Walking through floodwater may seem unavoidable during the monsoon. However, water contaminated by the urine of infected animals can carry Leptospira bacteria, which cause leptospirosis.
The first symptoms of leptospirosis commonly include sudden fever, headache, chills, tiredness and muscle pain, particularly in the calves or lower back. Nausea, vomiting, diarrhoea, abdominal pain and redness of the eyes may also occur. Symptoms can develop between 2 and 30 days after exposure, although they most commonly appear within 5 to 14 days.
Anyone who develops fever or severe body pain after walking through floodwater should tell the doctor about the exposure. Early medical evaluation is important because leptospirosis can initially resemble dengue, malaria, typhoid, flu and other monsoon-related illnesses.
What Is Leptospirosis?
Leptospirosis is a bacterial infection that affects both humans and animals. The bacteria are released through the urine of infected animals and can contaminate floodwater, wet soil, drains, puddles and freshwater sources.
Rodents are an important source of infection, although dogs, cattle, pigs, horses and several other mammals may also carry and release the bacteria. The bacteria can enter the human body through cuts or scratches, softened skin after prolonged water exposure, or through the eyes, nose and mouth.
India’s National Centre for Disease Control identifies leptospirosis as a significant public-health concern, particularly in coastal regions. Maharashtra is included in the national prevention and control programme, and pre-monsoon advisories are issued to improve detection, diagnosis and treatment.
Why Does Leptospirosis Risk Increase During the Monsoon?
Heavy rainfall and flooding can mix animal urine from streets, drains, farms and waste areas with standing water. A person may become exposed while:
- Walking through a waterlogged road
- Cleaning a flooded home, office or shop
- Working in drains, sewers or waste-management areas
- Handling wet soil or mud
- Working with animals
- Swimming or playing in contaminated freshwater
- Drinking or accidentally swallowing contaminated water
Leptospirosis outbreaks may occur after heavy rainfall or flooding, especially where poor drainage, sanitation problems or rodent activity increase contact with contaminated water.
What Are the First Symptoms of Leptospirosis After Walking Through Floodwater?
The early signs can look like a common viral fever. Initial leptospirosis symptoms may include:
- Sudden fever
- Chills
- Severe headache
- Muscle or body pain
- Pain in the calves or lower back
- Tiredness or weakness
- Nausea or vomiting
- Diarrhoea
- Abdominal pain
- Redness of the eyes
- Cough
- Occasionally, a skin rash
Calf-muscle pain and redness of the eyes may raise clinical suspicion, but these signs do not appear in every patient. Symptoms alone cannot confirm leptospirosis because several infections can produce a similar illness.
Quick Answer
Fever, headache and muscle pain developing within 2 to 30 days after contact with floodwater could be symptoms of leptospirosis. The risk is more concerning when the person had open cuts, remained in the water for a prolonged period or swallowed contaminated water.
How Long After Floodwater Exposure Do Symptoms Appear?
The incubation period is generally between 2 and 30 days. Most people who become ill develop symptoms approximately 5 to 14 days after exposure.
A person may initially feel unwell, improve briefly and then become sick again. This two-phase pattern can occur in leptospirosis, particularly when the illness progresses.
People exposed to floodwater should therefore watch for symptoms for around one month. Fever that develops several days after the exposure should not be dismissed simply because the person felt well immediately after walking through the water.
When Does Leptospirosis Become Serious?
Some infections remain mild, but untreated leptospirosis can affect the kidneys, liver, lungs, heart or the tissues surrounding the brain and spinal cord.
Seek urgent medical care when fever after floodwater exposure is accompanied by:
- Yellowing of the eyes or skin
- Reduced urine output
- Dark-coloured urine
- Difficulty breathing
- Chest pain
- Coughing up blood
- Persistent vomiting
- Severe weakness or fainting
- Confusion or unusual drowsiness
- Severe headache with neck stiffness
- Bleeding from the nose, gums or other areas
- Rapid worsening of symptoms
Severe leptospirosis can cause kidney failure, liver failure, respiratory failure, meningitis, internal bleeding or multiorgan dysfunction.
Is Every Fever After Floodwater Exposure Leptospirosis?
No. Fever during the monsoon may be caused by dengue, malaria, typhoid, influenza, COVID-19, gastroenteritis, other bacterial infections or viral illnesses.
However, floodwater exposure is an important clue. Inform the doctor about:
- The date of floodwater exposure
- How long you remained in the water
- Whether you had cuts or wounds
- Whether water entered your mouth, nose or eyes
- The date the fever began
- Other symptoms such as calf pain, red eyes, vomiting or reduced urination
This exposure history can help the doctor select appropriate examinations and tests.
Which Tests Are Used to Diagnose Leptospirosis?
A doctor may recommend leptospirosis testing based on symptoms, exposure history and the number of days since the illness began.
Diagnostic methods can include:
PCR Test
A PCR test looks for genetic material from the bacteria. Blood samples can be particularly useful during the early stage of the illness. Urine may become more useful later in the infection.
IgM Antibody Test
An IgM test checks whether the immune system has produced antibodies against the bacteria. Antibody tests may be more useful after the first several days of symptoms.
