Declining Seroprevalence of Leptospirosis: A Three-Year Trend Analysis from a Tertiary Care Centre

Abstract

Introduction
Leptospirosis is an emerging zoonotic disease of global significance, often underdiagnosed due to nonspecific clinical features and overlap with other endemic febrile illnesses. North India, despite being vulnerable, has limited epidemiological data. This study aimed to determine the seroprevalence, clinical profile, complications, and co-infections of leptospirosis in patients presenting to a tertiary care centre.

Materials and Methods
A total of 500 clinically suspected patients attending All India Institute of Medical Sciences, New Delhi, between July 2022 and May 2024 were included. Blood samples were tested for anti-Leptospira-specific IgM antibodies using ELISA. Clinical details were assessed using Modified Faine’s criteria, and patients were screened for common co-infections including typhoid, malaria, dengue, and scrub typhus. Data were analyzed using STATA software, with p <0.05 considered significant.

Results
Of 500 suspected cases, 28 (5.6%) were seropositive, while none of the 25 healthy controls tested positive. Males (75%) were more affected than females, with a male-to-female ratio of 3:1. Adults formed the majority (92.9%), with mean age 39.8 years. Seasonal clustering was observed, peaking during the monsoon (50%). Fever was universal, followed by jaundice (46.4%), headache (42.9%), and myalgia (39.3%). Renal involvement was the most common complication (28.6%), followed by neurological (14.3%) and pulmonary (10.7%) manifestations. Co-infections were documented in 21.4% cases, most commonly typhoid.

Conclusion
Leptospirosis remains a clinically significant cause of febrile illness in North India, with seasonal predominance and potential for severe complications. Early diagnosis, heightened clinical suspicion, and preventive measures during monsoon are essential to reduce morbidity.