2. Dr Tushar Palve, medical superintendent of Cama and Albless Hospital, explains that leptospirosis is a water-borne bacterial infection and should not be confused with mosquito-borne diseases such as dengue and malaria. According to him-
Dengue and malaria are transmitted by mosquitoes. Typhoid is also a water-borne disease but enters the body through the mouth after consuming contaminated food or water. Leptospirosis enters through cuts or abrasions in the skin after contact with contaminated floodwater.
3. Thus, leptospirosis is a waterborne tropical zoonotic disease caused by pathogen Leptospira bacteria, which is spread through the urine of infected animals such as rodents, cattle, dogs and cats.
Why does leptospirosis spike during monsoon?
4. During the monsoon, contaminated urine and animal waste mix with floodwater and mud, allowing the bacteria to enter the body through even small cuts, abrasions or cracked skin. Because of its association with rodents and flooding, leptospirosis is commonly known as “rat fever” or “flood fever.”
5. According to Dr Mugdha Tapdiya, senior consultant, Fortis Flt Lt Rajan Dhall Hospital, Vasant Kunj, this disease usually affects animals and can spread to human beings if they are travelling through waterlogged areas. “Bacteria called leptospira which present in the excreta and urine of animals can infect human beings if they are exposed to it – they can be exposed if they are wading through contaminated water, if there is a cut in the skin which has been exposed to the bacteria.”
What are the symptoms of Leptospirosis?
6. Leptospirosis, which is endemic to most areas where dengue virus has been transmitted, needs a higher degree of suspicion to diagnose and may be mistaken for dengue in the early stages.
7. Symptoms can vary from mild illness to multiorgan involvement and is characterised with fever with chills, headache and body ache, rash, nausea-vomiting, congestion and redness in the eyes, with the more severe form showing features of Frank jaundice. However, if leptospirosis is left untreated, it can cause kidney damage and even prove to be fatal.
8. The first phase usually occurs five to 14 days after exposure to contaminated source with an abrupt onset of symptoms like pain in the muscles, eyes and headaches, followed by high fever and cold. The redness of the eyes appears first and other symptoms seem to increase gradually.
9. The patient may recover transiently but become ill again. If the second phase occurs, it is usually more severe with involvement of the liver or kidney failure and Meningitis. This phase can last from a few days to few weeks, or longer.
How is leptospirosis treated?
10. People exposed to flood water should seek medical advice within 24–72 hours. In high-risk situations, doctors may prescribe preventive antibiotics. The most commonly used prophylactic antibiotic is Doxycycline but it is avoided in pregnant women, children under eight years of age (unless the benefits outweigh the risks), people allergic to tetracycline antibiotics. For these groups, doctors may prescribe an alternative antibiotic.
11. For moderate to severe disease requiring hospitalisation, treatment may include intravenous antibiotics. Patients with severe disease may also require supportive care such as intravenous fluids, dialysis for kidney failure, oxygen or ventilator support, and intensive care monitoring. Vaccines, due to being specific for a particular strain of bacteria, do not offer widespread protection as there are over 200 strains of these bacteria.
What are the precautions to stay safe during the monsoon?
12. Doctors advise residents in flooded areas to pay particular attention to skin and foot care after exposure to floodwater. People who have no option but to walk through waterlogged areas should wear waterproof footwear or gumboots.
13. After returning home, feet should be washed thoroughly with soap and clean water and dried completely — especially between the toes. Any cuts or wounds should be cleaned with an antiseptic and covered with a clean dressing.
14. People with diabetes, poor circulation or weakened immunity should inspect their feet daily during the monsoon and seek medical attention if they develop redness, swelling, persistent pain or fever. Control rodent infestation around homes and workplaces, as rats are a major source of infection. Drink safe water and maintain good sanitation, particularly after floods.
BEYOND THE NUGGET: ICMR study for real time surveillance of zoonotic diseases
1. Researchers from various institutions across the country are collaborating on a new study to identify zoonotic spillover in environments where bird-human interactions are increasing. They said due to the limited data on zoonotic infections in the country, they are making an effort to develop a real-time surveillance model for detecting emerging pathogens that transmit diseases from animals to humans.
2. The Indian Council of Medical Research (ICMR) under Pradhan Mantri Ayushman Bharat Health Infrastructure Mission (PM-ABHIM)’s National One Health Mission has undertaken the study.
3. National Institute of Virology, Pune; Ela Foundation; National Institute of High Security Animal Diseases, Bhopal; Sir Thutob Namgyal Memorial Hospital, Gangtok; Pune forest department, Bombay Natural History Society, are also part of this initiative.
4. The researchers said they are using the ‘One Health’ approach, described by the World Health Organization (WHO) as an integrated, unifying approach that aims to sustainably balance and optimise the health of people, animals and ecosystems.
5. The study under PM-ABHIM assumes significance as India has limited data on zoonotic diseases such as Nipah infection, Ebola hemorrhagic fever, Zika infection, Covid, avian influenza, dengue, and chikungunya.
Post Read Questions
(1) With reference to Leptospirosis, consider the following statements:
1. It is a zoonotic disease caused by bacteria of the genus Leptospira.
2. It spreads primarily through the bite of infected mosquitoes.
3. Humans can become infected through cuts or abrasions in the skin after contact with contaminated floodwater.
Which of the statements given above is/are correct?
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
(2) Which one of the following statements best distinguishes leptospirosis from dengue?
(a) Leptospirosis is caused by a virus, whereas dengue is caused by bacteria.
(b) Leptospirosis is transmitted through contact with water contaminated by the urine of infected animals, whereas dengue is transmitted by mosquitoes.
(c) Leptospirosis spreads through respiratory droplets, whereas dengue spreads through direct contact with infected person.
(d) Both diseases are transmitted by mosquitoes breeding in stagnant water.
Answer key
1. (c), 2. (b)
(Sources: Wading through floodwater, Mumbai woman develops painful red bumps and fever: What is leptospirosis?, ICMR spearheads efforts to track diseases spreading from animals to humans with real-time surveillance, Leptospirosis: Know the causes, symptoms, and precautions to take for this monsoon disease)
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Beneath the floodwaters lies an unseen danger— disease-causing bacteria that spread from infected animals, turning the monsoon into a season of hidden health risks. (Image source: AI generated) 
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