Why in news?
Health officials in Karnataka reported that by the second week of November 2025, 2,042 cases of leptospirosis were recorded across the state, an increase from 1,879 cases in 2024 and 1,340 cases in 2023. Despite the rising numbers, authorities clarified that there was no outbreak; the increase reflects intensified surveillance, more testing and heavy monsoon rains that have boosted the rodent population.
Background
Leptospirosis is a zoonotic disease caused by spiral‑shaped bacteria of the genus Leptospira. The bacteria colonise the kidneys of animals—often rats, cattle, pigs and dogs—and are shed in their urine. Humans become infected when the bacteria enter through cuts on the skin or mucous membranes after contact with contaminated water, soil or food. Outbreaks are common in tropical regions following floods when stagnant water facilitates transmission.
Symptoms range from mild fever and muscle aches to severe illness marked by jaundice, kidney failure, meningitis or lung haemorrhage. Early treatment with antibiotics such as doxycycline or penicillin prevents complications.
Current situation in Karnataka
- Case numbers: The Integrated Disease Surveillance Programme recorded 2,042 cases statewide by mid‑November 2025. Udupi district had the highest tally (452 cases), followed by Dakshina Kannada (372), Shivamogga (288), Uttara Kannada (250) and Bengaluru (198).
- Test positivity: While testing increased by about 40 % compared with 2024 (from 10,068 to 14,034 samples), the positivity rate fell from 18 % to 13.8 %, suggesting the intensity of infection has declined even as more cases are detected.
- Reasons for spike: Heavy rain and waterlogging create ideal conditions for Leptospira to survive. Poorly managed garbage in urban areas allows rodents to thrive. In rural districts, farmers working in paddy fields and harvesting crops come into contact with contaminated water.
- Prevention and treatment: Public health messages urge people to avoid wading through stagnant water, wear boots and gloves during agricultural work, practise hand hygiene and control rodent populations. Early medical consultation is crucial; delayed treatment can lead to kidney and liver complications.
Broader context
Leptospirosis is endemic in many coastal and flood‑prone states of India, including Kerala, Tamil Nadu, Gujarat, Maharashtra and Karnataka. The National Centre for Disease Control monitors outbreaks and recommends prophylactic doxycycline for high‑risk groups during monsoon. Raising awareness among farmers, sewage workers and municipal staff remains key to prevention.
