• Parasites, Hosts and Diseases
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• v.61 no.4
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• pp.463-470
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• 2023

This study aimed to identify the recent risk factors for Opisthorchis viverrini infection and cholangiocarcinoma (CCA) to improve disease prevention. The participants were divided into the following 3 groups based on their health status: healthy control (nonOV and nonCCA), those with O. viverrini infection (OV), and those with CCA. A questionnaire was used to explore their lifestyle and behaviors. Multivariate logistic regression and backward elimination were used to identify the significant risk factors. The results showed that the significant risk factors for both O. viverrini infection and CCA were age>50 years (odd ratio (OR)=8.44, P<0.001, 95% confidence intervals (CI) 2.98-23.90 and OR=43.47, P=0.001, 95% CI 14.71-128.45, respectively) and raw fish consumption (OR=8.48, P<0.001, 95% CI 3.18-22.63 and OR=3.15, P=0.048, 95% CI 1.01-9.86, respectively). A history of O. viverrini infection was identified as an additional risk factor for CCA (OR=20.93, P=0.011, 95% CI 2.04-215.10). This study provided an update on the risk factors for O. viverrini infection and CCA. Asymptomatic patients with O. viverrini infection, particularly those>50 years old, should be carefully monitored to prevent CCA.

• Parasites, Hosts and Diseases
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• v.51 no.6
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• pp.767-769
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• 2013

Opisthorchiasis, a risk factor for cholangiocarcinoma in humans, is of public health importance in Thailand. The Annual Surveillance Reports from Nan and Lampang Provinces, Thailand, for the year 2011 showed an opisthorchiasis prevalence of over 70% by recovery of eggs in the feces. This study investigated whether most cases are actually due to minute intestinal flukes (MIF) rather than Opisthorchis viverrini, as the eggs of both can hardly be differentiated by morphology. Fifty and 100 cases from residents in Nan and Lampang, respectively, had stools positive for eggs initially assumed to be those of O. viverrini. Each patient was given praziquantel at 40 mg/kg in a single dose. After 2 hr, 30-45 ml of the purgative magnesium sulfate was given, and stools were collected up to 4 times sequentially. The stools were examined for adult worms by simple sedimentation. It was found that 39 of 50 cases (78.0%) from Nan Province had Haplorchis taichui, with intensities ranging from 5 to 1,250 with an average of 62 worms/case. Taenia saginata (7 cases) and Enterobius vermicularis (1 case) were other helminths recovered as the co-infectants. In Lampang Province, H. taichui was recovered from 69 cases (69.0%). The number of flukes recovered ranged from 1 to 4,277, with an average of 326 worms/case. Four cases had Phaneropsolus bonnei, and 10 T. saginata as the co-infectants. Adult specimens of O. viverrini were not recovered from any stool. Clearly, MIF infection, especially haplorchiasis, is more common in northern Thailand. These findings should encourage the Public Health Office to employ more specific tools than Kato's method for surveillance of opisthorchiasis in Thailand.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.16
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• pp.6609-6612
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• 2014

Opisthorchis viverrini is an ongoing public health problem in Northeast Thailand. Despite continuous efforts for decades by healthcare organizations to overcome this problem, infection rates remain high. To enable related personnel to identify and address the various issues effectively, a cross-sectional study was performed to investigate prevalence and risk factors for opisthorchiasis. The target group was 3,916 Thai residents of Northeast Thailand who were 15 or over. Participants were recruited using the 30 clusters sampling technique. The data were gathered through questionnaires, focus group discussions, in-depth interviews, and stool examinations for parasite eggs (using the Modified Kato Katz method). The data were analyzed using descriptive and inference statistics; in order to ascertain the risk factors and test them using the odds ratio and multiple logistic regressions. The prevalence of opisthorchiasis was 22.7% (95%CI: 0.26 to 0.24). The province with the highest prevalence was Nakhorn Phanom (40.9%; female to male ratio =1:1.2). The age group with the highest prevalence was 40-49 year olds. All age groups had a prevalence >20%. Four of seven provinces had a prevalence >20%. The factors related to opisthorchiasis were (a) sex, (b) age (especially > 50), (c) proximity and duration living near a water body, and (d) eating raw and/or fermented fish. In order to reduce the prevalence of opisthorchiasis, the focus in populations living in upper Northeast Thailand should be changing their eating behaviors as appropriate to their tradition and context.

