🦟 Dengue Prevention & Mosquito Bite Avoidance: Your Shield This Monsoon

Dengue is one of the most feared monsoon illnesses in India, and for good reason. It can cause severe, prolonged illness and life‑threatening complications. Yet, dengue is entirely preventable — if you understand how the mosquito that spreads it lives and breeds. Unlike malaria mosquitoes that prefer dirty drains, the Aedes aegypti mosquito that transmits dengue is a "domestic" mosquito: it breeds in clean, stagnant water around your own home. Dr. Ravi Sishir Reddy explains exactly where these mosquitoes hide, how to eliminate them, and how to protect yourself from their bites.

1. Know Your Enemy: The Aedes Mosquito

The Aedes aegypti mosquito is a daytime biter — most active during early morning (after sunrise) and late afternoon (before sunset). It has distinctive white markings on its legs and a lyre‑shaped pattern on its back. It cannot fly far; it stays within 200‑300 metres of where it hatched. That means the mosquitoes biting you most likely came from your own home or your immediate neighbour's. The female mosquito needs a blood meal to lay her eggs. After feeding, she lays eggs just above the water line in containers holding clean water. The eggs can survive for months in dry conditions and hatch when re‑exposed to water — this is why the mosquito population explodes at the start of the monsoon.

From egg to adult takes only 7‑10 days in warm weather. This rapid lifecycle means that even a small, overlooked container of water can produce a swarm of new mosquitoes within a week. The most effective way to prevent dengue is to eliminate these breeding sites.

2. Stop the Mosquito at Its Source: Eliminate Breeding Sites

This is the single most powerful step you can take. Dr. Reddy recommends a weekly routine — every Saturday or Sunday, take 10 minutes to inspect your home and surroundings:

• Flower pots, vases, and plant saucers: Empty and scrub them once a week. Change the water in flower vases every 2‑3 days and scrub the inside walls where eggs may be attached.
• Air coolers: These are major breeding sites. Drain and dry them completely once a week before refilling. Add a tablespoon of kerosene or a few drops of temephos larvicide to the water if you cannot empty it frequently.
• Water storage containers: Buckets, drums, and overhead tanks must be tightly covered with a lid or fine mesh. Mosquitoes can enter even a small gap.
• Old tyres, broken pots, and discarded containers: Remove them from your balcony, terrace, or yard. A discarded coconut shell or a plastic bottle cap with a teaspoon of water is enough for dozens of eggs.
• Drainage trays under refrigerators and air conditioners: Check and empty these hidden water collectors regularly.
• Gutters and sunshades: Clear leaves and debris that cause water to pool. Check for depressions in the roof or floor where water collects.
• Aquarium or ornamental fountains: Introduce fish that eat mosquito larvae, like guppies. Change the water regularly if fish are not present.
• Outdoor puddles: Fill or level them with sand or soil if possible. If not, a few drops of kerosene or a larvicide will prevent breeding.

Remember: the Aedes mosquito lays eggs just above the water line, not on the water surface. Scrubbing the inner walls of containers is essential — simply emptying the water is not enough to dislodge the eggs.

3. Protect Yourself from Mosquito Bites

Even with rigorous source reduction, you cannot control the entire neighbourhood. Personal protection adds a critical second layer of defence:

• Wear protective clothing: Long‑sleeved shirts, long trousers, and socks significantly reduce exposed skin. Light‑coloured clothing is less attractive to mosquitoes and makes it easier to spot them. Treating clothes with permethrin spray (available at travel clinics) provides additional protection that lasts through several washes.
• Apply mosquito repellent: Use a repellent containing DEET (20‑30%), picaridin (20%), or IR3535 on exposed skin. These are safe for adults, pregnant women, and children over 2 months (check the label for age‑specific concentrations). Apply sunscreen first, then repellent. Reapply repellent every 4‑6 hours, especially if you are sweating.
• Use physical barriers: Install fine‑mesh screens on windows and doors. If screens are not available, keep doors and windows closed during peak mosquito hours (early morning and late afternoon).
• Sleep under mosquito nets: Insecticide‑treated bed nets are highly effective. Even if you sleep during the day (for shift workers), a net is essential, as Aedes mosquitoes bite during daylight hours.
• Use mosquito coils, vaporisers, and sprays: Plug‑in electric vaporisers (liquid or mat) and mosquito coils can reduce indoor mosquito density. Use them in well‑ventilated rooms. An insecticide spray (pyrethroid) can be used in dark corners and behind curtains where mosquitoes rest during the heat of the day.

4. Community Efforts and Fogging

Dengue prevention works best when the entire community acts together. Dr. Reddy encourages patients to:

• Organise neighbourhood clean‑up drives before and during the monsoon to clear public areas of waste and stagnant water.
• Report abandoned plots, construction sites, or public areas with water accumulation to the municipal corporation.
• Understand the role of fogging: Ultra‑low volume (ULV) fogging with insecticides kills adult mosquitoes but does not kill larvae. It provides only temporary relief and is most useful during an active outbreak. Fogging alone cannot control dengue — source reduction is far more important.
• Community health workers can introduce larvivorous fish (guppies, Gambusia) in large water bodies and wells.

5. What About the Dengue Vaccine?

A dengue vaccine (Dengvaxia, CYD‑TDV) has been approved in some countries, but it is recommended only for individuals who have had a previous laboratory‑confirmed dengue infection. In people who have never had dengue, the vaccine may increase the risk of severe dengue if they are later infected. Therefore, the vaccine is not part of routine immunisation in India and is not a substitute for mosquito control. Research continues on more broadly effective dengue vaccines. For now, prevention through mosquito control and bite avoidance remains the only reliable strategy.

6. What to Do If You Suspect Dengue

If you develop a sudden high fever with severe body pain, headache behind the eyes, or a rash — especially during the monsoon — see a doctor immediately. Do not take ibuprofen, aspirin, or any NSAID, as these can increase the risk of bleeding. Paracetamol is the only safe antipyretic. Stay well‑hydrated and follow your doctor's advice regarding platelet monitoring and hospitalisation.

👉 Read more: Dengue Fever Symptoms & Platelet Count →