In the present study, a simple, economic and practical technique was employed for stool examination. Of a total of 6,146 fecal samples from foreign workers in Northern Taiwan between 1999 and 2000 were examined, 615 were found to be positive for parasitic infection and the overall infection rate was 10%. Newly arriving foreign workers had a significantly higher infection rate (15%) than those who had worked in Taiwan for 6-12 months (8%). The foreign workers came from Indonesia, Philippines, Thailand, Malaysia, and Vietnam. Except for the small number of workers from Malaysia which was not included, the infection rate order by nationality was Vietnamese (21%) > Indonesian (13%) > Philippino (10%) > Thai (4%). The female examined workers were about 3-fold of males and their infection rate (11%) was also significantly higher than the males (5%). The order of rates by age was 20-30 years (11%) > 31-40 years (8%) > 41-50 years (5%). According to the species of parasites, 569 foreign workers were infected with 1 species (9%) > with 2 species (0.7%) > with 3 species (0.1%). Totally, 14 species (10 helminths including 1 plant nematode, Heterodera and 4 protozoa; hookworm might include 2 or 3 species, but counted as one species here) were found, of which 10 species were pathogenic (9 helminths and 1 protozoa) and 4 non-pathogenic. Foreign workers from Indonesia harbored 12 species of parasites > from the Philippines, 9 species > from Thailand, 8 species > from Vietnam, 7 species.
In the past year, stool specimens of 1,732 alien laborers were examined for intestinal parasites. There was no significant difference in the positive rate between males and females. All alien laborers were examined in 3 hospitals and the positive rates were 24.8% (191/769), 13.6% (109/804) and 12.6% (20/159). Broken down by nationality, the positive rates in laborers from Thailand, Indonesia, the Philippines and Malaysia were 23.9% (192/803), 20.3% (62/305), 12.1% (60/498) and 4.8% (6/126) respectively. Of all alien laborers, 17.2% (297/1,732) had single infections of parasites and 1.3% (23/1,732) had multiple infections. Opisthorchis viverrinii was the most prevalent parasite found in infected alien laborers. 91.5% of alien laborers were aged from 21 to 40-years-old and had positive rates of parasites reaching 91.0%. The time of arrival in Taiwan had an effect in all alien laborers examined for parasites. The positive rate in laborers arriving during April to June was 22.7% which was significantly higher than the 16.3% for laborers arriving in other months.