Antigens and Alternatives for Control ofAnaplasma marginaleInfection in Cattle

Abstract

Anaplasmosis, a tick-borne cattle disease caused by the rickettsia Anaplasma marginale, is endemic in tropical and subtropical areas of the world. The disease causes considerable economic loss to both the dairy and beef industries worldwide. Analyses of 16S rRNA, groESL, and surface proteins have resulted in the recent reclassification of the order Rickettsiales. The genus Anaplasma, of which A. marginale is the type species, now also includes A. bovis, A. platys, and A. phagocytophilum, which were previously known as Ehrlichia bovis, E. platys, and the E. phagocytophila group (which causes human granulocytic ehrlichiosis), respectively. Live and killed vaccines have been used for control of anaplasmosis, and both types of vaccines have advantages and disadvantages. These vaccines have been effective in preventing clinical anaplasmosis in cattle but have not blocked A. marginale infection. Thus, persistently infected cattle serve as a reservoir of infective blood for both mechanical transmission and infection of ticks. Advances in biochemical, immunologic, and molecular technologies during the last decade have been applied to research of A. marginale and related organisms. The recent development of a cell culture system for A. marginale provides a potential source of antigen for the development of improved killed and live vaccines, and the availability of cell culture-derived antigen would eliminate the use of cattle in vaccine production. Increased knowledge of A. marginale antigen repertoires and an improved understanding of bovine cellular and humoral immune responses to A. marginale, combined with the new technologies, should contribute to the development of more effective vaccines for control and prevention of anaplasmosis

Detection and phylogenetic characterization of Theileria spp. and Anaplasma marginale in Rhipicephalus bursa in Portugal

“…Bovine anaplasmosis is now known to be endemic in tropical and subtropical regions worldwide, causing substantial economic losses to cattle industries (Kocan et al, 2003). T. annulata is mainly transmitted by ticks of the genus Hyalomma; however, similarly to our study, R. bursa was also associated with the transmission of this pathogen in Tunisia (M'Ghirbi et al, 2010).…”

Molecular and serological prevalence of Anaplasma marginale in cattle of North Central Morocco

“…Following transmission, cattle develop rickettsiaemia, accompanied by fever, severe anemia, weight loss, decreased milk production, abortion and sometimes death during acute infections (Kocan et al, 2003;Urdaz-Rodríguez et al, 2009). After the first infection with A. marginale, cattle remain persistently infected carriers and serve as long-term reservoirs for the maintenance of the infection in ticks (Goff et al, 1988;Kocan et al, 1992a,b;Eriks et al, 1993).…”

Molecular diagnosis of Anaplasma marginale in cattle: quantitative evaluation of a real-time PCR (Polymerase Chain Reaction) based on msp5 gene

“…Anaplasma marginale is an obligate intracellular pathogen belonging to the genus Anaplasma (Order Rickettsiales, Family Anaplasmataceae) which causes anaplasmosis in bovines (Theiler 1910, Dumler et al 2001, Kocan et al 2003). This rickettsia is transmitted biologically by ixodid ticks.…”