Molecular detection of Anaplasma spp. in blood and milk of dairy cattle in the Philippines

Anaplasmosis has become a major concern in the cattle industry throughout the world due to its great economic impact. The causative agents, Anaplasma species, are primarily transmitted by ticks, occurring intracellularly within blood cells, with some species being zoonotic. In this study, the presence of Anaplasma spp. was investigated in the blood and milk of dairy cattle in the Philippines. Blood and milk samples were collected from 98 dairy cattle from selected farms in five provinces in the southern part of Luzon Island in the Philippines. After DNA extraction, a conventional PCR for the control gene actin was performed, followed by nested PCR for Anaplasma spp. Selected amplicons were purified and subjected to sequence analysis. It was found that 97 (98.97%) blood samples and 6 (6.12%) milk samples were positive for Anaplasma. Sequence analysis revealed that the positive amplicons from milk samples and their corresponding blood samples shared a high identity (98%-100%) with reported Anaplasma marginale isolates. To the authors' knowledge, this study provides the first molecular evidence of the presence of A. marginale in milk from dairy cattle under field conditions in the Philippines.