Description of bovine babesiosis and anaplasmosis outbreaks in northern Uruguay between 2016 and 2018.

Abstract

Bovine babesiosis and anaplasmosis cause important economic losses in livestock production. In Uruguay, the main aetiological agents of bovine babesiosis and anaplasmosis are Babesia bovis, B. bigemina and Anaplasma marginale. The aim of this work was to describe the outbreaks of bovine babesiosis and anaplasmosis in northern Uruguay between 2016 and 2018. Convenience sampling was carried out. We worked with blood and organ samples from bovines with clinical signs and autopsy findings compatible with babesiosis and anaplasmosis. A total of 140 presumptive outbreaks were studied. Epidemiological information such as place, date of occurrence, age, number of sick and dead animals, clinical signs, autopsy findings, the presence of ticks and health management that involved injectables were registered. The diagnoses were carried out by blood and organ smears stained with Giemsa and confirmed by multiplex PCR. There were 83 (59.2%) positive outbreaks, comprising 35 (42.2%) A. marginale, 19 (22.9%) B. bigemina, 18 (21.7%) B. bovis and 11 (13.2%) mixed infections (Babesia spp. + A. marginale). Cows were the most commonly affected category. The clinical signs and autopsy findings with a significant association (p≤0.05) were anaemia, pale mucous membranes, fever, jaundice, ataxia and aggressiveness, splenomegaly, and orange discolouration of the liver. Babesiosis had a seasonal occurrence, mainly in autumn, while anaplasmosis cases were recorded throughout the year. The use of injectable agents was associated with A. marginale transmission. This work contributes updated information about epidemiological and clinical patterns of bovine babesiosis and anaplasmosis in northern Uruguay, which is important for implementing preventive measures and control.