Novel Bunyavirus in Domestic and Captive Farmed Animals, Minnesota, USA

Zheng Xing

, Jeremy Schefers, Marc Schwabenlander, Yongjun Jiao, Mifang Liang, Xian Qi, Chuan Li, Sagar Goyal, Carol J. Cardona, Xiaodong Wu, Zerui Zhang, Dexin Li, James Collins, and Michael P. Murtaugh

Author affiliations: College of Veterinary Medicine, University of Minnesota—Twin Cities, St. Paul, Minnesota, USA. (Z. Xing, J. Schefers, M. Schwabenlander, S. Goyal, C.J. Cardona, J. Collins, M.P. Murtaugh); Jiangsu Provincial Center for Disease Prevention and Control, Nanjing, China (Y. Jiao, X. Qi); Chinese Center for Disease Control and Prevention, Beijing, China (M. Liang, C. Li, D. Li); Medical School and State Key Laboratory of Pharmaceutical Biotechnology–Nanjing University, Nanjing (Z. Xing, X. Wu, Z. Zhang)

Abstract

We tested blood samples from domestic and captive farmed animals in Minnesota, USA, to determine exposure to severe fever with thrombocytopenia syndrome virus and Heartland-like virus. We found antibodies against virus nucleoproteins in 10%–18% of samples from cattle, sheep, goats, deer, and elk in 24 Minnesota counties.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease in China, caused by a novel bunyavirus in the genus Phlebovirus (1). As many as 10,000 SFTS case-patients have been reported since disease emergence in 2009, with fatality rates ranging from 2% to 15% (1,2), mainly in the eastern provinces of China. SFTS bunyavirus (STFSV) appears to be transmitted by ticks, an unusual difference from other pathogenic phleboviruses, which are transmitted primarily by mosquitoes (3). Recently, a new phlebovirus, named the Heartland virus (HLV), was isolated in Missouri from patients with a history of tick bites and signs and symptoms similar to those of SFTS, including high fever and low blood leukocyte and platelet counts (4). Phylogenetic analysis showed that HLV is closely related to SFTSV, which suggests that this new phlebovirus could be a serious threat to public health in the United States.
Many bunyaviruses can infect animals (3). Little is known about the animal host species that carry HLV or HLV-like bunyaviruses in the United States. Serologic surveys in China found that farm animals, including cattle, goats, and sheep, were infected with SFTSV in disease-endemic areas. In these studies, viral RNA was identified in animal serum specimens, and these isolates shared high sequence homology with isolates from humans (5). Strikingly, up to 47% of farm animals in Jiangsu Province, China, had SFTSVs (4), indicating that active virus transmission is occurring in the rapidly expanding disease-endemic area. It is critical to identify animal hosts that may be susceptible to, and infected with, HLV or an SFTSV-like virus, and may serve as amplifying hosts that facilitate virus transmission in the United States. To identify animal hosts that may play an essential role in transmission of SFTSV- or HLV-like viruses in the United States, we conducted serologic testing of samples collected from farm animals in Minnesota, USA. Our findings raise the specter of widespread distribution of a novel pathogen among livestock and wildlife that has the potential to be transmitted to humans.