The start of the rainy season also marks the start of the mosquito season, and Phuket's Provincial Health Office (PPHO) has launched a new public education campaign to head off the spread of dengue fever. According to a PPHO official who asked not to be named, statistics show that Phuket has had 83 cases of dengue fever during the first four months of 2008. Currently, the official added, Phuket has only "a few" active cases.
"In 2007 we had three people die from dengue fever," the official said. "They were 15, 18 and 21 years old. This year we have patients aged around 10-14 years old. Most patients are children and teenagers because that's the age when they get fevers, and parents think it's not a big matter. So they buy some drugs at the nearby pharmacy that can cause bleeding in the internal organs. When you take certain drugs with dengue fever, it can cause bleeding that's very dangerous or quickly fatal. If you get a fever in the rainy season, you should have a blood test to make sure you don't have dengue fever."
Dengue fever is manifested by a sudden onset of fever, with severe headache, muscle and joint pains and rashes. (The severe pain from dengue fever has earned the disease the nicknames "break-bone fever" and "bonecrusher disease".) The dengue rash is characteristically bright red from localized hemorrhages on the skin or mucous membranes. They usually appear first on the lower limbs and the chest. In some patients, they spread to cover most of the body. There may also be gastritis with some combination of associated abdominal pain, nausea, vomiting or diarrhea.
With dengue fever, it is very important to avoid aspirin and non-steroidal anti-inflammatory drugs. These may aggravate the bleeding tendency associated with some dengue fever infections. Patients should receive paracetamol preparations to deal with symptoms if dengue is suspected.
The PPHO's education campaign involves sending out the message about dengue fever prevention through public health clinics, doctors and directly to high-risk communities. The PPHO has posted a new poster outlining how mosquitoes spread the virus and has made colour brochures on dengue fever available for distribution.
On Phuket, the official said, the highest-risk areas are Muang, Thalang and Kathu. The culprit is the aedes aegypti mosquito, commonly known as the yellow fever mosquito. Places where they can breed most effectively have the highest risk. The people who get dengue fever typically live in crowded and untidy house with areas of standing water outside where mosquitoes can breed. Thais are most often affected. Tourists staying in hotels rarely contract the disease, the official said.
"The common house mosquito is the carrier of dengue fever," the official said. "Common house mosquitos lay eggs in only clear water. Most people think the common house mosquito lays eggs in dirty water, like in the water-distribution canal or flood channels. Beware in your house of jars or cups -- dump the water out and invert the container."
The PPHO's materials explain that dengue fever is one of two acute febrile diseases caused by four closely related virus serotypes of the genus flavivirus and family flaviviridae. The geographical spread is similar to malaria, but unlike malaria, dengue fever is often found in urban areas of developed tropical nations, like Phuket. The mosquitoes that spread the disease are most prevalent during the May to September rainy season, and they feed during the day.
The easy way to protect the mosquito consists of the use of mosquito nets, repellents containing NNDB or DEET, covering exposed skin, use of DEET-impregnated bed nets, and avoiding endemic areas, the PPHO materials explain. Public spraying of insecticides is the most important way to reduce the risk of dengue fever, using larvicides such as Abate on standing water. Initiatives to eradicate pools of standing water (such as in flowerpots) have proven useful in controlling mosquito-borne diseases.
"Actually if we continually spray for the mosquitoes, it makes them resistant to pesticides. So we spray when know a certain community has a dengue fever patient and a doctor has gone out to the community to check the area," the official said. "Dengue fever is not dangerous if we're good at protecting aganist it. That begins by checking your house so there's no area with water where the common house mosquito can lay eggs. Then go to the nearby public health clinic to get pesticide powder and mix it in the water to kill common mosquitoes if eggs are found in standing water."