Prevalence and Associated Risk Factors of Intestinal Parasitic Infections: A Population-Based Study in Phra Lap Sub-District, Mueang Khon Kaen District, Khon Kaen Province, Northeastern Thailand.

Intestinal parasitic infections are still a crucial problem among communities in Northeast Thailand. Misuse of antiparasitic drugs and unhealthy food behaviors are known. This study aimed to explore the prevalence, behavioral health factors, and motivation for self-treatment of anti-parasitic drugs in this area. A community-based cross-sectional study was conducted in Phra Lap sub-district, Mu Khon Kaen district, Khon Kaen province, Northeast Thailand, in 2016. A total of 419 participants were recruited to complete a self-administered questionnaire and stool examination. Binary logistic regression was used to assess the association between the risk factor and parasitic infection. Forty-two participants (10%; 95%CI 7.5-13.3) were positive for at least one parasite species. In this community, the most detected intestinal parasite was Opisthorchis viverrini (5.3%), followed by Strongyloides stercoralis (3.1%). A total of 67.5% of the participants had the experience of anti-parasitic drug treatment within previous 1 year, and "Often eat raw food" was the most common reason for the use of anti-parasitic drugs. On multivariate analysis, parasitic infections were significantly associated with male gender (ORadj. 2.42; 95%CI 1.00-5.85), age ≥ 60 years (ORadj. 7.55; 95%CI 1.60-35.76), and often consuming raw food of at least one type (ORadj. 2.37; 95%CI 1.03-5.44). Given these findings, correction of the dietary habit of eating raw fish/meat, which is the most important measure, and limitation of the use of anthelmintic treatment for individuals with stools positive for ova as well as emphasis on sanitary toilets will be implemented for the prevention and control of parasitic infection in endemic communities.

Inhibitory Effect of Aspirin on Cholangiocarcinoma Cells

Aspirin and other non-steroidal anti-inflammatory drugs reduce the risk of cancer due to their anti-proliferative and apoptotic effects, which are the important mechanisms for their anti-tumor activity. Here, the effect of aspirin on human cholangiocarcinoma cells (KKU-214) and the underlying mechanisms of its action were explored. Cell proliferation was measured by sulforhodamine B (SRB) assay, while cell cycle distribution and apoptosis were determined by flow cytometry. Western blotting was used to explore protein expression underlying molecular mechanisms of anti-cancer treatment of aspirin. Aspirin reduced cell proliferation in a dose- and time-dependent manner, and altered the cell cycle phase distribution of KKU-214 cells by increasing the proportion of cells in the G0/G1 phase and reducing the proportion in the S and G2/M phases. Consistent with its effect on the cell cycle, aspirin also reduced the expression of cyclin D1 and cyclin­dependent kinase 4 (Cdk-4), which are important for G0/G1 cell cycle progression. Treatment with aspirin led to increased induction of apoptosis in a dose-dependent manner. Further analysis of the mechanism underlying the effect of this drug showed that aspirin induced the expression of the tumor-suppressor protein p53 while inhibiting the anti-apoptotic protein B­cell lymphoma-2 (Bcl-2). Correspondingly, the activation of caspase-9 and -3 was also increased. These findings suggest that aspirin causes cell cycle arrest and apoptosis, both of which could contribute to its anti-proliferative effect.

A combination of praziquantel and the traditional medicinal plant Thunbergia laurifolia on Opisthorchis viverrini infection and cholangiocarcinoma in a hamster model.

Cholangiocarcinoma (CCA) associated by Opisthorchis viverrini remains a health problem in Southeast Asia including Thailand. At present, there is still no efficient treatment for CCA. Thunbergia laurifolia is a traditionally used medicinal plant; its aqueous leave extract possesses the antioxidant activity and anti-inflammatory on hamster opisthorchiasis had been reported previously. Here, we demonstrate the combined effects of the T. laurifolia extract plus antihelminthic drug, praziquantel (PZ) on hamsters with opisthorchiasis and hamsters with opisthorchiasis related-cholangiocarcinoma through light microscopic observations of histopathological changes, as well as liver function tests for alanine transaminase (ALT) and alkaline phosphatase, and kidney function tests for blood urea nitrogen and creatinine. Results showed T. laurifolia extract combined with praziquantel reduced inflammatory cell aggregation and inhibiting CCA development, which were correlated to the serum ALT level. These present studies suggest that administration of T. laurifolia after praziquantel treatment clearly improve the hepatobiliary system and could reduce the risk of subsequent CCA development in human.

Does a combination of opisthorchiasis and ethyl alcohol consumption enhance early cholangiofibrosis, the risk of cholangiocarcinoma?

