Monsoon Health: The Illnesses That Arrive With the Rain
The monsoon reliably produces a surge of illness, and the pattern is predictable enough to prepare for. Most of it comes down to three routes: contaminated water, mosquitoes, and persistent dampness.
Water-borne illness
Flooding mixes sewage with drinking water, and the result is a seasonal rise in:
- Typhoid and paratyphoid, with gradual stepwise fever over days, headache, abdominal discomfort and often constipation
- Cholera, with profuse watery stools, in affected areas
- Hepatitis A and E, with jaundice, dark urine, pale stools and nausea. Hepatitis E is particularly dangerous in pregnancy, carrying a high mortality, and is strongly monsoon-associated
- Bacterial, viral and parasitic gastroenteritis
- Giardiasis and amoebiasis
Prevention: drink only boiled, filtered or sealed bottled water, including for brushing teeth during outbreaks. Avoid ice, cut fruit, juices, chutneys and salads from street vendors. Eat food freshly cooked and hot. Wash hands with soap. Store water covered. Clean overhead tanks before the season. Vaccination against typhoid and hepatitis A is worth considering.
Leptospirosis
The specifically monsoon disease, and the one most often missed.
Spread through water contaminated with the urine of rats and other animals, entering through broken skin or mucous membranes. Wading through flood water is the classic exposure, especially with a cut or abrasion on the foot.
Symptoms begin 2 days to 4 weeks after exposure: sudden high fever, severe headache, intense muscle pain particularly in the calves, red eyes without discharge, nausea, vomiting, abdominal pain. It can progress to Weil’s disease with jaundice, kidney failure, bleeding and lung haemorrhage.
Prevention: avoid walking through flood water. If unavoidable, wear rubber boots, cover any wound with waterproof dressing, and wash thoroughly with soap afterwards. Seek early medical attention for fever following flood exposure, because antibiotics work well when started early and poorly when started late. Preventive doxycycline is sometimes given to high-risk groups such as rescue workers.
Tell your doctor if you waded through water. This single piece of history changes the diagnosis.
Mosquito-borne disease
Dengue peaks during and after the monsoon. Aedes mosquitoes bite during the day and breed in clean stagnant water: coolers, flower pot trays, discarded tyres, construction sites, overhead tanks, bird baths and plastic containers on terraces.
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Chikungunya, with severe joint pain that can persist for months.
Malaria, spread by Anopheles, biting at night.
Japanese encephalitis in endemic rural and rice-growing areas, with a vaccine available.
Zika, less common but monitored.
Prevention: empty and scrub all water containers weekly, cover stored water, change cooler water and dry the tray, clear blocked gutters and terraces, use repellent containing DEET, picaridin or oil of lemon eucalyptus, wear full-sleeved clothing, use nets and screens, and use mosquito nets for day sleepers, since Aedes bites by day.
With fever in dengue season, use paracetamol and avoid NSAIDs until dengue is excluded.
Fungal and skin problems
Persistent humidity causes:
- Tinea, ringworm, in the groin, feet and body folds, which has become widespread and treatment-resistant in India, largely because of over-the-counter steroid-antifungal combination creams
- Athlete’s foot and toenail infection
- Candida in skin folds, particularly in people with diabetes
- Intertrigo in skin creases
- Folliculitis and boils
- Eczema flares
Prevention: dry thoroughly after bathing, especially between toes and in folds; change out of wet clothes and footwear promptly; wear cotton and open footwear; use antifungal dusting powder in prone areas; do not share towels, combs or footwear; and treat the whole household together, since reinfection within families is the main reason ringworm persists.
Never use steroid-containing combination creams on a fungal infection. They produce temporary relief and then a far worse, widespread, atypical infection.
Respiratory illness
Influenza, common colds, worsening asthma and allergic rhinitis from damp and mould, and increased indoor mould growth. Ventilate rooms, fix leaks and damp patches, and clean mould promptly.
Other monsoon hazards
- Snake bite, which rises sharply as snakes are displaced by flooding. Keep the limb still and below heart level, remove rings and tight items, immobilise, and get to a hospital with antivenom. Do not cut, suck, apply a tourniquet, or apply ice
- Electrocution from waterlogged wires and poles
- Injuries from slipping and from invisible open drains
- Eye infections: conjunctivitis spreads easily. Do not share towels; wash hands; avoid rubbing
- Water contamination of wounds, needing cleaning and a tetanus check
A sensible monsoon kit
ORS sachets, paracetamol, a thermometer, antiseptic, waterproof dressings, antifungal powder and cream, mosquito repellent, a working water filter, rubber boots and an umbrella.
When to see a doctor rather than wait
Fever lasting more than 48 hours, fever with severe muscle pain especially in the calves after flood exposure, fever with rash or bleeding, jaundice, severe headache with vomiting, breathlessness, reduced urine, persistent vomiting, or any fever in pregnancy.
This is general information. Monsoon fevers in India have several serious causes that look alike early on; a fever lasting more than two days deserves a doctor and a test, not guesswork.