Occurrence and transplacental transmission of anaplasma marginale in dairy cattle

Abstract

Bovine anaplasmosis, caused by Anaplasma marginale, is a non-contagious tick borne disease. The main objective of the current study was to investigate comparative frequency of anaplasmosis in three different cattle breeds (European breed/ Holstein Friesian and Jersey breed, indigenous breed and cross breed (1st and 2nd pedigree) and transplacental transmission using real time polymerase chain reaction for detection. Of the total 96 blood samples analyzed, our results indicated an overall incidence 45.83% (44/96) of A. marginale with highest incidence 62.5% (20/32) in European breed, followed by 42.4% (14/33) in cross breed and 35.4% (11/31) in indigenous breed. Most importantly, our results indicated that 13.7% (4/29) calves were found positive for the presence of A. marginale indicating transplacental transmission. Furthermore, indirect ELISA revealed an overall incidence rate of 34.3% (33/96) more likely indicating current or previous exposure. Finally, Giemsa staining determined that 15% (15/96) animals were found positive by examining red blood cells. Statistical analysis showed significantly higher (P<0.05) incidence of European breed as compared to crossbreed and indigenous breed of cattle, while non-significant (P>0.05) difference was found among the crossbred and indigenous breed of cattle. Moreover, non significant (P> 0.05) effect of age group was observed on the incidence of A. marginale. White blood cell count and mean corpuscular volume were significantly (P<0.05) higher in infected cattle, while, red blood cells, packed cell volume hemoglobin concentration, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration (MCHC) were significantly (P<0.05) higher in non-infected as compare to infected animals.