Detection of Opisthorchis viverrini Infection among the ASEAN Population in Thailand Using a Verbal Screening Test and Fecal Concentrator Kit.

BACKGROUND: Opisthorchis viverrini is a serious health problem in Southeast Asia. The infection is associated with cholangiocarcinoma. Therefore, this study was aimed to detect O. viverrini infections among the ASEAN population in Thailand. METHODS: A cross-sectional study was conducted among 249 individuals from ASEAN populations in Thailand including Thai, Laotian, Cambodian, and Myanmar. Participants were screened using the O. viverrini verbal screening test (OvVST). Fecal samples were processed by the mini-parasep sf parasite fecal concentrator. RESULTS: The infection rate of O. viverrini was 27.21%. The majority of infections was detected in females, in the age group 31-40 yr old, in the primary school education level, and in the occupation of labor. By country, O. viverrini infection was detected more often in the Lao PDR (30.77%). In screening for O. viverrini infection, OvVST had a high sensitivity (93.48%), specificity (86.70%), NPV (98.32%), and accuracy (87.95%). The PPV was 61.43% for OvVTS. The observed agreement was substantial for OvVST (k-value = 0.64). CONCLUSION: O. viverrini infections are still detected in ASEAN countries therefore large scale active surveillance is required. OvVST had a high sensitivity, specificity, and accuracy for screening the risk groups for O. viverrini.

Re-Examination of Opisthorchis viverrini in Nakhon Ratchasima Province, Northeastern Thailand, Indicates Continued Needs for Health Intervention.

Opisthorchis viverrini infection is associated with cholangiocarcinoma particularly in the cases of chronic or re-infection. This presents a serious health problem in northeastern and northern Thailand. A community base approach is required for surveillance. Therefore, in a pilot project, re-examination of O. viverrini infection was conducted in the 3 districts of Nakhon Ratchasima province, Thailand, during June and October 2015. A total of 355 participants from a 194,152 population, was selected through multi-stage sampling. O. viverrini infection was determined using modified Kato Katz thick smear technique. Participants were 229 males and 126 females, and aged ≥30 years old. Prevalence of O. viverrini infection was 2.25% (8/355 participants). O. viverrini infection was slightly higher in females (3.17%), and age group between 41-50 years (4.49%). Mueang Yang district had a highest of O. viverrini infection rate (2.82%), and followed by Bua Yai (2.48%), and Chum Phuang (1.84%), respectively. O. viverrini infection rate was increased from year 2012 to 2015 particularly in Bua Yai and Mueang Yang. These re-examinion results indicate that opisthorchiasis is still problem in community of Nakhon Ratchasima province, therefore, the provincial-wide scale is need required. Furthermore health education is need intervened in the infected group, and screening of cholangiocarcinoma is urgently concerned.