Weeraya Phupiewkham1,2,3, Rutchanee Rodpai1,2, Somchith Inthavongsack4, Sakhone Laymanivong5, Tongjit Thanchomnang6, Lakkhana Sadaow1,2, Patcharaporn Boonroumkaew1,2, Oranuch Sanpool1,2, Penchom Janwan7, Pewpan M Intapan2, Wanchai Maleewong1,2. 1. D epart ment of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand. 2. Excellence in Medical Innovation, and Technology Research Group, Faculty of Medicine and Mekong Health Science Research Institute, Khon Kaen University, Khon Kaen 40002, Thailand. 3. Department of Science and Mathematics, Faculty of Science and Technology, Rajamangala University of Technology Tawan-ok, Chonburi 20110, Thailand. 4. Malaria and Helminth Control Center, Thakhek and Health Khammouane Province, Khammouane Province 12000, Lao PDR. 5. Center of Malariology, Parasitology and Entomology, Ministry of Health, Vientiane Capital 01000, Lao PDR. 6. Faculty of Medicine, Mahasarakham University, Maha Sarakham 44000, Thailand. 7. Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80161, Thailand.
Abstract
BACKGROUND: Human opisthorchiasis, caused by Opisthorchis viverrini, is a public health problem in Southeast Asia and a major risk factor for cholangiocarcinoma. In Lao PDR, seroprevalence and the relationship between the number of O. viverrini eggs in infected people and specific antibody responses are still unknown. We evaluated and compared parasitological and serological screening methods in the community in an endemic area of opisthorchiasis in Lao PDR. METHODS: Seroprevalence of O. viverrini-specific total IgG and IgG4 antibodies and their relationships with O. viverrini egg intensities were evaluated in Khammouane Province, central Lao PDR, using ELISA and a modified formalin ethyl-acetate concentration technique (FECT). RESULTS: FECT stool examination revealed O. viverrini eggs in 70.3% (90/128) of individuals (95% CI 61.6 to 78.1%) while ELISA (based on total IgG and on IgG4 antibodies to O. viverrini) found 98.4% (95% CI 94.5 to 99.8%) and 89.8% (95% CI 83.3 to 94.5%) of sera, respectively. There was a positive and significant correlation between numbers of O. viverrini eggs per gram and levels of both IgG (R2=0.168, p<0.001) and IgG4 (R2=0.219, p<0.001) antibodies. CONCLUSIONS: A high prevalence of human opisthorchiasis in Lao PDR was found using a new platform, serological screening in the community. This points to a need for sustainable control of this liver fluke infection.
BACKGROUND: Human opisthorchiasis, caused by Opisthorchis viverrini, is a public health problem in Southeast Asia and a major risk factor for cholangiocarcinoma. In Lao PDR, seroprevalence and the relationship between the number of O. viverrini eggs in infected people and specific antibody responses are still unknown. We evaluated and compared parasitological and serological screening methods in the community in an endemic area of opisthorchiasis in Lao PDR. METHODS: Seroprevalence of O. viverrini-specific total IgG and IgG4 antibodies and their relationships with O. viverrini egg intensities were evaluated in Khammouane Province, central Lao PDR, using ELISA and a modified formalin ethyl-acetate concentration technique (FECT). RESULTS: FECT stool examination revealed O. viverrini eggs in 70.3% (90/128) of individuals (95% CI 61.6 to 78.1%) while ELISA (based on total IgG and on IgG4 antibodies to O. viverrini) found 98.4% (95% CI 94.5 to 99.8%) and 89.8% (95% CI 83.3 to 94.5%) of sera, respectively. There was a positive and significant correlation between numbers of O. viverrini eggs per gram and levels of both IgG (R2=0.168, p<0.001) and IgG4 (R2=0.219, p<0.001) antibodies. CONCLUSIONS: A high prevalence of human opisthorchiasis in Lao PDR was found using a new platform, serological screening in the community. This points to a need for sustainable control of this liver fluke infection.