A Story from the Field: The Water Left, and the Mosquitoes Arrived

Auntie Boonmee lives in a two-story wooden house raised on stilts beside the Khwae Noi River in Wat Bot District, Phitsanulok. During the 2026 floods, water poured in under the house, across the yard and into the vegetable garden behind it, and stayed for almost two weeks. When it finally drained away, her children and grandchildren came to help. They shoveled out the mud, scrubbed the floors and sorted through everything that had been damaged. Everyone felt relieved. The hardest part, they thought, was over.

A few days later, the mosquitoes came. There were far more than usual. In the evenings, the family could no longer sit and eat in the open space under the house, which had always been the coolest and most pleasant spot. Her eight-year-old granddaughter, who had come to help, was covered in bites on her arms and legs. Inside the house, cockroaches and flies swarmed over the wet rubbish the flood had carried in. The space under the house still smelled of mud and of timber that had soaked for too long.

Not long after, the granddaughter developed a high fever that would not come down for two days, along with a headache and aching muscles. Auntie Boonmee took her to the district hospital. The doctor examined her and asked the family to monitor her closely because dengue fever was suspected. Fortunately, they had come early, and her condition was managed under medical care. "During the flood, I was afraid of the water," Auntie Boonmee said. "Once the water went down, I was afraid of the mosquitoes."

This can happen in many parts of Wat Bot, including Tha Ngam, Thothae, Ban Yang, Hin Lat and Khan Chong subdistricts, as well as other riverside communities across Phitsanulok. This article explains why mosquitoes increase after floodwater recedes, what every household can do right away, and how a complete home recovery approach can help families get back to normal safely.

The health information in this article is general knowledge. If anyone has a high fever, headache, body aches or any unusual symptoms, see a doctor immediately and follow the advice of the Department of Disease Control and your local hospital.

Why Mosquitoes and Insects Increase After a Flood

When floodwater recedes, it does not disappear completely. It stays behind in containers, hollows in the ground, old tires, flower pots, water jars, buckets and the rubbish the current carried in. Each of these becomes an ideal mosquito breeding site. The Aedes mosquito, which carries dengue fever, prefers to lay its eggs in still, fairly clear water in containers around the home. Culex mosquitoes, the common nuisance biters, prefer dirty standing water. Both species can multiply rapidly in the weeks after a flood.

The timing matters. Mosquito eggs can hatch into larvae within days, and larvae can become biting adults in about a week to ten days in warm weather. This means that a single bucket of rainwater left in the yard after the flood can produce a new generation of mosquitoes before the family has even finished cleaning the house.

Mosquitoes are not the only problem. Flies and cockroaches also increase because there is food waste, wet rubbish and sometimes dead animals left behind by the water. These insects can carry germs onto food and surfaces inside the home, especially in kitchens that were flooded and have not yet been properly disinfected.

How this affects families

• Dengue fever: caused by a virus carried by the Aedes mosquito. It often brings a sudden, persistent high fever, headache and muscle aches. Children and people with underlying health conditions need close care. Do not take certain types of painkillers or fever medicine on your own; always consult a doctor or pharmacist first.
• Diseases from water and contamination: diarrhea from food that flies have landed on, skin inflammation, and leptospirosis from wading through mud without rubber boots.
• Mold and musty odors: wooden houses and the space under raised houses that sat in water for a long time hold moisture, which allows mold to grow and can trigger allergies and asthma.
• Time and money: when family members fall ill, they have to miss work and school, and medical costs add up at exactly the moment the household is trying to recover.

Methods That Usually Fall Short When Used Alone

Burning mosquito coils or spraying insecticide indoors. These keep mosquitoes away from one spot for a short time. But if breeding sites around the house remain, a new generation of mosquitoes is born every day, and the problem never really ends.

Mosquito spraying without removing standing water. Spraying can reduce adult mosquitoes for a period, but larvae in containers keep developing. Spraying must always go hand in hand with removing breeding sites.

Washing the house with bleach only. Bleach helps on some hard surfaces, but it does not deal with musty odors or mold spores in the air, and the smell of chlorine in a closed, damp wooden house can irritate the eyes and lungs.

Letting the space under the house dry by itself. Timber and soil under a raised house can stay damp for a long time and become a hiding place for mosquitoes and other insects.

The most effective approach combines what families can do themselves every week with professional services that deal with the parts that are hard to reach or hard to treat properly.

What You Can Do Right Now: Remove Mosquito Breeding Sites Around the Home

1. Tip out or empty water from every kind of container, such as basins, buckets, cans, flower pots and old tires.
2. Cover water jars and storage tanks tightly, or cover their openings with cloth or mosquito mesh.
3. Change the water in vases and cabinet-leg ant traps every week, or add salt or sand as recommended by public health authorities.
4. Collect rubbish carried in by the flood, especially bottles, plastic bags and foam boxes that may hold water.
5. Fill in or drain puddles around the house and under it.
6. Check rain gutters and drains so they are not blocked with leaves and holding water.
7. Protect yourself by wearing long sleeves and long trousers, using mosquito repellent and sleeping under a mosquito net, especially children and older family members.

