Detecção de Anaplasma marginale por pesquisa de IgG e PCR em um rebanho bovino da Baixada Fluminense

Abstract

Activities in high productivity systems to dairy cattle contribute to imbalance health and disease, and increase the possibility of illness compatible with the infestation and infections transmitted by arthropods vectors. The objectives were to evaluate the prevalence and the seroepidemiological condition for Anaplasma marginale in 41calves from birth to completed 180 days. The animals belonged to “Centro Estadual de Pesquisa em Agricultura Orgânica” – Pesagro-Rio, Seropédica-RJ. There are few reports of molecular diagnostic techniques for this agent. The study was conducted during the rainy and dry seasons and collected a total of 1607 blood samples, initially every three days and processed using indirect ELISA test and PCR. Percent values for A. marginale seroprevalence as function of age were tested using the χ2 test at 5% significance level. The prevalence of anti-A. marginale antibodies were 39.8% in calves aged less than 30 days, 23.3% between 30 and 60 days, 27.3% between 60 and 120 days and 38.2% between 120 and 180 days, with 31.4% for samples of all age group (180 days). Calves aged between 30 and 60, 60 and 120 and 120 and 180 days were respectively 1.90, 1.75 and 1.55 more likely to be seronegative for A. marginale than newborn ones. All calves were positive to PCR until 13 days old. The values show that during the study calves had low levels of antibodies to A. marginale, a condition that predisposes them to the development of clinical anaplasmosis. In addition, the herd was considered unstable epidemiologically to A. marginale infection. The results show that animals had low antibody titers of IgG anti-A. marginale, being more susceptible to develop clinical anaplasmosis from 30 to 60 days. The results of the PCR method confirmed A. marginale in all animals before they are 15 days old and suggest the possibility of transplacental transmission occurs in the herd.