Mapping Scrub Typhus Across Multiple Hosts in India.

Abstract

Scrub typhus is a significant public health concern in India. Despite numerous studies on its prevalence across hosts and vectors, country-specific data remain unavailable. This systematic review and meta-analysis provide comprehensive insights into the prevalence of scrub typhus across humans, animal hosts, and vectors to aid disease control programs. The PECOS framework was used to identify eligible studies. A systematic search across six databases (PubMed, Scopus, Web of Science, Google Scholar, Krishikosh, and Shodhganga) was conducted in March 2024. Data were classified by diagnostics and disease distribution across hosts and vectors for narrative synthesis. Study bias was assessed using a prevalence study checklist. A random- or common-effects meta-analysis model estimated overall and subgroup pooled prevalence across population types and diagnostic tests, with heterogeneity measured by the I² index. A total of 83 eligible studies published between 2003 and 2024 covered different regions, hosts, and vectors. The pooled prevalence (95% CI) of scrub typhus was 20% (11-34%) in 17,826 hospitalized AES cases, 19% (14-25%) in 28,617 hospitalized AUFI cases, and 13% (5-27%) in 14,828 community individuals. The animal level pooled prevalence in 1782 rodents/shrews was 6% (2-13%) with 6% (1-27%) of seroprevalence and 8% (3-19%) of molecular prevalence. The pooled prevalence in 1037 ectoparasite vector pools was 5% (1-17%). The meta-regression analysis suggested that geographical region, publication year, and sampling strategy were the prime moderators in community individuals, whereas season was the moderator in AUFI cases. Scrub typhus distribution was influenced by season, with regional differences in circulating strains as well as host and vector species predilection. This study highlights a high burden of disease in multiple hosts and vectors, along with hospitalized cases, suggesting differential diagnosis. A One Health approach is crucial for disease control, focusing on vector control and rodent management.