105 Tropical Biomedicine 30(1): 105–112 (2013) Bovine carriers of Anaplasma marginale and Anaplasma bovis in South India Nair, A.S. 1 , Ravindran, R. 2* , Lakshmanan, B. 2 , Sreekumar, C. 3 , Kumar, S.S. 2 , Remya Raju 4 , Tresamol, P.V. 1 , Vimalkumar, M.B. 2 and Saseendranath, M.R. 1 1 Department of Veterinary Epidemiology and Preventive Medicine, College of Veterinary and Animal Sciences, Mannuthy, Thrissur, Kerala 2 Department of Veterinary Parasitology, College of Veterinary and Animal Sciences, Pookode, Lakkidi, P. O., Wayanad, Kerala-673576 3 Department of Veterinary Parasitology, Tamil Nadu Veterinary and Animal Sciences University, Chennai 4 Department of Statistics, College of Veterinary and Animal Sciences, Pookode, Lakkidi, P. O., Wayanad, Kerala-673576 * Corresponding author email: drreghuravi@yahoo.com Received 13 March 2012; received in revised form 15 December 2012; accepted 12 January 2013 Abstract. Carriers of bovine anaplasmosis in Northern Kerala, South India were detected using conventional microscopical and molecular techniques. PCR-RFLP and nested PCR techniques were used for detection of Anaplasma marginale and Anaplasma bovis respectively and the PCR products were confirmed by sequencing. Out of 150 samples tested, 25 were detected positive for A. marginale and five for A. bovis based on molecular tests. The inclusion bodies of A. marginale could be detected by microscopy in two blood smears after staining by giemsa while acridine orange staining detected three smears positive. The data clearly suggest the higher sensitivity of molecular techniques for diagnosis of these diseases. INTRODUCTION Bovine anaplasmosis or gall sickness caused by the intraerythrocytic rickettsia, Anaplasma marginale (Rickettsiales: Anaplasmatacea) is transmitted biologically by infected ticks or mechanically by biting flies and contaminated fomites (Ristic, 1981). Acute anaplasmosis is characterized by fever, progressive haemolytic anemia, weight loss, abortion and even death resulting in significant loss to meat and milk production (Alderink & Dietrich, 1981). The economic loss due to infections caused by Babesia and Anaplasma infections in India was estimated to be $57 million (Tick Cost Version, 1.0, 1999). The genus Anaplasma also includes Anaplasma bovis, formerly referred as Ehrlichia bovis (Dumler et al ., 2001). Anaplasma bovis is transmitted by Rhipicephalus appendiculatus, Amblyomma variegatum and Hyalomma truncatum and occur in India and Africa (Radostits et al., 2000). The symptoms of bovine ehrlichiosis include fever, enlargement of peripheral lymphnodes, apathy, anorexia, loss of weight, shaking of head and in most of the cases one or both ears held over the parotid region with tilting of head towards that side (Woldehiwet & Ristic, 1993). Animals that recover from primary attack remain as life long carriers (Piercy, 1956). During the carrier stage, rickettsaemia occurs, which may permit vector transmission to take place and hence diagnosis of carrier status is important. Routine laboratory diagnosis in acutely infected cattle is based on the microscopic examination of peripheral blood smears. Serological tests even though developed, lack the required specificity and sensitivity for a