Distribution of <i>Haemaphysalis longicornis</i> and Its Infected Agents: A Pooled Analysis of China Field Survey and Global Published Data

Abstract

Background: Haemaphysalis longicornis, a vector of various diseases with medical and veterinary importance, is native to eastern Asia, and recently invaded the United States as an emerging disease threat. Methods: We collected multi-source data from field survey, reference book, literature search and related websites. Geographic distribution of H. longicornis and its infected agents was mapped by geographical information system techniques. Hosts of H. longicornis and infection rates of H. longicornis-borne agents were estimated by meta-analysis. Ecological niche model was used to predict potential distribution of H. longicornis around the world. Findings: H. longicornis was broadly distributed in ten countries, predominantly in eastern Asia, the United States, and countries in the southwest Pacific Ocean. The tick was known to feed on a variety of domestic and wild animals. Nearly 60 agents, including spotted fever group rickettsiae, Anaplasmataceae family, Borrelia burgdorferi sensu lato, Babesia, Theileria, Francisella, Bartonella, Coxiella, Hepatozoon, Toxoplasma, and viruses were detected in H. longicornis, over half of which were pathogenic to humans. H. longicornis-borne agents were mainly reported in eastern Asia. The predictive modeling revealed that H. longicornis might infest more extensive regions, unexpectedly in Europe, South America, and Africa. Interpretation: H. longicornis is widely distributed in the world, and infected with various pathogens. Authorities and health care workers should be aware of the threat of the tick species to public health and veterinary medicine. Expanding surveillance and further investigations should be enhanced. Funding Statement: This study was supported by the Natural Science Foundation of China (81621005) and National Key Research and Development Program of China (2019YFC1200505). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: Not required.