Experimental and Natural Infections of Goats with Severe Fever with Thrombocytopenia Syndrome Virus: Evidence for Ticks as Viral Vector

Yongjun Jiao; Xian Qi; Dapeng Liu; Xiaoyan Zeng; Yewu Han; Xiling Guo; Zhiyang Shi; Hua Wang; Minghao Zhou

doi:10.1371/journal.pntd.0004092

Experimental and Natural Infections of Goats with Severe Fever with Thrombocytopenia Syndrome Virus: Evidence for Ticks as Viral Vector

PLoS Negl Trop Dis. 2015 Oct 20;9(10):e0004092. doi: 10.1371/journal.pntd.0004092. eCollection 2015.

Authors

Yongjun Jiao¹, Xian Qi¹, Dapeng Liu¹, Xiaoyan Zeng¹, Yewu Han², Xiling Guo¹, Zhiyang Shi¹, Hua Wang¹, Minghao Zhou¹

Affiliations

¹ Institute of Pathogenic Microbiology, Jiangsu Provincial Center for Disease Prevention and Control, Key Laboratory of Enteric Pathogenic Microbiology, Ministry Health, Nanjing, China.
² Xuyi County Center for Disease Prevention and Control, Huai-an, China.

Abstract

Background: Severe fever with thrombocytopenia syndrome virus (SFTSV), the causative agent for the fatal life-threatening infectious disease, severe fever with thrombocytopenia syndrome (SFTS), was first identified in the central and eastern regions of China. Although the viral RNA was detected in free-living and parasitic ticks, the vector for SFTSV remains unsettled.

Methodology/principal findings: Firstly, an experimental infection study in goats was conducted in a bio-safety level-2 (BSL-2) facility to investigate virus transmission between animals. The results showed that infected animals did not shed virus to the outside through respiratory or digestive tract route, and the control animals did not get infected. Then, a natural infection study was carried out in the SFTSV endemic region. A cohort of naïve goats was used as sentinel animals in the study site. A variety of daily samples including goat sera, ticks and mosquitoes were collected for viral RNA and antibody (from serum only) detection, and virus isolation. We detected viral RNA from free-living and parasitic ticks rather than mosquitoes, and from goats after ticks' infestation. We also observed sero-conversion in all members of the animal cohort subsequently. The S segment sequences of the two recovered viral isolates from one infected goat and its parasitic ticks showed a 100% homology at the nucleic acid level.

Conclusions/significance: In our natural infection study, close contact between goats does not appear to transmit SFTSV, however, the naïve animals were infected after ticks' infestation and two viral isolates derived from an infected goat and its parasitic ticks shared 100% of sequence identity. These data demonstrate that the etiologic agent for goat cohort's natural infection comes from environmental factors. Of these, ticks, especially the predominant species Haemaphysalis longicornis, probably act as vector for this pathogen. The findings in this study may help local health authorities formulate and focus preventive measures to contain this infection.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Arachnid Vectors*
Bunyaviridae Infections / veterinary*
Goat Diseases / etiology*
Goats
Phlebovirus / isolation & purification*
RNA, Viral / analysis
Ticks / virology*

Substances

RNA, Viral

Grants and funding

For the financial support of this study, YJ received funding from Jiangsu Science and Technology Department (Jiangsu Province community development project, BE2012768. www.jstd.gov.cn); Jiangsu Provincial Commission of Health and Family Planning (Jiangsu Province Outstanding Medical Academic Leader Program, RC2011082, www.jswst.gov.cn); Ministry of Science and Technology People's Republic of China (National Mega-Project for Infectious Diseases, 2013ZX09102029, www.most.gov.cn); and National Natural Science Foundation grant number 31570926. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.