These steps follow the general principles promoted by public health agencies. Every household can do them, and they should be repeated at least once a week until the area is fully dry.

A Complete Home Recovery Approach from World Health Disinfection

For homes that went through heavy flooding, WHD can combine its services into a package based on the conditions on site, so that mosquitoes, germs, mold and odors are all handled in one visit. The team will assess the home and propose the details after the site survey.

1. Mosquito spraying around the home and under the house

The mosquito spraying service helps reduce adult mosquitoes around the home, under the house, in shrubs and in the shady spots where mosquitoes rest. It should always be combined with removing breeding sites. During spraying, people and pets should stay away from the area, food should be covered or put away, and everyone should follow the team's advice on when it is safe to return.

2. Disinfection fogging inside the home

The disinfection service uses Chemgene HLD4H disinfectant applied by ULV fogging machines. The fine mist helps deal with germs left behind by flood stains and in the places where flies and cockroaches have been, including floors, walls, kitchens and shared touch points such as door handles, light switches and tables.

3. Ozone treatment for musty odors and mold

The ozone treatment service helps deal with airborne mold spores and breaks down the musty smell of timber that sat in water. It suits wooden houses and closed rooms particularly well, because ozone gas reaches into the gaps between boards, inside wardrobes and behind furniture. No people, pets or plants may be in the room during treatment. Electronics that are sensitive to ozone are moved out or covered, the dose is controlled, and the room must be well ventilated before anyone goes back inside. After ventilation, the ozone breaks down into oxygen.

Step-by-step process

1. Site survey: check mosquito breeding sites, moldy areas, moisture levels and electrical appliances.
2. Advice on mud removal and standing water: identify which areas should be cleared before the service day.
3. Disinfection fogging inside the home.
4. Controlled-dose ozone treatment, one room or one zone at a time.
5. Mosquito spraying around the home at a suitable time of day.
6. Ventilation and re-check: with advice on ongoing care.

Risk Spots in Raised Wooden Riverside Homes That Are Often Overlooked

Many homes in Wat Bot are wooden houses on stilts or half-concrete, half-timber houses along the Khwae Noi River. They have more hidden corners where water lingers and mosquitoes hide than a typical concrete house. Before you call the team, walk around and check these spots yourself:

• Under wooden daybeds and stacks of timber beneath the house, where the ground is still damp and shaded. Mosquitoes rest there during the day.
• Old boats, lotus basins and large glazed water jars kept beside the house, which often collect rainwater and larvae without anyone noticing.
• Joints between floorboards and wall panels, where mud has worked its way in. These become sources of mold and musty odors that rise into the bedrooms upstairs.
• Chicken coops, duck pens and animal water troughs. Change the water daily and wash the containers so they do not become breeding sites.
• Mattresses, pillows and mosquito nets that got wet. If they still smell musty or show black spots, wash and dry them in strong sun or replace them. A mosquito net is a child's most important line of defense while mosquitoes are everywhere.

Warning Signs That Mean You Should See a Doctor Quickly

In the weeks after the water recedes, anyone in the household who has a high fever for more than two days should see a doctor without waiting for symptoms to get worse. Go to the hospital immediately if you notice any of the following, especially around the time the fever starts to come down:

• Drowsiness, extreme weakness, or being unable to eat or drink
• Severe stomach pain or frequent vomiting
• Unusual bleeding, such as nosebleeds, bleeding gums or red spots on the skin
• Cold hands and feet, a cold body, or passing much less urine than usual
• Fever, severe calf pain or red eyes after wading through floodwater, which may be signs of leptospirosis

While someone has a fever, have them rest under a mosquito net so that mosquitoes cannot bite them and spread the virus to others in the house. Follow updates from your subdistrict health promoting hospital or the village health volunteers in your community.

A Four-Week Home Care Plan After the Water Recedes

1. Week 1: Remove mud, throw away wet rubbish, turn over every container and book a site survey.
2. Week 2: Disinfection fogging inside the home, ozone treatment for bedrooms and musty rooms, and mosquito spraying around the property.
3. Week 3: Walk around and check for standing water again, change the water in containers and look out for mold spots that may return.
4. Week 4: Review with the team whether a follow-up mosquito spray is needed, and move belongings back once the house is completely dry.

Following a simple plan like this keeps the whole family focused and makes sure that nothing important is forgotten during a busy and stressful time.

It also helps to share the plan with neighbors. Mosquitoes do not respect fences, and a single neglected yard next door can keep producing new mosquitoes for the whole lane. When several households along the same stretch of the Khwae Noi River clear breeding sites on the same day each week, and coordinate spraying around their homes, the results last much longer for everyone. Village leaders and health volunteers are often happy to help organize a shared clean-up day.

