Shkap, V., Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan, 50250, Israel
Kocan, K., Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, United States
Molad, T., Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan, 50250, Israel
Mazuz, M., Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan, 50250, Israel
Leibovich, B., Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan, 50250, Israel
Krigel, Y., Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan, 50250, Israel
Michoytchenko, A., Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan, 50250, Israel
Blouin, E., Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, United States
de la Fuente, J., Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, United States
Samish, M., Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan, 50250, Israel
Mtshali, M., National Zoological Gardens, P.O. Box 754, Pretoria, South Africa
Zweygarth, E., Onderstepoort Veterinary Institute, Private Bag X5, Onderstepoort, 0110, South Africa
Fleiderovich, E.L., Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan, 50250, Israel
Fish, L., Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan, 50250, Israel

The cattle rickettsia Anaplasma marginale is distributed worldwide and is transmitted by about 20 tick species, but only Rhipicephalus simus, a strictly African tick species, has been shown to transmit the vaccine strain of A. centrale. The aim of the present study was to examine transmission of field strains of A. marginale and of the vaccine strain of A. centrale by three tick species - Hyalomma excavatum, Rhipicephalus sanguineus and Rhipicephalus (Boophilus) annulatus - to susceptible calves. Two genetically distinct Israeli field strains of A. marginale, tailed and non-tailed (AmIsT and AmIsNT, respectively), were efficiently transmitted by R. sanguineus, whereas H. excavatum transmitted only the tailed isolate, and R. (Boophilus) annulatus did not transmit A. marginale. None of the three tick species transmitted A. centrale. By means of msp1a primers in PCR assays, amplicons of similar sizes were obtained from either A. marginale-infected calves that were used for acquisition feeding, from R. sanguineus fed on the infected calves, or from calves to which anaplasmosis had been successfully transmitted by these ticks. Although an A. centrale-specific fragment was amplified from salivary glands of R. sanguineus, no transmission to susceptible cattle occurred during 3 months of observation, and anaplasmosis was not induced in splenectomized calves that were subinoculated with blood from calves on which R. sanguineus had fed. © 2008 Elsevier B.V. All rights reserved.