• Parasites, Hosts and Diseases
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• v.58 no.4
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• pp.475-479
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• 2020

Tegumental and excretory-secretory proteins are reported as diagnostic antigens for human opisthorchiasis. Rhophilin associated tail protein1-like (OvROPN1L) protein of Opisthorchis viverrini sperm tail showed potential as a diagnostic antigen. The OvROPN1L recombinant fragments were assayed for diagnostic antigenicity for human opisthorchiasis using indirect ELISA. The strongest antigenic region was a N-terminus peptide of M1 - P56. One synthetic peptide (P1, L3-Q13) of this region showed the highest antigenicity to opisthorchiasis. Sera from other parasitic infections including Strongyloides stercoralis, hookworm, Taenia spp, minute intestinal flukes, Paragonimus spp showed lower reactivity to P1. Peptide P1 is located in the disordered N-terminus of ROPN1L supporting its suitability as linear epitope. In the Platyhelminthes the N-terminal sequence of ROPN1L is diverging with taxonomic distance further suggesting that peptide P1 has potential as diagnostic tool in the genus Opisthorchis/Clonorchis. It should be further evaluated in combination with peptides derived from other O. viverrini antigens to increase its diagnostic power.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.1
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• pp.281-283
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• 2016

The Cholangiocarcinoma is a. The risk of development of cholangiocarcinoma, generally a rare type of a liver tumor, increases during infection of Opisthorchiasis. For this reason the timely detection of Opisthorchiasis is important for Cholangiocarcinoma prevention. There are many studies which concern the detection of pathogenesis of Opisthorchis viverrini infection but a little known about Opisthorchis felineus. In this study we investigate a correlation of the eggs which are found in a faeces and are comparable with a serum Ig G and Ig M antibody level that were detected with ELISA test in a large group of patients. The result is showing positive correlation between evidence of the Opisthorchis felineus eggs that were found in a faeces and antibody Ig G and Ig M level in a serum. Moreover the combination of two methods can improve the Opisthorchiasis diagnostic: the serum antibody and faeces investigation of eggs.

• Parasites, Hosts and Diseases
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• v.58 no.5
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• pp.527-535
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• 2020

To clarify the reinfection profile associated with risk factors of opisthorchiasis, we conducted an epidemiological study on the chemotherapeutic effects on reinfection with O. viverrini in the endemic areas of Northeastern Thailand for 3 years. A total of 3,674 fecal samples were collected from participants in villages of 5 provinces. They were examined microscopically using a modified technique of formalin ethyl-acetate concentration. Egg-positive residents were reexamined year (2018) by year (2019) after treatment with a single dose (40 mg/kg) of praziquantel. Health education was provided to the participants yearly. The egg-positive rate of O. viverrini was 14.3%, and was highest (22.2%) in the 20-30 year-old group in 2017. The egg positive rate was 15.3% in dogs and 11.4% cats. Human reinfection rate was 15.5% and 6.3% in next 2 years, and was highest (23.2%) among the fishermen. Relative risk factors of reinfection were significantly higher for males, over 40-year-old age, or working as fishermen or farmers, and eating uncooked fish within the preceding year. A significant difference resulting from a health education program was observed in the third year. Therefore, health education and sustainable surveillance for opisthorchiasis should be maintained to decrease the risk of reinfection.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5443-5447
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• 2014

The cholangiocarcinoma (CCA) is a relatively rare cancer worldwide but it is highly prevalent in Thailand where the liver fluke, Opisthorchis viverrini is endemic. There are reports that interleukin 6 (IL-6) may play an important role in the pathogenesis of opisthorchiasis associated CCA. Functionally, IL-6 can act on target cells through its receptor, IL-6R, and IL-6R polymorphisms may affect the functional activity of IL-6 leading to susceptibility to cholangiocarcinogenesis. Therefore, we assessed the association of the 48892 A/C (Asp358Ala) polymorphism in exon 9 of the IL-6R gene in 79 CCA cases compared to 80 healthy controls using the PCR-RFLP technique. The results showed significant differences between CCA cases and controls in overall genotype (p=0.001) and allele frequencies (p=0.0002). Chi-square for trend test revealed a significant association between genotype and CCA susceptibility (p=0.0002). The odds ratios (ORs) for genotype were 0.283 (95% CI=0.131-0.605, AC vs. AA; p=0.0003) and 0.206 (95% CI=0.196-1.245, CC vs. AA; p=0.0416), the OR for alleles was 0.347 (95% CI=0.187-0.633, allele C vs. allele A; p=0.0002) and that for the carrier C variant was 0.272 (95% CI=0.130-0.564; p=0.0001). This study demonstrated a close association between an IL-6R polymorphism, specifically higher A allele, and cholangiocarcinoma.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1111-1114
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• 2016

