MANILA CITY, METRO MANILA – The Department of Health (DoH) is advising the public to get rid of stagnant water in their surroundings and other possible mosquito breeding grounds to prevent the spread of dengue fever.

The DoH has raised the warning in light of its report that dengue cases in the country have already reached 40,648 from January to July, according to Health secretary Enrique Ona.

Of the total, the highest number of cases were reported from Central Mindanao (5,259 cases), Western Visayas (4,511), Eastern Visayas (4,086), CALABARZON (4,034), Southern Mindanao (3,875), Northern Mindanao (3,603), and the National Capital Region (3,452).

In Metro Manila, most of the cases were from Quezon City (754), Manila (606), Calookan (372), Navotas (227), and Valenzuela (221).

Based on DoH data, there were already 328 deaths from dengue recorded this year, up from 293 last year. Outbreaks were also detected in the municipality of Gasan in Marinduque and Barangay Banica, Lawaan in Roxas City, Capiz.

Dengue, a year-round disease, is more common during rainy days when there are more potential breeding sites for the female Aedes aegypti mosquitoes that can transmit the disease to humans.

Dr. Lyndon Lee Suy, program manager, emerging and re-emerging infectious diseases at the National Epidemiology Center of DOH, says it takes only 12 days for an egg to become an adult mosquito. A female Aedes aegypti mosquito is fertile throughout its life and can lay 60 to 100 eggs each time.

The egg has a thick shell or exochorion that allows it to survive for up to four months even under dry conditions.

“Have you ever wondered why clothes you hang to dry always have mosquitoes? The mosquitoes lay the eggs on the moist clothes if there is no stagnant water present because the eggs are protected by the shell to survive until the rainy season. The egg develops when exposed to rains and the mosquito population density rises,” Lee Suy says.

The DoH official also cites some important facts about dengue and reminders to prevent an outbreak:

Dengue-bringing mosquitoes bite during the day. The peak hours when the female Aedes aegypti mosquito bites humans and other hosts for food is the first two hours after sunrise and before sunset. Since this is the time that school kids travel to and from school, it is advised to lather on mosquito repellent lotions, wear protective clothing and avoid areas where mosquitoes breed.

Mosquitoes live on clean, stagnant water at 16-24 degree Celsius. Destroy all mosquito breeding sites like old tires, tin cans, dish drainers, under the kitchen sink, and kitchen drawers. Always clean roof gutters, cover pails of water and replace water in flower vases regularly to prevent eggs from morphing into adults. If there is stagnant water that cannot be covered for some reason, try to put salt to make it saline and kill the eggs or kiti-kiti (larvae) because one to 2.3 percent salt in the water kills the larvae.

How to know a dengue-carrying kiti-kiti. Like all mosquito larvae, the kiti-kiti of an Aedes aegypti mosquito is in the water and rests at an angle to the water surface or rests flat on the water surface. If you see this, drain the water immediately or to conserve water, add some salt on the container.

Don’t leave the doors open. To prevent mosquitoes from entering your house or car, close the doors or mosquito-proof your windows using nets. Don’t leave the doors open for a long time if you go outside especially during the day to prevent their entry to your house.

Mosquitoes are most likely to bite kids. If you wonder why most dengue cases involve children, this is because kids playing outside have warmer skin and have more movements, which attract mosquitoes. If you have ponds near your house, put fish there. Some fishes eat the larva of mosquitoes.

Visit the doctor if you have dengue symptoms. Symptoms of dengue such as fever, rash and headache are usually similar to that of flu, except that you have been bitten by a mosquito so be sure to note if you are bitten by a mosquito and if it was during day, see if the mosquitoes have white bands on its body characteristic of the Aedes aegypti.