Molecular detection of Mycoplasma ovis in an outbreak of hemolytic anemia in sheep from Veracruz, Mexico.

Mycoplasma ovis is a small, pleiotropic bacterium, which parasitizes the external surface of erythrocytes of several species of artiodactyl mammals, especially sheep and goats. We here report an outbreak of ovine mycoplasmosis in a sheep flock of a private ranch (Universidad Veracruzana) in Veracruz, Mexico. For the identification of Mycoplasma and other hemoparasitic bacterial agents, we stained blood smears with the DiffQuick® technique and additionally amplified several fragments of 16S rDNA gene. We detected the presence of morulas in erythrocytes from 30 sick female adult sheep, and found Mycoplasma ovis DNA in all of them. Furthermore, three of these animals also tested positive for Anaplasma ovis. Our findings represent the first record of M. ovis and A. ovis in an outbreak of hemolytic anemia in a sheep flock, leading to severe livestock loss in a ranch of Mexico. This study highlights the importance of establishing an active surveillance of both pathogens in the country.