Parasitic infections in Thai workers that pursue overseas employment: the need for a screening program

Stool examination is a requirement of the screening program for Thai workers seeking overseas employment. We report on the prevalence of intestinal parasitic infections among these workers; the stool examination results of 2,213 Thai workers who visited the Out-patients Department of the King Chulalongkorn Memorial Hospital between September 2000 and January 2001 were analysed. One hundred and thirty-five (6.1%) were found to be infected with 1 or 2 species of parasite. There were 54 (40%), 47 (34.8%), and 25 (18.5%) cases infected with nematodes, platyhelminths and protozoa, respectively. The commonest parasite was Opisthorchis viverrini (28.9%). Most nematode infections were due to Strongyloides stercoralis (19.2%); most protozoal infections were due to Giardia lamblia (17.0%). Mixed infections were found in 9 cases. Not unexpectedly, the rate of intestinal parasitic infection among Thai workers remains high. Screening for the parasitic infections among these workers can help to decrease their rate of rejection by the countries in which overseas employment is sought.