High endemicity of Opisthorchis viverrini infection among people in northern Cambodia confirmed by adult worm expulsion

Abstract

Opisthorchis viverrini infection is an emerging disease in Cambodia, especially in central and southeastern areas. However, its status in northern areas bordering Lao PDR has been relatively unknown. The present study was performed to investigate the status of O. viverrini infection among people in Preah Vihear and Stung Treng provinces through fecal examination to detect eggs and recovery of adult flukes from some of the egg-positive cases. Fecal examinations were performed on a total of 1101 people from 10 villages in the 2 provinces using the Kato-Katz thick smear technique. For recovery of adult flukes and other helminth parasites 10 volunteers positive for eggs of Opisthorchis viverrini and/or minute intestinal flukes (Ov/MIF), in Kampong Sangkae village, Preah Vihear province, were administered a single oral dose of 40 mg/kg praziquantel plus 5–10 mg/kg of pyrantel pamoate and purged with 40–50 g magnesium salts. Adult trematodes, together with nematodes and cestodes expelled in diarrheic stools were collected under a stereomicroscope or with the naked eye. The proportion of egg-positive cases for overall liver and intestinal helminths was high but not notably different between the 2 provinces, 65.5% in Preah Vihear versus 64.7% in Stung Treng. The average proportion of Ov/MIF egg-positive cases was 59.8%. A total of 315 adult specimens of O. viverrini were recovered from the 10 volunteers (4–98 specimens per individual; mean, 32). A smaller number of Haplorchis taichui adults, an intestinal fluke, were found mixed-infected in 7 (103 specimens in total; 1–31 per individual; mean, 15) of the 10 volunteers. Adult specimens of hookworms, Enterobius vermicularis, Trichostrongylus sp., and a Taenia tapeworm strobila were recovered in some cases. Based on the results, it has been confirmed that the surveyed areas in Preah Vihear and Stung Treng provinces, Cambodia, are highly endemic areas of O. viverrini infection with a low-grade mixed infection with H. taichui.

Molecular identification of Opisthorchis viverrini among the northeastern Cambodian population by internal transcribed spacer 2 based polymerase chain reaction

“…The very recently study was conducted to investigate the ranking of O. viverrini infection in the Preah Vihear and Stueng Treng Provinces through fecal samples. The highest prevalence was (59.8%) of eggpositive cases among population in theses provinces that found to be highest increasing ever reported in Cambodia (Jung et al, 2023). However, according to Korean researcher team was reported about a nationwide survey by highest prevalence of O. viverrini infection in Kampong Cham (24.0%), Takeo (23.8%), and lower prevalence followed by Preah Vihear (2.7%), Stung Treng (2.5%), Kratie (3.4%), and (2.8%) Ratanakiri Province, respectively.…”

“…In 2013, there was countrywide research of the students that funded by USAID in Cambodia to determine the prevalence infection caused by O. viverrini in children was found (4.10%) (Khieu et al, 2019;Lee et al, 2002). However, one of recently investigation of O. viverrini infection in Preah Vihear and Stung Treng Province was prevalence higher by the age group 30-39 years and followed by age group 40-49, 50-59, and over 60 years, whereas the prevalence was lower among children under 9 years, age group 10-19, and 20-29 years (Jung et al, 2023). Their finding was similar trended of liver fluke infections that have been seen in other nations, including O. viverrini in Lao PDR and Thailand (Forrer, 2012;Suwannahitatorn et al, 2019;Pengput, 2020), O. felineus in Russia (Rim et al, 2003), and C. sinensis in South Korea (Rim et al, 1990).…”

“…In the present study, no significant sex difference was noted. One of the reasons may be that the major source of infection in the surveyed areas is traditional fish dishes popularly consumed by the people regardless of gender, such as 'plea tre' (fish salad), 'plea tre chou' (sour fish salad), and 'ma'am' (fermented fish, kept for 2-5 days) (Jung et al, 2023).…”

“…The epidemiology of liver fluke infection varies by endemic area, where foodborne trematode infection is widespread, especially in connection to the attitude of consumer culture and lifestyle. One of the reasons may be that the major source of infection in the surveyed areas is traditional fish dishes popularly consumed by the people regardless of gender, such as 'plea tre' (fish salad), 'plea tre chou' (sour fish salad), and 'ma'am' (fermented fish, kept for 2-5 days) (Jung et al, 2023). The classification of risk factors for liver fluke infection based on parasitological and molecular testing is another frequent claim made in studies of demographics.…”

“…The very recently study was reported that the standing of O. viverrini and/or minute intestinal flukes (MIFs) infection among population from 10 villages in Preah Vihear and Stung Treng Province with the average prevalence 59.8% of egg-positive cases. Thus, liver flukes, O. viverrini infection is an emerging disease in the northeastern cross the central to southern provinces (Jung et al, 2023).…”