The following intestinal and tissue parasites are found in this region. The ones with an (*) are more common and may infect an occasional risk to the traveler:
This intestinal parasite can cause chronic diarrhea and weight loss. It is diagnosed by a stool examination and is easily treatable. Transmission is by contaminated food and water.
HOOK WORM AND STRONGYLOIDIASIS*
These worms are transmitted by walking barefoot on fecally contaminated soil. They can cause mild diarrhea, abdominal pain and low grade chronic blood loss. Hook worm infestation is diagnosed by a stool exam and are treatable.
Amoeba are also intestinal parasites transmitted by contaminated food and water. They can invade the intestine and liver and cause serious problems such as severe dysentery and liver abscess. Amoebiasis is still a common disease in neighboring countries such as India, Nepal and Bangladesh but rare in Thailand. Diagnosis is by stool exam, blood tests and ultrasound (if in the liver). Effective treatment is available.
Trichinellae are tissue parasites that are most commonly transmitted to man from poorly cooked pork (bear meat is an occasional offender in North America). In Thailand and neighboring countries (mostly Laos) it is eating of poorly cooked pork sausages that has caused outbreaks. The last two outbreaks involving expatriates and locals were at two Western Embassy garden parties in Vientienne, Laos. Trichinosis is a serious disease characterized by swelling of the face and muscles, fever and muscle pain. The diagnosis is by muscle biopsy. Treatment is available. Prevention is by avoiding poorly cooked meats (mostly pork but also reported in horses, turtles, crocodiles and even some wild birds)
LIVER FLUKE DISEASE
Small liver flukes (ophistorchis) are common in the Northeast of Thailand and in Laos. They are transmitted by eating raw or pickled freshwater fish; a delicacy to local residents. Transmission to travelers is exceedingly rare. Treatment is available. Japanese Sashimi, eaten in a good restaurant, has been made from frozen ocean fish and is generally safe.
Paragonimiasis does still exist in Thailand but is rare. This fluke is transmitted by eating poorly cooked freshwater shrimp, crab or crayfish. The mature worm settles in the lung and causes blood streaked cough and areas of pneumonia. It is rare in expatriates.
OTHER RARE PARASITES
Tape worm disease is not uncommon. Poorly cooked meat and fish are the risks that should be avoided. Diagnosis is by stool exam and treatment is effective.
Schistosomiasis is now rare but is best avoided by not swimming where it has still been reported (some Northeastern lakes and rivers). Treatment is available.
Filariasis is still present in some remote regions of Thailand, Malaysia and in Cambodia where cases among expatriates have been seen. Manifestations are fever and swollen lymph nodes. The disease is diagnosed by blood tests and effective treatment is available.
Larva migrans or various manifestations of “creeping eruption” are also seen in this region. The dog hook worm is a risk for visitors who walk barefoot on beaches contaminated by dogs feces. Several internal “wandering worms” are more serious but easily avoided. Gnathostomiasis is transmitted by poorly cooked fish, duck or chicken. Angylostrongyliasis (the rat lung worm) is rarely seen and causes a form of meningitis (eosinophilic meningitis) in man. It is transmitted by raw or poorly cooked fish and crab meat. Treatment for the latter two infestations is not very satisfactory and they are best avoided by watching what you eat.