Opisthorchiasis is a major problem in Thailand particularly in northeast region which also has a high incidence of cholangiocarcinomas. Since health modification is needed, this quasi-experimental study aimed to assess the effectiveness of a health education program based on self-efficacy and social support in Tha Tum district, Surin province, Thailand. A total of 70 participants were purposive selected with a history of opisthorchiasis. Participants were divided into experimental and control groups, each with 35 subjects. The experimental group received a health education program composed of: (1) knowledge improvement, lectured with multimedia, demonstration, brochure, and handbook; (2) group discussion about their health beliefs, sharing their ideas and experience; and (3) social support from village health volunteers (VHV), heads of villages (HV), friends, and members of families, and public health officer (PHO). Follow-up was by PHO/VHV/HV, with provision of certificates and flasg for household that did not eat raw fish. Data were collected by predesigned questionnaires after implementation of the program for 3 months. Comparative data was analyzed by paired simple t-test and independent t-test. The results revealed that the experimental group had mean score of knowledge higher more than before the experiment (mean difference=3.1, t=3.915, 95%CI-3.3, -1.8 p-value=0.001), and the control group (mean difference=2.5, t=4.196, 95%CI=1.4, 3.6, p-value=0.001) with statistical significance. The mean scores of practice were higher than before the experiment (mean difference=4.6, t=4.331, 95%CI-5.3, -3.1, p-value=0.001), and control group (mean difference=4.4, t=6.142, 95%CI=4.2, 7.9, p-value=0.001). The mean scores of perceived susceptibility and perceived severity of opisthorchiasis, al well as perceived benefits and perceived barriers to prevention of opisthorchiasis, were also higher than before the experiment and in the control group (p-value <0.001). In conclusion, this was a successful health education program for liver fluke avoidance. Therefore, it may useful for further behavior modification in the other epidemic areas.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1293-1297
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• 2016

Cholangiocarcinoma (CCA) is a serious problem in Thailand, particularly in the northeastern and northern regions. Database of population at risk are need required for monitoring, surveillance, home health care, and home visit. Therefore, this study aimed to develop a geographic information system (GIS) database and Google map of the population at risk of CCA in Mueang Yang district, Nakhon Ratchasima province, northeastern Thailand during June to October 2015. Populations at risk were screened using the Korat CCA verbal screening test (KCVST). Software included Microsoft Excel, ArcGIS, and Google Maps. The secondary data included the point of villages, sub-district boundaries, district boundaries, point of hospital in Mueang Yang district, used for created the spatial databese. The populations at risk for CCA and opisthorchiasis were used to create an arttribute database. Data were tranfered to WGS84 UTM ZONE 48. After the conversion, all of the data were imported into Google Earth using online web pages www.earthpoint.us. Some 222 from a 4,800 population at risk for CCA constituted a high risk group. Geo-visual display available at following www.google.com/maps/d/u/0/edit?mid=zPxtcHv_iDLo.kvPpxl5mAs90&hl=th. Geo-visual display 5 layers including: layer 1, village location and number of the population at risk for CCA; layer 2, sub-district health promotion hospital in Mueang Yang district and number of opisthorchiasis; layer 3, sub-district district and the number of population at risk for CCA; layer 4, district hospital and the number of population at risk for CCA and number of opisthorchiasis; and layer 5, district and the number of population at risk for CCA and number of opisthorchiasis. This GIS database and Google map production process is suitable for further monitoring, surveillance, and home health care for CCA sufferers.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.5
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• pp.1751-1758
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• 2015

There has been a strong, positive correlation between opisthorchiasis-associated cholangiocarcinoma and infection with Helicobacter. Here a rodent model of human infection with Opisthorchis viverrini was utilized to further investigate relationships of apparent co-infections with O. viverrini and H. pylori. A total of 150 hamsters were assigned to five groups: i) Control hamsters not infected with O. viverrini; ii) O. viverrini-infected hamsters; iii) non-O. viverrini infected hamsters treated with antibiotics (ABx); iv) O. viverrini-infected hamsters treated with ABx; and v) O. viverrini-infected hamsters treated both with ABx and praziquantel (PZQ). Stomach, gallbladder, liver, colonic tissue, colorectal feces and O. viverrini worms were collected and the presence of species of Helicobacter determined by PCR-based approaches. In addition, O. viverrini worms were cultured in vitro with and without ABx for four weeks, after which the presence of Helicobacter spp. was determined. In situ localization of H. pylori and Helicobacter-like species was performed using a combination of histochemistry and immunohistochemistry. The prevalence of H. pylori infection in O. viverrini-infected hamsters was significantly higher than that of O. viverrini-uninfected hamsters ($p{\leq}0.001$). Interestingly, O. viverrini-infected hamsters treated with ABx and PZQ (to remove the flukes) had a significantly lower frequency of H. pylori than either O. viverr-iniinfected hamsters treated only with ABx or O. viverrini-infected hamsters, respectively ($p{\leq}0.001$). Quantitative RT-PCR strongly confirmed the correlation between intensity H. pylori infection and the presence of liver fluke infection. In vitro, H. pylori could be detected in the O. viverrini worms cultured with ABx over four weeks. In situ localization revealed H. pylori and other Helicobacter-like bacteria in worm gut. The findings indicate that the liver fluke O. viverrini in the biliary tree of the hamsters harbors H. pylori and Helicobacter-like bacteria. Accordingly, the association between O. viverrini and H. pylori may be an obligatory mutualism.