First Report on Transplacental Transmission of Anaplasma marginale in Neonatal Dairy Calves from District Jhang, Punjab, Pakistan

Abstract

The current study was planned to evaluate the transplacental transmission potentials of Anaplasma marginale among naturally infected adult dairy cattle in district Jhang, Punjab, Pakistan. A dairy farm was selected after a district level survey having highest number of blood smear, cELISA and PCR positives of A. marginale infected pregnant crossbred cows (Holstein Friesian × Cholistani). Blood samples were collected from dams (within 4 months of their pregnancies and at the time of parturitions) as well as from the new-born calves (before colostrum feeding within 3 h of the birth). Eighty pregnant cows were screened through the cELISA and PCR. Out of these, 54 were found positive for anaplasmosis. Further follow up revealed that 38 cows remained positive at the time of parturition. Finally, based on the criteria, 32 calves without colostrum feeding qualified for the vertical transmission trial. The results of present study revealed that 28 (9/32) and 13% (4/32) of the neonatal calves acquired intrauterine infection confirmed by cELISA and PCR, respectively. Overall occurrence of the transplacental transmission was 31%. Nevertheless, we concluded that transplacental transmission occurs and this route of transmission, can lead to a significant number of neonatal deaths. Hence, the transplacental route of disease transmission should also be considered for devising the prevention and control strategies regarding anaplasmosis in the dairy cattle.