Malaria is a parasitic disease spread by mosquitoes.  It causes high fever with chills, headache, abdominal discomfort and, in severe cases, rapid coma and death.  Falciparum malaria (malignant tertian) is the most common and feared form in this part of the world.  Vivax malaria is less severe but has the ability to recur if not properly treated.  Other forms of malaria (Falciparum ovala and malariae as well as some monkey strains)  are extremely uncommon in this region.  The mosquitoes which spread malaria in Thailand bite mostly at dusk and at night.  Malaria is endemic on the Burmese border (including Kanchanaburi Province), the Laos and Cambodian border regions and in pockets throughout the country including several islands in Trad province.  It is not a danger in the cities such as in Bangkok, Pattaya, Hua Hin, Phuket, Kho Samui, Songkhla and Chiangmai.  The majority of visitors to the Kingdom are thus not exposed and need not take any preventive medications for malaria.  However,  individuals who take nocturnal jungle trips and boat trips or stay on the islands off Trad as well as those going to neighboring countries may be  at risk and should obtain instruction regarding the best current preventive measures.


PRIMARY MALARIA PREVENTION

Repellents make humans unattractive to a mosquito so that it will avoid areas of the body that have been treated with the product. Repellents do not kill mosquitoes. The best repellents will provide protection from bites for a long period of time from just one application. Repellents that are currently available are either synthetic chemicals, such as DEET, or plant derived chemicals such as Citronella. Various formulations of these repellents are available that differ in the amount of active ingredient, which is the substance that actually repels the mosquito. These products are available as sprays, wipe-on's, sticks, foams, and lotions.
In 2005, the US-CDC  added   Oil of Lemon-Eucalyptus [p-menthane 3,8-diol (PMD)]. The oil of lemon eucalyptus has not been tested against mosquitoes that spread malaria and some other diseases which occur internationally. The label for oil of lemon eucalyptus specifies that it should not be used on children under 3 years of age.

SECONDARY PROPHYLAXIS:

This is done by taking a drug that kills the malaria parasites when they are introduced into you by a mosquito bite.  This used to be safe and easy worldwide when Chloroquine was still effective.  Chloroquine is no longer effective against the dangerous strain of malaria (Plasmodium falciparum) in almost all of Asia, the Pacific Islands, Africa and South America. Even vivax malaria is becoming resistant to it in parts of Indonesia and Papua and possibly other places. Other drugs recommended for malaria prevention are: Maloprim, Daraprim, Paludrin, Daraclor, Camoquin, Flavoquin and Fansidar.  None of these are effective in Thailand and they should not be used here as they give the traveler a false assurance that they are protected.  Travelers to India and Bangladesh should be warned that malaria is present there in many cities as well as the countryside.  If you are planning to camp outdoors in malarious areas of Asia you should take either Doxycycline, or Mefloquine (Lariam) as a preventative. Malarone is also effective but very expensive and not available in Asia.

SHORT  TERM MALARIA PROPHYLAXIS FOR TRAVELERS TO SE ASIA:

Doxycycline 100 mg once daily will  prevent Malaria in Thailand.  This drug belongs to the Tetracycline family and may cause photosensitivity on exposure to sun (a bad rash) in rare individuals.  It should also not be taken by those who are pregnant and by children under the age of ten years.  The dose is one tablet daily and should be started several days prior to and continued for 4 weeks after leaving a malarious area.

Mefloquine (Lariam) 250 mg once weekly should be started 1-2 weeks before entering the malaria infested area and continued for 4 weeks after departure.  Inserts supplied with the drug still state that it should not be used during pregnancy and in children.  However, it has been used in both groups in this region without any identified serious problems.  It has the reputation of causing bad dreams in some subjects.

Malarone (Atovaguone+Prognanil)
Is not available in Thailand.  It has to be taken daily and is available in Europe and North America.

Neither doxycycline nor mefloquine (or any other drugs presently used) are 100% effective and cases of severe malaria have been reported in users.  Therefore, even if you have taken doxycycline or mefloquine, any fever that occurs during or after your stay in a malaria endemic region should be considered as malaria till proven otherwise.  Consult a doctor and get a blood smear examination as soon as possible!  These tests are available in all health centers and hospitals in Thailand.  The most effective prophylaxis against malaria is avoidance of being bitten by mosquitoes and this is what the Thai Ministry of Health stresses for residents and visitors.