Rare Zoonotic Infection Leptospira wolffii Detected in Human Samples for First Time in Northeast

Goalpara: In a concerning medical development, researchers have identified Leptospira wolffii, a rare zoonotic bacterium, in human clinical samples for the first time in Northeast India. The discovery was made during an investigation into a mysterious fever and jaundice outbreak that struck five villages in Assam’s Goalpara district earlier this year.

The outbreak, which occurred between February and March 2024, resulted in at least 11 deaths among 41 reported cases, many of which were complicated by co-infection with the Hepatitis A virus (HAV).

A joint team from the ICMR-Regional Medical Research Centre (RMRC), Dibrugarh, and partner institutions conducted the study, which has now been published in the International Journal of Medical Microbiology. Researchers found that 40% of patients tested positive for Leptospira-specific IgM antibodies, while 23.33% were HAV-positive. Alarmingly, 16.67% had both infections, worsening clinical outcomes.

Using serological tests and next-generation sequencing, scientists confirmed the presence of L. wolffii DNA in urine samples, marking the first recorded detection of this strain in humans in the region. The bacterium is suspected to have been introduced via cross-border transmission from neighboring Bangladesh, where the strain is known to circulate.

Leptospira wolffii, part of the P2 subclade of Leptospira, is an emerging pathogen that thrives in waterlogged and unsanitary environments, spreading through contaminated water and infected animal urine. Leptospirosis is a major global health concern, responsible for over 1 million infections and 60,000 deaths each year, mostly in tropical and subtropical regions.

Patients during the Goalpara outbreak presented symptoms including fever, jaundice, headache, nausea, and muscle pain. The severity of the illness, particularly in co-infected individuals, highlighted the need for better diagnostic protocols in such regions.

As part of immediate control measures, health officials advised villagers to consume safe drinking water and take weekly prophylactic doses of doxycycline (200 mg) to prevent further spread. The study has also recommended strengthened disease surveillance and sanitation infrastructure in vulnerable border districts.

This detection underscores the urgent need for public health preparedness against emerging zoonotic threats in the Northeast, especially as climate change and cross-border movement intensify risks of pathogen spillovers.