileria Annulata in North Kordofan State, Sudan

Abstract

his study was conducted from August 2008 to July 2009 to detect Theileria annulata infection in cattle and to investigate prevalence of ticks infesting cattle in North Kordofan State. Ticks, blood smears, serum samples and blood spots on filter paper were collected from four localities namely Sheikan, Um Ruwaba, Abu Zabad and Elnohood at four monthly intervals for one year. In each locality samples were collected from 5 to 8 farms, set apart, and in each farm 5 to 8 head of cattle were sampled. Indigenous (Zebu) and cross (Friesian × indigenous) breeds of cattle were selected. Samples were collected from 604 heads of cattle of both sex and of different age groups, i.e. less than two years old calves, from 2 - 4 years old heifers or steers and older than four years cows or bulls. The same animals, whenever possible, were used during each collection. Four tick genera and seven species were identified. The genera were Amblyomma, Rhipicephalus (Boophilus), Hyalomma and Rhipicephalus. The tick species were Amblyomma lepidum, Rhipicephalus (Boophilus) decoloratus, R. (Boophilus) annulatus, Hyalomma dromedarii, H. impeltatum, H. rufipes, Rhipicephalus. evertsi evertsi. The most abundant tick species was H. rufipes followed by H. impeltatum, R. e. evertsi, H. dromedarii, R. (B.) decoloratus, A. lepidum and R. (B) annulatus. The highest mean tick load (0.6±0.12) for H. rufipes was in Um Ruwaba and Abu Zabad and (0.6±0.01) for H. dromedarii was in Um Ruwaba. Out of 604 blood smears, 69 (11.4%) were positive for Theileria spp. piroplasms with the highest prevalence rate in Um Ruwaba followed by Sheikan, El Nohood and the lowest was reported in Abu Zabad. Serologically, out of 240 164 (68.3%) serum samples were positive for T. annulata antibodies using IFA test with the highest rate in Sheikan followed by Um Ruwaba, Abu Please purchase PDFcamp Printer on http://www.verypdf.com/ to remove this watermark. xv Zabad and the lowest was in Elnohood. Using PCR, out of 100 8 (8%) blood spots were positive of T. annulata DNA with the highest prevalence rate in Abu Zabad followed by Sheikan, Elnohood and the lowest was in Um Ruwaba. The highest prevalence of Theileria spp. piroplasms and T. annulata antibodies was in August 2008 followed by February 2009, and the lowest was in May 2009. Among cattle breeds, the highest prevalence of piroplasms and T. annulata antibodies was found among Zebu cattle. The highest prevalence rate of Theileria spp. piroplasms was among cattle older than four years, followed by calves less than two years old, and the lowest was among cattle from two to four years old. The highest prevalence rate of T. annulata antibodies was among cattle from two to four years old, followed calves less than two years, and the lowest was among cattle older than four years. The highest prevalence rate of T. annulata DNA was during February 2009, followed by August 2008 and the lowest was in May 2009. According to cattle breed, PCR test showed that Zebu cattle were more infected than in cross bred. According to age, the highest infection rate was among cattle older than four years, followed by cattle from two to four years and the lowest was among calves less than two years old. It is concluded that T. annulata is detected in North Kordofan State, though at a low prevalence rate. This finding is an alarming situation since it is widely believed that this parasite does not occur in North Kordofan State. The possible vector of T. annulata in the absence of the known vector H. anatolicum is discussed.