Epidemiology of Theileria annulata Infection of Dairy Cattle in the Sudan Using Molecular Techniques AWADIA M. ALI,a MOHAMMED A. BAKHEIT,a MAOWIA M. MUKHTAR,b SHAWGI M. HASSAN,a JABBAR S. AHMED,c AND ULRIKE SEITZERc a Faculty
of Veterinary Medicine, University of Khartoum, 13314 Khartoum North, Sudan b Institute
of Endemic Diseases, University of Khartoum, 11115 Khartoum North,
Sudan c Research
Center Borstel, 23845 Borstel, Germany
ABSTRACT: This study provides the first epidemiological data regarding T. annulata infection of diary cattle in Sudan using a combination of routine microscopic examination and two molecular techniques, PCR and reverse line blot (RLB). KEYWORDS: Theileria annulata; epidemiology; Sudan
INTRODUCTION In the Sudan tropical theileriosis has been recorded since 1908 and is considered the most important tick-borne disease with substantial economic impact. The epidemiological data of Theileria annulata infection by serological surveys showed that the prevalence decreased from 90% in Khartoum State to 13% in the southern parts of the Blue Nile. The aim of this article was to apply molecular techniques to determine the prevalence of T. annulata and other hemoparasite infections in the Sudan.
METHODS Samples (n = 162) were analyzed by a combination of routine stained blood smears and two molecular techniques, polymerase chain reaction (PCR) Address for correspondence: Ulrike Seitzer, Division of Veterinary Infectiology and Immunology, Research Center Borstel, Parkallee 22, 23845 Borstel, Germany. Voice: +49-4537-188-413; fax: +494537-188-627. e-mail:
[email protected] C 2006 New York Academy of Sciences. Ann. N.Y. Acad. Sci. 1081: 471–472 (2006). doi: 10.1196/annals.1373.068
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ANNALS NEW YORK ACADEMY OF SCIENCES
and reverse line blot (RLB). PCR was performed to specifically detect all Theileria spp.1 and T. annulata.2 RLB analysis was designed to detect all Ehrlichia/Anaplasma3 and Theileria/Babesia4 infections, as well as to specifically detect 4 Anaplasma, 4 Ehrlichia, 6 Babesia, and 9 Theileria species infecting ruminants.3–6
RESULTS AND DISCUSSION Piroplasms were detected in 16.7% of the animals using stained blood smears, 48.1% animals were positive by PCR, and 65.4% animals were positive by RLB. The agreement between the two molecular tests was 73.4%. The higher positive samples detected by molecular techniques indicate the carrier status of most of the studied animals. RLB allowed the detection of tick-borne parasites that simultaneously infected the animals. Analysis of the field samples also revealed that there may be a new species of Babesia and Ehrlichia/Anaplasma in the field, which needs to be confirmed by 18 S and 16 S rRNA gene analysis, respectively.
ACKNOWLEDGMENTS This research was partially supported by the Animal Resources Bank, Sudan, IAEA (NO. SUD04/027), the European Union (ICA4-2000-30028), and the German Academic Exchange Services (A.M. Ali).
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