🐀 Leptospirosis: Symptoms & Prevention During the Monsoon

Every monsoon, as streets flood and water levels rise, a hidden danger lurks in the murky water: leptospirosis. This bacterial infection spreads through water contaminated with the urine of infected animals — particularly rats. Anyone who wades through floodwater, works in wet fields, or handles animals is at risk. The early symptoms look deceptively like a viral fever, but without prompt antibiotic treatment, leptospirosis can rapidly progress to cause liver damage, kidney failure, and severe bleeding. Dr. Ravi Sishir Reddy explains how to recognise leptospirosis, why early treatment is critical, and how to protect yourself during the monsoon.

1. What Is Leptospirosis?

Leptospirosis is a bacterial infection caused by spirochetes of the genus Leptospira. It is a zoonotic disease — meaning it spreads from animals to humans. The bacteria live in the kidneys of infected animals, particularly rats and rodents, but also cattle, pigs, dogs, and other mammals. These animals excrete the bacteria in their urine. Humans become infected when the bacteria enter the body through:

• Broken skin: Cuts, scratches, or abrasions that come into contact with contaminated water or soil.
• Mucous membranes: The eyes, nose, or mouth splashed with contaminated water.
• Intact skin submerged in water for prolonged periods — the skin softens, allowing bacterial entry.

The disease has a strong seasonal pattern, with a sharp increase in cases during and immediately after the monsoon. In urban areas like Hyderabad, leptospirosis is typically seen in people who have walked through flooded streets or live in areas with poor sanitation and a high rodent population. In rural areas, farmers, fishermen, and sugarcane workers are at highest risk.

2. The Two Faces of Leptospirosis: Mild and Severe

Leptospirosis presents as a biphasic illness — two distinct phases separated by a brief period of apparent improvement. Not everyone progresses to the severe phase, but recognising the pattern is essential.

Phase 1 – The Septicemic Phase (First 3‑7 Days)

The bacteria are circulating in the blood. Symptoms resemble a sudden, severe flu:

• Sudden high fever (often above 102°F / 39°C) with chills and rigors.
• Severe headache, often accompanied by pain behind the eyes (retro‑orbital pain).
• Intense muscle pain (myalgia) — especially in the calves and lower back, which is a characteristic feature. The calf muscles may be exquisitely tender to touch.
• Red eyes (conjunctival suffusion): The eyes appear bloodshot, but there is no discharge or itching — this is a very helpful diagnostic clue in the first few days.
• Nausea, vomiting, and abdominal pain.
• A transient skin rash may appear.

After 3‑7 days, the fever may drop temporarily, and the patient may seem to improve.

Phase 2 – The Immune (Leptospiruric) Phase (Days 5‑14)

In about 5‑15% of cases, the disease returns with a vengeance as the immune system responds to the bacteria. This second phase is far more dangerous and is called Weil's disease when it involves jaundice and kidney failure:

• Jaundice: The skin and whites of the eyes turn yellow due to liver inflammation.
• Acute kidney injury: Urine output drops dramatically; blood tests show rapidly rising creatinine and urea.
• Bleeding tendency: The gums, nose, and skin may bleed. This is due to thrombocytopenia (low platelets) and impaired clotting factors.
• Pulmonary haemorrhage: Coughing up blood and severe breathing difficulty due to bleeding into the lungs. This is the most common cause of death in severe leptospirosis.
• Meningitis: Inflammation of the brain coverings, causing severe headache, stiff neck, and sensitivity to light.
• Myocarditis: Inflammation of the heart muscle, causing palpitations, chest pain, and in severe cases, heart failure.

The transition from Phase 1 to Phase 2 can happen rapidly, often catching patients and doctors off guard. This is why Dr. Reddy emphasises that any fever following contact with floodwater should be taken seriously and evaluated early.

