The antigenic characterizations and serological reactions of human liver flukes, Clonorchis sinensis and Opisthorchis viverrini, were analyzed by immunoblot. The antigenic profiles of the crude extract of Clonorchis contained major proteins of 8, 26-28, 34-37, 43, and 70 kDa, and those of Opisthorchis 34-37, 43, 70, and 100 kDa. Of these, the 8, 26-28 and 34-37 kDa bands of Clonorchis and the 100 kDa of Opisthorchis were major components of each excretory-secretory antigen. The 8 and 26-28 kDa bands were specific to Clonorchis but the 100 kDa of Opisthorchis cross-reacted with the sera of clonorchiasis, and the 34-37, 70 and 100 kDa bands cross-reacted with sera of other helminthiases. The frequency and intensity of the immunoblot reactions were positively correlated with the intensity of the liver fluke infection.
Animals ; Antigens, Helminth/analysis/*chemistry/immunology ; Clonorchiasis/*diagnosis ; Clonorchis sinensis/*immunology ; Cross Reactions ; Electrophoresis, Polyacrylamide Gel/veterinary ; Humans ; Immunoblotting/veterinary ; Molecular Weight ; Opisthorchiasis/*diagnosis ; Opisthorchis/*immunology

To increase public health awareness for prevention of opisthorchiasis caused by eating raw freshwater fish, the distribution and abundance of Opisthorchis viverrini metacercariae (OV MC) was investigated in freshwater fish obtained from 20 provinces in northeastern Thailand between April 2011 and February 2012. A cross-sectional survey was conducted on 12,890 fish consisting of 13 species randomly caught from 26 rivers, 10 dams, and 38 ponds/lakes. Fish, were collected in each of the rainy and winter seasons from each province. Fish were identified, counted, weighed, and digested using pepsin-HCl. Samples were examined for OV MC by a sedimentation method, and metacercariae were identified under a stereomicroscope. OV MC were found in 6 species of fish; i.e., Cyclocheilichthys armatus, Puntius orphoides, Hampala dispar, Henicorhynchus siamensis, Osteochilus hasselti, and Puntioplites proctozysron from localities in 13 provinces. Among the sites where OV MC-infected fish were found, 70.0% were dams, 23.7% were ponds/lakes, and 7.7% were rivers. The mean intensity of OV MC ranged from 0.01 to 6.5 cysts per fish (or 1.3-287.5 cysts per kg of fish). A high mean intensity of OV MC per fish (>3 cysts) was found in 5 provinces: Amnat Charoen (6.5 cysts), Nakhon Phanom (4.3), Mukdahan (4.1), Khon Kaen, (3.5) and Si Sa Ket (3.4). In conclusion, OV MC are prevalent in natural cyprinid fish, with the infection rate varying according to fish species and habitats.
Animals ; Cross-Sectional Studies ; Cyprinidae/*parasitology ; Fish Diseases/*epidemiology/*parasitology ; Metacercariae/*isolation & purification ; Microscopy ; Opisthorchiasis/epidemiology/parasitology/*veterinary ; Opisthorchis/*isolation & purification ; Parasitology/methods ; Prevalence ; Thailand

Objective: To determine the influence of geographic, knowledge and behavioral factors on Opisthorchis (O.) viverrini infection in the Northeast of Thailand. Methods: This cross-sectional study was conducted by using four datasets of years 2016 and 2017. Generalized linear mixed model was employed to analyze association between geographic, knowledge and behavioral factors and O. viverrini infection. Results: Totally there were 1 885 participants. The prevalence of O. viverrini infection was 10.03%. Geographic factors that showed statistically significant association with O. viverrini infection in the Northeast region were featured by at least a dam and reservoir (Adj. OR = 4.21, 95%CI: 2.49-7.13, P < 0.001), at least a weir (Adj. OR = 1.74, 95%CI: 1.09-2.77, P = 0.020), > 50 dogs and cats per village (Adj. OR = 3.40, 95%CI: 2.17-5.31, P < 0.001), and rice fields covered > 50% of its areas (Adj. OR = 1.91, 95%CI: 1.04-4.01, P = 0.036), as well as low to moderate levels of knowledge (Adj. OR = 1.60, 95%CI: 1.32 to 1.94, P < 0.001), consumed raw fish (Adj. OR = 1.90, 95%CI: 1.02 to 3.52, P = 0.040) and consumed processed raw fish (Adj. OR = 3.03, 95%CI: 2.20 to 4.18, P < 0.001). Other significant covariates were gender and age of the respondents. Conclusions: O. viverrini infection still remains a public health problem of the Northeast of Thailand. Geographic and demographic factors, knowledge, and consumption behaviors of raw fish products are significantly associated with O. viverrini infection.