Epidemiology of food-borne trematodes and other parasite infections in a fishing community on the Nam Ngum reservoir, Lao PDR.

Food-borne trematodes (FBT) are important causes of parasitic infections in many Asian countries. Parasitological surveys in Xai Udom, a small fishing community on the Nam Ngum reservoir, Lao People's Democratic Republic, revealed an overall parasitic infection rate in May 1999 of 68.8% (n = 173) and in December 1999 of 65.9% (n = 261). The liver fluke, Opisthorchis viverrini accounted for most of the infections (prevalences of 53.8% and 42.1%, during the first and second surveys, respectively). The prevalence and intensity showed increasing trends with age. Minute intestinal flukes were also present but with relatively low infection rates (3.8-10.9%). The second common group of parasites comprised soil-transmitted nematodes, Trichuris trichiura, Ascaris lumbricoides, hookworm and Strongyloides stercoralis, with prevalences of 22.4 and 17.6%, 20.8 and 8.0%, 16.8 and 13.4%, and 4.0 and 15.3% (first and second surveys, respectively). Most people had no or only light infections, with a few people having heavy infections. Coexisting intestinal protozoa were Giardia lamblia (5.2 and 4.9%) and Entamoeba coli (6.9 and 6.5%). Concurrent tapeworm infections were Taenia (1.7 and 1.1%) and Hymenolepis nana (0.7 and 0.6%) (first and second surveys, respectively). Despite the availability of effective anthelmintic drugs, the results of our study reaf-firm that FBT are still a major health threat in this fishing area of Lao PDR, similar to a decade ago.

Enzyme markers to identify and characterize Opisthorchis viverrini in Thailand and Lao PDR.

We conducted an allozyme electrophoretic study to explore potential enzyme markers to distinguish Opisthorchis viverrini in Thailand and Lao PDR. Twenty-eight enzymes encoding presumptive 32 loci were established. The enzymes glucose-6-phosphate dehydrogenase and pyruvate kinase were diagnostic between two geographically separate isolates from Thailand. Twelve enzymes, ie, aconitate hydratase, aldolase, creatine kinase, enolase, esterases, fumarate hydratase, aspartate aminotransferase, glucose-phosphate isomerase, alanine aminotransferase, isocitrate dehydrogenase, malic enzyme, and pyruvate kinase, also provided diagnostic markers for these two isolates from Thailand and one isolate from Lao PDR.