A comparative study of Helicobacter pylori infection in hamsters experimentally infected with liver flukes Opisthorchis felineus, Opisthorchis viverrini, or Clonorchis sinensis.

Helicobacter pylori causes a wide range of human diseases including cancer. Carcinogenic foodborne trematodes Opisthorchis viverrini, Clonorchis sinensis, and O. felineus might promote transmission and spread of H. pylori infection in the definitive mammalian host, which in turn might contribute to the liver fluke-associated malignancy. Our objectives were to find out whether liver flukes O. felineus, O. viverrini, and C. sinensis are carriers of Helicobacter pylori and to determine whether H. pylori is present in feces, bile, and stomach samples from the experimentally infected hamsters. We found that liver flukes are not reservoirs of H. pylori. Nevertheless, the prevalence of H. pylori and the H. pylori ureA gene copy number were significantly elevated after the infection. Overall, although the liver flukes O. felineus, C. sinensis, and O. viverrini are not reservoirs of H. pylori, the infection with the liver flukes significantly modifies the biliary and gut microbiota by increasing H. pylori abundance. This may be a feature of any liver fluke pathogenesis that have not previously been taken into account. Our findings appear to be novel in terms of comparative assessment of the host microbiota and Helicobacter abundance during epidemiologically important liver fluke infections.

Social network analysis of food sharing among households in opisthorchiasis endemic villages of Lawa Lake, Thailand.

Consumption of raw fish is a well-documented risk factor for Opisthorchis viverrini infection. Sharing of food, especially raw fish recipes may influence the spread of disease through a community. Using social network analysis of an ego network, we investigated food sharing among households in an Opisthorchis-endemic area. Network centrality properties were used to explain the differences in O. viverrini transmission and control between villages with a low and high prevalence of infection. Information on demography and O. viverrini infection in 2008 from villagers in the Lawa Lake area was extracted from the Tropical Disease Research Center database. The two villages that had the lowest and the highest O. viverrini infection at the household level were recruited. Ten percent of households of each village were randomly sampled. Participatory epidemiology and face-to-face structured interviews guided by a social network questionnaire were used to collect data on livelihood, agricultural patterns, food sources, raw fish eating habits, and other food sharing during daily life and social gatherings. The number of contacts including in-degree and out-degree varied from 0 to 7 in the low-infection village and 0 to 4 in the high-infection village. The mean number of contacts for the food-sharing network among the low- and high-infection villages was 1.64 and 0.73 contacts per household, respectively. Between these villages, the mean number of out-degree (p=0.0125), but not in-degree (p=0.065), was significantly different. Food-sharing differed in numbers of sharing-in and sharing-out between the two villages. Network analysis of food sharing may be of value in designing strategies for opisthorchiasis control at the community level.

The carcinogenic liver fluke Opisthorchis viverrini is a reservoir for species of Helicobacter.

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≤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. viverrini- infected hamsters treated only with ABx or O. viverrini-infected hamsters, respectively (p≤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.

[Parasitocenotic relationships in the marita micropopulations of Opisthorchis and opportunistic microorganisms (an in vitro model)].

The purpose of this investigation was to determine the relation of exometabolites of Opisthorchis maritas and the bacteria Klebsiella pneumoniae and Staphylococcus aureus, by studying some physiological functions of mature Opisthorchis and the properties of bacteria in the artificial media during co-cultivation. Its modified procedure was used to examine tile hature of relationships in the micro- population of the parasite and opportunistic bacteria. The Opistorchis felineus maritas obtained from the liver of an infested animal were the object of helminthological examinations. Co-cultivation of the bacteria Klebsiella pneumoniae and Staphylococcus aureus with Opistorchis felineus maritas showed that the latter exerted some inhibitory effects on the growth and reproduction of bacteria; moreover, there were no changes in their biochemical processes, virulence factors; and antibiotic susceptibility.

[Opisthorchiasis in the Ob-Irtysh river basin: etiology and pathogenesis].

Opisthorchiasis in the hyperendemic focus (Ob-Irtysh river basin) is considered to be a co-member of parasitocenosis: opisthorchiasis + methorchiasis and to have a superinvasive form. The symbiotic flora and O. felines metabolites are an etiopathogenetic flora. Scientific evidence is provided for the recurrent forms ofopisthorchiasis; the authors consider it to be the type of superinvasive opisthorchiasis, in which some portion of parasites in microballs unexposed to antheminthics further mature to maritae.