Intestinal parasites among the Southeast Asian laborers in Taiwan during 1993-1994

A large number of foreign laborers are now working in Taiwan, the majority coming from Southeast Asia where parasitic infections are common. Since 1992, monitoring the intestinal parasitic infections of these foreigners has been carried out, particularly to prevent the introduction of some of the parasites into Taiwan. This paper reports results obtained during the year 1993-1994.

The merthiolate-iodine-formalin (MIF) concentration method was used to detect intestinal parasites; and the data were analyzed by chi 2-test.

Among the 3,020 persons examined, 526 (17.4%) were infected and 14 kinds of parasites were identified; i.e. Ascaris lumbricoides, Trichuris trichiura, Strongyloides stercoralis, Enterobius vermicularis, hookworms, Taenia sp., Opisthorchis viverrini, Fasciolopsis buski, Schistosoma japonicum, an echinostome, Entamoeba histolytica. Entamoeba coli, Endolimax nana and Giardia lamblia. By nationality, those workers from Indonesia had the highest infection rate, at 32.3%; they were followed by the Filipinos (18.7%), the Thais (16.6%) and the Malaysians (8.0%). The three or four most prevalent parasites were T. Trichiura (21.8%), A. lumbricoides (5.6%) and hookworms (2.4%) for the Indonesians; T. Trichiura (9.1%), A. lumbricoides (3.7%), hookworms and E. histolytica (2.1% each) for the Filipinos; O. viverrini (8.4%), hookworms (3.3%) and E. histolytica (1.2%) for the Thais; T. trichiura (2.2%), A. lumbricoides and E. histolytica (1.8% each) and hookworms (1.4%) for the Malaysians. Among the 526 persons infected, 92.2% had 1 species, 7.2% had 2 species, 0.4% had 3 species and 0.2% had 4 species of parasites.

The present result, a 17.4% infection rate, was significantly higher (p < 0.05) than the 12.3% obtained for the previous year (1992-1993). E. histolytica was found in 34 persons, 16 of whom were working as live-in housemaids. The epidemiological significance of some parasites is discussed here.