Faecal examinations for helminth eggs were performed on 1869 people from two riverside localities, Vientiane Municipality and Saravane Province, along the Mekong River, Laos. To obtain adult flukes, 42 people positive for small trematode eggs (Opisthorchis viverrini, heterophyid, or lecithodendriid eggs) were treated with a 20-30 mg kg-1 single dose of praziquantel and purged. Diarrhoeic stools were then collected from 36 people (18 in each area) and searched for helminth parasites using stereomicroscopes. Faecal examinations revealed positive rates for small trematode eggs of 53.3% and 70.8% (average 65.2%) in Vientiane and Saravane Province, respectively. Infections with O. viverrini and six species of intestinal flukes were found, namely, Haplorchis taichui, H. pumilio, H. yokogawai, Centrocestus caninus, Prosthodendrium molenkampi, and Phaneropsolus bonnei. The total number of flukes collected and the proportion of fluke species recovered were markedly different in the two localities; in Vientiane, 1041 O. viverrini (57.8 per person) and 615 others (34.2 per person), whereas in Saravane, 395 O. viverrini (21.9 per person) and 155207 others (8622.6 per person). Five people from Saravane harboured no O. viverrini but numerous heterophyid and/or lecithodendriid flukes. The results indicate that O. viverrini and several species of heterophyid and lecithodendriid flukes are endemic in these two riverside localities, and suggest that the intensity of infection and the relative proportion of fluke species vary by locality along the Mekong River basin.
Bibliographical noteFunding Information:
We are grateful to Dr Sithat Insisiengmay and the staff of the Center for Laboratory and Epidemiology, Department of Hygiene and Prevention, Ministry of Public Health, Vientiane, and staff at the Station of Malariology and Parasitology, Saravane Provincial Health Department, Saravane, Lao PDR, for their help during the collection of faecal samples from villagers and for the preparation of Kato-Katz smears. We also thank the staff of the Korea Association of Health Promotion, Seoul, Republic of Korea, who participated in the Korea-Laos Cooperation Project on Parasite Control in Lao PDR (1999–2004). This study was supported by BK21 Human Life Sciences, Ministry of Education, Republic of Korea.
All Science Journal Classification (ASJC) codes
- Animal Science and Zoology