Common Myths About Mosquitoes After a Flood

"The floodwater was dirty, so dengue mosquitoes cannot breed in it." The Aedes mosquito prefers fairly clear water, and that is exactly what collects in jars, pots, tires and rubbish after the muddy water drains away and the rain refills them. The risk often rises after the flood, not during it.

"We sprayed once, so the problem is solved." Spraying reduces the adult mosquitoes that are flying at the time. Eggs and larvae hidden in containers are not affected, so a new generation can appear within one or two weeks unless breeding sites are removed.

"Mosquitoes only bite at night." The Aedes mosquito is mainly active during the day, particularly in the morning and late afternoon. Children playing outside or napping without a net during the day still need protection.

"Only houses with dirty yards have mosquitoes." A single forgotten flower pot saucer or a water jar with a loose lid is enough. Even very tidy homes need a weekly walk-around to check for standing water.

"Ozone treatment will keep mosquitoes away." Ozone is excellent for odors, mold spores and airborne germs inside closed rooms, but it is not a mosquito control method. Each tool has its own job, which is why WHD combines them into one recovery plan.

Protecting the Most Vulnerable Family Members

Children, older people, pregnant women and people with chronic conditions such as diabetes, heart disease or kidney disease need extra care while mosquitoes are everywhere and the house is still recovering. Let them sleep in the room that has already been cleaned and treated, under a mosquito net, and keep them away from the dusty, muddy work of clearing the space under the house. Dress young children in light, long-sleeved clothing and apply repellent suitable for their age. If an older relative already has allergies or asthma, a musty, moldy bedroom can make breathing harder, so that room should be one of the first to receive disinfection fogging and ozone treatment. Keep a simple note of anyone in the family who develops a fever, with the date it started, so you can give the doctor clear information if you need to go to the hospital.

10 Reasons Homes in Wat Bot Choose WHD

1. Mosquitoes, germs, mold and odors are all handled in a single appointment.
2. A mosquito spraying service for the area around the house and underneath it.
3. Disinfection fogging with ULV fine mist that reaches into corners.
4. The team uses Chemgene HLD4H disinfectant as part of its everyday work.
5. Ozone treatment helps remove the musty smell of waterlogged timber.
6. Practical advice on removing breeding sites that families can keep doing themselves.
7. Controlled ozone dosing that protects electrical appliances.
8. Clear guidance on when to leave the area and how long to ventilate.
9. Understanding of raised wooden riverside homes. Read more about ozone disinfection for homes.
10. Easy to contact: call 065-556-6294 or LINE @whd268 to check service areas in Phitsanulok.

Before and After

Customer Voice (Example Scenario)

"After my granddaughter got sick, my son contacted the team to come and look at the house. They walked us around and pointed out every place where water was collecting, even inside old tires and the pots behind the house. Then they sprayed for mosquitoes, fogged the inside of the house and ran ozone treatment in the bedrooms. Now we can sit and eat under the house in the evening again, and the musty smell inside is much lighter."

— Auntie Boonmee, a wooden riverside house in Wat Bot District (example scenario)

Frequently Asked Questions

Q: Is one round of mosquito spraying enough?
A: Spraying reduces adult mosquitoes for a period, but if standing water remains, a new generation will appear. Breeding sites must be removed continuously, and a follow-up spray may be scheduled on the team's advice.

Q: What should we do during mosquito spraying?
A: Keep people and pets away from the area, cover or put away food, drinking water and containers, and return only when the team says it is time.

Q: Does ozone treatment get rid of mosquitoes?
A: Ozone treatment is mainly designed to deal with airborne germs, mold spores and odors. It is not designed to kill mosquitoes directly, so mosquito spraying and breeding-site removal should be used alongside it.

Q: What should we do if someone has a high fever after the flood?
A: See a doctor quickly, especially for children and older people, and tell the doctor that your home is in a flooded area. Do not buy certain types of painkillers or fever medicine on your own without asking a doctor or pharmacist.

Q: How should we prepare a raised wooden house before the service day?
A: Clear the mud from under the house, collect rubbish, turn containers upside down, move pets, potted plants and food out of the area, and unplug electrical appliances in rooms that will receive ozone treatment.

Q: Which parts of Phitsanulok do you cover?
A: Ask about service areas and available dates via LINE @whd268 or call 065-556-6294.

Protect Your Family from Mosquitoes and Germs After the Flood

Book a site survey for your home in Wat Bot and nearby areas.

See Mosquito Spraying Service, Click Here

See Disinfection Service, Click Here

Book Ozone Treatment, Click Here

Call 065-556-6294 · LINE @whd268 · Email worldhealthdisinfection@gmail.com

Related Links

• Mosquito spraying service
• Ozone disinfection for homes
• Chemgene HLD4H disinfectant spray 750ml
• All articles

Health references: Department of Disease Control · World Health Organization (WHO): Floods