Tick-borne diseases in asymptomatic cattle from São Miguel Island, Azores – A clinical perspective

Abstract

Tick-borne diseases in asymptomatic cattle from São Miguel Island, Azores – A clinical perspective

Introduction/Background: The Azores archipelago is one of the regions with the highest cattle production, in Portugal. Outbreaks of tick-borne (TB) diseases have been reported by local field veterinarians and different tick species are described in São Miguel. At this study, we decided to investigate the presence of some of these agents in asymptomatic cattle, in S. Miguel. Materials & methods: In October 2019, 10 blood samples from each of 10 farms were randomly selected. Species belonging to the Babesia/Theileria and Anaplasma/ Ehrlichia genus were tested by PCR screening. Results: There were 45 positive samples later confirmed as species belonging to the Theileria orientalis group (45/100, 45%), in 9 farms (9/10, 90%) and it was also possible to identify Anaplasma bovis, in 2 animals, at two farms (2/10, 20%). Discussion: As far as we were able to verify, this is the first reference to the presence of these agents in S. Miguel. However, although asymptomatic, the repercussions associated with these infections are probably being underestimated or confused with other health problems. Since ixodids were not found in cows, other factors may be contributing to the high percentage of positive samples found, such as poor management practices. This is clearly an interesting subject for further investigation, as a better understanding of the life cycle of these parasites will contribute to their control.