Molecular evidence of transplacental transmission of Anaplasmamarginale in zebu neonatal calves of Venezuela

Anaplasma marginale is the most prevalent protobacteria in cattle worldwide. This pathogen multiplies in the erythrocytes and endothelium causing a hemolytic disease called anaplasmosis, which in its acute phase is accompanied by anemia, weight loss and even death. It is assumed that the organism is transmitted biologically by ixodides, mechanically by haematophagous dipterans, iatrogenically or by transplacental transmission. In order to detect neonatal anaplasmosis in a Brahman herd of the Yaracuy State, Venezuela, blood samples were collected from 29 calves less than 24 hours old and their postpartum mothers. The DNA obtained from 58 samples was subjected to a nested PCR (nPCR) specifi c for the diagnosis of Anaplasma spp. In addition the serum of the 29 mothers was evaluated by a competitive ELISA (ELISAc) for diagnosis of anaplasmosis using the protocol indicated by the commercial house VMRD. The results showed that in 20.69% of the offspring (6 calves) gene amplifi cation was obtained from msp5 of Anaplasma spp, while all the samples from the mothers were positive for nPCR and ELISAc. The experimental evidence obtained indicates that the presence of protobacteria in animals less than 24 hours of birth is the result of transplacental transmission from the infected mother to the fetus during pregnancy and shows that under the studied conditions this route of transmission is important in the spread of the pathogen.