Scrub Typhus and its Risk Factors in Asian Countries: A Meta-analysis

Background: Scrub typhus is an infectious disease with potentially fatal consequences. It is caused by Orientia tsutsugamushi and transmitted to humans via the bites of infected larval mites (chiggers). Scrub typhus is one of the most neglected and severe diseases despite its easy treatment. Delay in diagnosis and treatment is not uncommon, resulting in a 10% fatality rate in cases of inappropriate treatment. The main aim of this study was to determine the prevalence of scrub typhus in Southeast Asia and the risk factors contributing to the disease in order to aid the development of effective control and prevention strategies. Methods: In this meta-analysis, the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) were used as a guideline. The systematic literature search was performed for the relevant titles, abstracts, and keywords in the journal databases of PubMed, EBSCOhost, Ovid, and Google Scholar in November 2018. The keywords and terms were derived from population, intervention, comparison, outcome analysis, and a total of 720 studies were retrieved accordingly. Only original research, published articles, and articles written in the English language were selected for this purpose. Screening of abstracts had shortlisted 36 studies and data extraction was conducted accordingly. However, only 9 studies were accepted after a review of the full texts. The other 27 articles were excluded due to ecological studies and different outcome measures. Results: Several factors in this meta-analysis were identified to have significant risk of having scrub typhus (P<0.05), including people who are involved in the agriculture sector (OR: 2.90, 95% CI: 2.33, 3.77), those having direct contact or being exposed to the vector habitat (OR: 2.17, 95% CI: 1.49, 3.16), and house yard conditions (OR: 3.02, 95% CI: 2.1, 4.33). Other factors were indoor house conditions (OR: 1.96, 95% CI: 1.45, 2.67), those having close contact with rodents or domestic animals (OR: 2.51, 95% CI: 1.67, 3.77), those working in paddy fields or vegetable farms (OR: 5.17, 95% CI: 3.15, 8.47), and bad occupational safety practices (OR: 1.71, 95% CI: 1.12, 2.62). Conclusions: The identified risk factors from this meta-analysis highlight the importance of public health intervention strategies for the prevention of scrub typhus among high-risk populations.