Leptospirosis and its co-infections in India: prevalence, geographic distribution, and clinical implications.

BACKGROUND

Leptospirosis is a zoonotic disease prevalent in low and middle-income countries and tropical regions. It can be mimicked by endemic infectious diseases that present simultaneously, like dengue, malaria, melioidosis, or scrub typhus. However, there is a dearth of documented evidence about the frequency of coinfection, as well as related symptoms and mortality. The study aims to determine the frequency and geographical extent of coinfections in leptospirosis patients in India.

METHODOLOGY: We systematically searched databases, including Scopus, PubMed, Embase, and Web of Science, for articles published between January 2010 and August 2024 assessing coinfections in leptospirosis patients in India. The eligible articles were evaluated for full text data extraction using a standardized methodology.

RESULTS

Of 804 articles screened 39 studies were included; overall these reported on 1565 leptospirosis cases with 236 (15.1%) cases with coinfections. Of these, seven observational studies assessed coinfections in 1318 leptospirosis-positive cases, identifying 113 (8.6%) coinfections: most commonly dengue (79; 69.9%), followed by hepatitis E (15; 13.2%), typhoid (9; 7.9%), and malaria (9; 7.9%). The most coinfection cases were reported from New Delhi (29.6%), followed by Kerala (21.6%), Karnataka (14.4%), Uttar Pradesh (12.2%), and Tamil Nadu (5.5%). Common symptoms included fever, vomiting, icterus, headache, thrombocytopenia, and transaminitis. Cases with coinfection had poorer outcomes with increased mortality compared to cases with isolated infection.

CONCLUSION

In India, leptospirosis can present with co-infections such as dengue, hepatitis E, malaria, typhoid, and scrub typhus, complicating diagnosis due to overlapping clinical features. These coinfections are associated with unfavorable outcomes, including multi-organ dysfunction and increased mortality. Early diagnostic testing in febrile patients and timely, appropriate treatment are essential to improve patient outcomes.

TRIAL REGISTRATION: Clinical trial number: not applicable. Review protocol registration (Open Science Framework): DOI https://doi.org/10.17605/OSF.IO/AS9W5 .