Combination of Opisthorchis viverrini infection and other factors could drive cholangiocarcinoma (CCA) development in Southeast Asia. However, other CCA factors are obscure. Alcohol consumption is well known in the risk for several cancers, but there is no report in CCA development. Therefore, the present study was to clarify whether drinking alcohol increases the liver pathology of Opisthorchis viverrini (OV) infection which may be the CCA risk. Experimental Syrian hamsters were divided into two groups: (1) infected with OV alone (OV); and (2) infected with OV plus administration of drinking alcohol (OV + ALC) for various lengths of time, i.e., 1, 2, 3, and 6 months. Hamster livers were collected for analysis of histopathological changes through hematoxylin and eosin, Sirius red, and immunohistostaining for proliferating cell nuclear antigen (PCNA) and cytokeratin 19 (CK19). Syrian hamster sera were used for liver function tests. Observed histopathological changes consisted primarily of aggregations of inflammatory cells surrounding the hepatic bile duct, especially at the hilar region, in both OV and OV + ALC groups; however, there was a difference in virulence. The OV + ALC group showed greater severity than the OV group. Moreover, in addition to aggregations of inflammatory cells, new bile duct formation (including hepatic cell death) was observed in subcapsular hepatic tissue. Bile duct proliferation, as determined by positive immunohistochemical staining for CK19 and PCNA, was correlated with the histopathology. Increased fibrosis was observed in subcapsular liver tissue. The present study suggests that alcohol consumption can exacerbate cholangiofibrosis, cholangitis, and lithiasis, which are risk factors for CCA.

Tumor-related gene changes in immunosuppressive Syrian hamster cholangiocarcinoma.

The results of a previous study demonstrated that prednisolone enhanced cholangiocarcinogenesis. Therefore, to clarify molecular changes during immunosuppressive cholangiocarcinogenesis, Syrian hamsters were divided into 8 groups: uninfected controls; immunosuppressed Syrian hamsters using prednisolone (P); normal Syrian hamsters administered N-nitrosodimethylamine (ND); immunosuppressed Syrian hamsters administered N-nitrosodimethylamine (NDis); normal Syrian hamsters infected with Opisthorchis viverrini (OV); immunosuppressed Syrian hamsters infected with O. viverrini (OVis); normal Syrian hamsters infected with O. viverrini and administered N-nitrosodimethylamine (CCA); and immunosuppressed Syrian hamsters infected with O. viverrini and administered N-nitrosodimethylamine (CCAis). Syrian hamster livers were used for analysis of tumor-related gene expression and immunohistochemistry through cytokeratin 19 (CK19) and proliferating cell nuclear antigen (PCNA) staining. The tumor-related gene expression results show that CCAis groups at all time points exhibited upregulation of COX-2, IL-6, SOD1, CAT and iNOS and downregulation of p53, which correlated with the predominant expression of CK19 and PCNA in liver tissue. These results suggest that prednisolone enhances cholangiocarcinoma development, which was confirmed by molecular changes.

Alcohol and alkalosis enhance excystation of Opisthorchis viverrini metacercariae.

The northeastern region of Thailand has long been known as an endemic area of the human liver fluke infection which is caused by Opisthorchis viverrini. Humans are infected by ingestion of uncooked cyprinoid fish in traditional dishes such as "koi-pla," "pla-som," "pla-jom," and "pla-ra." To date, the prevalence of this parasite infection remains high because of cultural behavior and local beliefs. The popular misunderstanding among people in this area is that alcohol, lemon juice, and fish sauce can kill the parasites. Thus, they believe that they can eat raw fish without the risk of infection. This study attempts to clarify the effects of ethyl alcohol and acidosis-alkalosis on O. viverrini metacercariae excystation. Metacercariae of O. viverrini were obtained from infected cyprinoid fish in a natural reservoir. Most metacercariae were obtained from small cyprinoid fish. Metacercariae were divided into three experimental groups and were treated with solutions containing four different concentrations of ethyl alcohol, four different concentrations of salt, and a range of acidic/basic pH. Metacercariae excystation was observed at the assigned times, and the data were then analyzed. Salt had no effect on excystation. Interestingly, the optimal conditions for O. viverrini excystation were pH 9 and 25 % ethyl alcohol. The present study suggests that raw fish should not be eaten while drinking alcohol or when consuming other ingredients with pH 9, because both alcohol and pH 9 could induce O. viverrini metacercariae excystation, leading to the early development of parasites in the hepatobiliary system.

A cross-sectional study on intestinal parasitic infections in rural communities, northeast Thailand.

Despite the existence of effective anthelmintics, parasitic infections remain a major public health problem in Southeast Asia, including Thailand. In rural communities, continuing infection is often reinforced by dietary habits that have a strong cultural basis and by poor personal hygiene and sanitation. This study presents a survey of the prevalence of intestinal parasitic infections among the people in rural Thailand. The community-based cross-sectional study was conducted in villages in Khon Kaen Province, northeastern Thailand, from March to August 2013. A total of 253 stool samples from 102 males and 140 females, aged 2-80 years, were prepared using formalin-ethyl acetate concentration methods and examined using light microscopy. Ninety-four individuals (37.2%) were infected with 1 or more parasite species. Presence of parasitic infection was significantly correlated with gender (P=0.001); nearly half of males in this survey (49.0%) were infected. Older people had a higher prevalence than younger members of the population. The most common parasite found was Opisthorchis viverrini (26.9%), followed by Strongyloides stercoralis (9.5%), Taenia spp. (1.6%), echinostomes (0.4%), and hookworms (0.4%). The prevalence of intestinal protozoa was Blastocystis hominis 1.6%, Entamoeba histolytica 0.8%, Entamoeba coli 0.8%, Balantidium coli 0.4%, Iodamoeba bütschlii 0.4%, and Sarcocystis hominis 0.4%. Co-infections of various helminths and protozoa were present in 15.9% of the people. The present results show that the prevalence of parasitic infections in this region is still high. Proactive education about dietary habits, personal hygiene, and sanitation should be provided to the people in this community to reduce the prevalence of intestinal parasite infections. Moreover, development of policies and programs to control parasites is needed.