3. How Is Leptospirosis Diagnosed?

Because the early symptoms overlap with dengue, malaria, typhoid, and influenza, laboratory confirmation is crucial. The most useful tests are:

• Serology (IgM ELISA or MAT): The most common diagnostic method. The IgM ELISA detects antibodies against Leptospira and becomes positive about 5‑7 days after symptom onset. The Microscopic Agglutination Test (MAT) is the gold standard but is available only in reference laboratories and is more time‑consuming.
• PCR (Polymerase Chain Reaction): Can detect leptospiral DNA in the blood or urine during the first week of illness, before antibodies develop. Useful for early diagnosis but not widely available in all settings.
• Blood tests: A complete blood count often shows a normal or elevated white blood cell count (unlike dengue, which usually shows leukopenia), low platelets, and elevated liver enzymes (ALT, AST, bilirubin) and creatinine. Creatine kinase (CK) is often markedly elevated due to muscle involvement.

In practice, a doctor will often start treatment empirically based on a strong clinical suspicion — especially if the patient has a compatible history (floodwater exposure) and characteristic findings (calf tenderness, red eyes) — while waiting for test results. Delaying treatment until confirmation can be dangerous.

4. Treatment: Early Antibiotics Save Lives

Leptospirosis is a bacterial infection and responds well to antibiotics if started early. The sooner treatment begins, the lower the risk of progressing to the severe phase. Dr. Reddy outlines the standard treatment:

• Mild disease (outpatient): Oral doxycycline (100 mg twice daily for 7 days) is the drug of choice. Alternatively, amoxicillin or azithromycin can be used in patients who cannot take doxycycline (e.g., pregnant women, young children). Treatment started within the first few days of fever dramatically reduces the risk of severe complications.
• Severe disease (inpatient): Hospitalised patients with jaundice, kidney failure, or pulmonary involvement require intravenous penicillin G, ceftriaxone, or cefotaxime. Intravenous antibiotics are continued for at least 7 days. Supportive care — including intravenous fluids, dialysis for kidney failure, platelet transfusions if needed, and mechanical ventilation for pulmonary haemorrhage — is provided in an intensive care unit.

Dr. Reddy notes that a Jarisch‑Herxheimer reaction — a temporary worsening of fever, chills, and hypotension occurring a few hours after the first dose of antibiotics due to the release of bacterial toxins — can happen with penicillin therapy. It is managed conservatively and does not mean the treatment should be stopped.

5. How to Prevent Leptospirosis During the Monsoon

Prevention hinges on avoiding contact with contaminated water and controlling the rodent population. Dr. Reddy's practical advice:

• Avoid wading through floodwater if at all possible. If you must, wear knee‑high gumboots or waterproof boots that completely cover the feet and lower legs. Avoid open sandals or going barefoot.
• If your skin comes into contact with floodwater, wash the area thoroughly with soap and clean water immediately.
• Cover any cuts, scrapes, or wounds with a waterproof bandage before any potential exposure.
• Keep your home rodent‑free: Seal holes and gaps in walls, doors, and windows. Store food in rodent‑proof containers. Dispose of garbage properly in closed bins. Keep the kitchen and surrounding areas clean.
• Avoid swimming or bathing in lakes, ponds, or canals that may be contaminated with animal urine, especially after heavy rains.
• For high‑risk occupations (farmers, sewage workers, veterinarians, construction workers): Protective clothing, gloves, and boots should be worn. Prophylactic doxycycline (200 mg once weekly) may be prescribed by a doctor during the peak monsoon season in highly endemic areas.
• For pets: Vaccinate dogs against leptospirosis. The canine vaccine does not cover all serovars but reduces the risk. Do not allow pets to wade through floodwater.

6. When to Seek Medical Attention Immediately

Because leptospirosis can progress rapidly from a mild flu‑like illness to a life‑threatening multi‑organ disease, Dr. Reddy advises seeking medical attention if you have:

• Fever (especially above 101°F / 38.3°C) that starts a few days after contact with floodwater, soil, or animals.
• Severe muscle pain, especially in the calves, that is out of proportion to other symptoms.
• Red, bloodshot eyes with no discharge.
• Dark urine or a significant decrease in urine output.
• Yellowing of the skin or eyes (jaundice).
• Coughing up blood or severe difficulty breathing.
• Any abnormal bleeding — from the gums, nose, or in the urine or stool.

Do not dismiss the fever as "just a viral." Every hour counts — the difference between an outpatient course of doxycycline and a prolonged stay in the intensive care unit can be as little as 24‑48 hours of delay in starting antibiotics.