Dengue fever and dengue hemorrhagic fever
These diseases are endemic in South East Asia. They are caused by dengue virus bite from the bite of aedes mosquito that lives in the houses and their neighbourhood. This mosquito bites during the daytime.
Dengue infection in local people, mostly children, often results in fever with bleeding skin and other organs (dengue hemorrhagic fever) which is sometimes fatal; but for travellers from non-endemic areas, the infection usually manifests itself as fever with a skin rash, severe headache and muscle pain (dengue fever) which is usually non-fatal.
This disease is most common during the rainy season (May to September) and precautions should be taken against mosquito bites. Ones who are ill with symptoms suspected of dengue infection should seek medical consultation to establish the cause of the illness.
This is mainly caused by the ingestion of contaminated food or water, avoid food not properly cooked and drink boiled, bottled or carbonated water.
Diarrhoea causes considerable loss of body fluids and electrolyte solution should be taken. If diarrhoea persists for 12-24 hours you should consult a physician.
Food served at street vendors should be considered at risk. Fresh vegetable and fruits should be adequately washed with clean water. Fresh salad should only be taken from a salad bar or a restaurant of hygienic standard. Tap water in many Southeast Asian cities are claimed to be safe for drinking, but it is still advisable to stick to safety precautions.
It is now practically unknown in Thailand. However, if travelling in mountainous and border areas precautions should be taken and preventatives are available at any drug store or pharmacy but most chemoprophylactic drugs have proven to be ineffective.
Tourists visiting these endemic areas are recommended to take general precautions against mosquito bites. Those who develop fever within two weeks of entry to risk areas should seek prompt medical examination and treatment.
Rabies can be found in dogs (and some mammals). The situation has improved but travellers are recommended to take prevention if their travel itineraries allow possible exposure to animal bites.
Those who plain walking sight-seeing in local communities should consider having
pre-exposure rabies vaccinations before starting off. Three intramuscular injections of cell-culture rabies vaccines are required.
In case of exposure to animals without prior vaccination, the pre-exposure vaccination is usually effective if initiated without delay. However for those who have had pre-exposure vaccination if they are bitten should also seek prompt consultation with the physician for evaluation and consideration for booster vaccination.
Sexually transmitted diseases and HIV/AIDS
Urethritis remains the most common treatable sexually transmitted disease (STD) among tourists to Asia. Gonorrhoea from Southeast Asia is frequently multi-drug resistant whilst syphilis is becoming less common.
HIV/AIDS is spreading at worrisome speeds in most Asian countries, resulting mostly from unprotected sexual contacts. Promiscuous sex anywhere can be dangerous.
For travellers, local sex workers, either explicit or concealed are potential sources of STD and HIV/AIDS. All casual sex should be avoided or strictly protected with the use of condoms.
There are two major groups of viral hepatitis. Hepatitis spread by contaminated food and water; hepatitis A and E are endemic in many parts of Asia.
Most local people are immune to these types of hepatitis through natural infection, but travellers from better hygienic environments can be receptive to infection. Therefore, travellers are recommended to practice prevention measures against food and water borne diseases, as suggested for diarrhoea. An alternative protection for hepatitis A is the immunization with hyper-immune serum or hepatitis A vaccine.
Another group of hepatitis; hepatitis B, C and D, are transmitted through contaminated blood and sexual contacts or passed from infected mothers to their babies at the time of the birth; similar to the ways HIV/AIDS is transmitted. This group of hepatitis can be simultaneously and effectively avoided if precautions against HIV/ Aids are strictly taken. However for those ho require immunisation, effective against hepatitis B is available at most medical services.