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Prevalence of Borrelia Burgdorferi In Ixodidae Tick Vectors Around Asia: A Systematic Review and Meta-Analysis

Background: Lyme disease (LD) is a common arthropod-borne epidemic inflammatory disorder prevalent in northern hemisphere. LD is a multi-system disorder that is treatable with antibiotics, but may lead to severe complications of the neurological system, the heart, and the joints. LD is caused by a spirochete named Borrelia burgdorferi s.l., which is transmitted to humans by ticks. Climate, environment and other factors in different places affect land use and recreational behavior changes that affect human contact with infected ticks, thereby affecting the prevalence of diseases. Europe and North America have a lot of researches on this aspect, but Asia is lacking. 
 
Methods: We searched the PubMed, Excerpta Medica Database (Embase), the China National Knowledge Infrastructure (CNKI), and the Wanfang (China database) to identify all relevant abstracts published until March 2021. A meta-analysis was performed using the standard methods and procedures established by the Cochrane Collaboration. 
 
Findings: From our results, we found that 91 articles could be included. The literature search identified data from 9 countries (China, Japan, Malaysia, Mongolia, Pakistan, Russia Siberia region, South Korea, Thailand and Turkey), with 53,003 ticks form 6 genera, Amblyomma , Dermacentor , Haemaphysalis , Hyalomma , Ixodes and Rhipicephalus, inspected for infection with B. burgdorferi, the pooled B. burgdorferi prevalence was 11.1% (95% CI=8.3 -14.2%). Among the 9 countries, China has the most researches (56 studies) and Malaysia has the highest infection rate (46.2%). Most of the genus are Ixodes and Haemaphysalis, Ixodes has the highest infection rate (16.9%), among Ixodes species, I. persulcatus and I. granulatus are outstanding in quantity and B. burgdorferi carrying rate. There is obvious heterogeneity in this meta-analysis. We analyzed the heterogeneity from countries, genera, time points and detection methods. These heterogeneity indicators are statistically significant. 
 
Interpretation: This meta-analysis is the first attempt to explain the B. burgdorferi infection of Asian ticks. The infection rate of each country and the infection rate of different tick genus were analyzed, there are big differences between them. The currently published literature is mainly concentrated in East Asia with limited data. This article can provide a reference for a more comprehensive and in-depth study of Asian ticks infected by B. burgdorferi spirochetes. 
 
Funding: National Natural Science Foundation of China and Yunnan Province Department of Science and Technology-Kunming Medical University Joint Fundation. 
 
Declaration of Interest: We declare no competing interests.