A Disease Outbreak in Beef Cattle Associated with and Infections.

An outbreak of disease in a Swedish beef cattle herd initiated an in-depth study to investigate the presence of bacteria and viruses in the blood of clinically healthy ( = 10) and clinically diseased cattle ( = 20) using whole-genome shotgun sequencing (WGSS). The occurrence of infectious agents was also investigated in ticks found attached to healthy cattle ( = 61) and wild deer (n = 23), and in spleen samples from wild deer ( = 30) and wild boars ( = 10). Moreover, blood samples from 84 clinically healthy young stock were analysed for antibodies against and The WGSS revealed the presence of at least three distinct variants that were most closely related to . Two of these were very similar to a divergent variant previously only detected in Mexico. These variants tended to be more common in the diseased cattle than in the healthy cattle but were not detected in the ticks or wild animals. The DNA of was detected in similar proportions in diseased (33%) and healthy (40%) cattle, while 70% of the deer, 8% of ticks collected from the cattle and 19% of the ticks collected from deer were positive. Almost all the isolates from the cattle, deer and ticks belonged to Ecotype 1. Based on sequencing of the groEL-gene, most isolates of from cattle were similar and belonged to a different cluster than the isolates from wild deer. Antibodies against were detected in all the analysed samples. In conclusion, uncommon variants of were detected, probably associated with the disease outbreak in combination with immune suppression due to granulocytic anaplasmosis. Moreover, was found to be circulating within this cattle population, while circulation between cattle and deer occurred infrequently.