Anaplasma marginale transplacental transmission in a calf: clinical, anatomopathological, and molecular reports

Abstract

Bovine anaplasmosis is caused by obligate intracellular rickettsia Anaplasma marginale transmitted by ticks Rhipicephalus microplus, hematophagous flies, and/or iatrogenically. Transplacental transmission is possible but sub-reported. In this context, the present work aimed to report a case of a calf that was born with anemia, jaundice, and neurological problems. A calf blood smear showed intraerythrocytic inclusion of A. marginale. Accordingly, the animal was treated with oxytetracycline but died three days after the start of treatment. The necropsy revealed conjunctival and subcutaneous jaundice, splenic congestion and distension, and an intensely yellow liver were noted. Histopathology showed moderate, multifocal hepatocellular degeneration, diffuse and marked cholestasis, and histiocytic necrotizing encephalitis. A. marginale infection was confirmed by PCR, and real-time PCR (qPCR). qPCR analysis showed that 3.3% of the erythrocytes in the calf's blood sample were parasitized. Thus, here we report a case of transplacental transmission A. marginale in a newborn calf.