Comprehensive surveillance of bovine piroplasmosis in Bangladesh: Clinicopathology and molecular insights.

Abstract

Piroplasmosis, caused by Theileria and Babesia species, is an emerging threat to the health and productivity of cattle in Bangladesh. This study investigated clinical incidence of bovine piroplasms in commercial cattle farms across the country. A total of 480 clinically diseased cattle were examined for epidemiology, hematology and genetic profiling of piroplasms. PCR confirmed the morbidity rates 83.6% for theileriosis and 79.5% for babesiosis, respectively. Theileriosis was mostly found in Chattogram (89.47%), whereas babesiosis was predominantly recorded in Rajshahi and Mymensingh (90.9%) divisions. Mortality rates were 8.9% (32/360) for theileriosis and 9.16% (11/120) for babesiosis, with the highest in Mymensingh division, highlighting regional vulnerability. Mixed infection with Theileria and Babesia spp. was 18.18% of the positive cases, indicating the possible synergistic effects and clinical complexities. The common clinical signs of piroplasmosis were persistent fever, anemia, jaundice, with lymphadenopathy characteristic of theileriosis and pathognomonic hemoglobinuria for babesiosis. Hematology revealed the reduction of hemoglobin, packed cell volume, erythrocytes and platelet count, along with leukopenia. Seasonal variations, age, gender, breed, and tick infestation were identified as significant risk factors for occurrence of piroplasmosis. Phylogenetic analysis revealed that Theileria 18S rRNA clustered with T. orientalis from China and Babesia 18S rRNA with B. naoakii from Sri Lanka and Bangladesh. The phylogeny of spherical body protein (SBP4) gene was clustered with B. bovis reported from Tanzania. Future investigations into transmission dynamics, mixed infections and genetic diversity of parasites are recommended to strengthen effective control strategies.