Microscopic Agglutination Test
The microscopic agglutination test, or MAT, is considered a reference serological test, although it may be performed mainly in specialised laboratories.
Supporting Blood and Urine Tests
The doctor may also request:
- Complete blood count
- Kidney-function tests
- Liver-function tests
- Electrolyte tests
- Urine examination
- Chest imaging when breathing symptoms are present
The timing of the test matters. A test performed too early may not always detect the infection, so the doctor may recommend a different test or a repeat sample when clinical suspicion remains high.
How Is Leptospirosis Treated?
Leptospirosis is treated with antibiotics prescribed by a qualified medical professional. Early treatment may reduce the severity and duration of the illness. Doctors may begin treatment when clinical suspicion is high rather than waiting for every laboratory result.
Patients with mild illness may be treated with oral medicines and close follow-up. Severe cases may require hospitalisation, intravenous antibiotics, fluids, oxygen support, kidney monitoring, dialysis or intensive care.
Do not start doxycycline or another antibiotic without medical advice. The appropriate medicine depends on the patient’s age, pregnancy status, allergies, kidney and liver health, symptoms and other medical conditions.
Should You Take Preventive Antibiotics After Walking Through Floodwater?
Preventive antibiotics are not automatically required after every exposure. Current CDC guidance states that there is limited evidence supporting routine post-exposure antibiotic use, and decisions should be made individually by a healthcare professional.
Seek medical advice if the exposure was extensive, if contaminated water entered a wound, or if you have a medical condition that may increase the risk of complications. Do not take leftover or non-prescribed antibiotics.
How Can Leptospirosis Be Prevented During the Monsoon?
The most effective preventive step is avoiding contact with potentially contaminated water and wet soil.
When exposure cannot be avoided:
- Wear waterproof boots and gloves.
- Cover cuts and scratches with waterproof dressings.
- Avoid touching your eyes, nose or mouth with unwashed hands.
- Do not swim, bathe or play in floodwater.
- Do not swallow floodwater or untreated freshwater.
- Wash exposed skin thoroughly with soap and clean water.
- Change wet clothing as soon as possible.
- Keep drinking water and food in covered containers.
- Dispose of waste properly to reduce rodent activity.
- Keep children away from waterlogged areas and open drains.
After flooding, drinking water should be boiled or appropriately treated when its safety is uncertain.
Leptospirosis Risk During the Navi Mumbai Monsoon
Residents of Nerul, Vashi, Sanpada, Seawoods, CBD Belapur, Kharghar, Koparkhairane, Ghansoli and nearby areas may encounter waterlogging during periods of intense monsoon rain.
After walking through accumulated water, wash your feet and legs thoroughly, clean any wound and monitor your health for the next 30 days. Fever, calf pain, red eyes, vomiting, jaundice, reduced urination or breathing difficulty should be medically evaluated without delay.
When Should You Visit a Hospital?
Consult a doctor promptly when:
- Fever develops after floodwater exposure
- Fever lasts for more than one or two days
- Body pain is unusually severe
- The calves or lower back are very painful
- The eyes appear red
- Vomiting prevents normal fluid intake
- Urine output decreases
- The skin or eyes become yellow
- The patient has diabetes, kidney disease, liver disease or reduced immunity
- A child, older adult or pregnant woman develops symptoms after exposure
Go to the emergency department immediately for breathlessness, confusion, fainting, bleeding, severe chest pain, coughing up blood, very low urine output or rapidly worsening symptoms.
Frequently Asked Questions
Can leptospirosis spread through floodwater?
Yes. Floodwater can become contaminated with urine from infected animals. The bacteria may enter through cuts, softened skin or the eyes, nose and mouth.
How quickly do leptospirosis symptoms appear?
Symptoms can appear between 2 and 30 days after exposure, with most illnesses beginning within approximately 5 to 14 days.
Is calf pain a symptom of leptospirosis?
Muscle pain, particularly in the calves and lower back, is a recognised symptom. However, calf pain alone does not confirm the infection.
Which leptospirosis test should I take?
The appropriate test depends on how many days have passed since symptoms began. A doctor may recommend PCR, IgM antibody testing, MAT or supporting blood and urine investigations.
Is leptospirosis curable?
Leptospirosis can be treated with antibiotics. Early diagnosis and medical treatment can help reduce the severity and duration of the disease. Severe cases may require hospitalisation and organ-support treatment.
Can leptospirosis spread from one person to another?
Person-to-person transmission is considered rare. Most infections occur through contact with water, soil, food or surfaces contaminated by infected animal urine.
Do Not Ignore Fever After Floodwater Exposure
Leptospirosis may begin like an ordinary viral fever, but it can become serious when diagnosis and treatment are delayed. The combination of recent floodwater exposure, fever, headache, calf pain, red eyes, vomiting or reduced urine output should be reported to a doctor.
For fever or illness after floodwater exposure, consult the Internal Medicine or Emergency team at Terna Speciality Hospital & Research Centre, Navi Mumbai. Seek emergency care immediately for breathing difficulty, jaundice, confusion, bleeding or reduced urine output.
Medical Disclaimer: This article is intended for general health awareness and does not replace consultation, examination, diagnosis or treatment by a qualified healthcare professional.