Mixed Eimeria and Cryptosporidium infection and its effects on pathology and clinical outcomes in juvenile Asian seabass (Lates calcarifer) cultured in Thailand

Coccidiosis is an important disease in juvenile fish because of severe intestinal injury during infection. We first reported the mixed infection of intestinal coccidia and its association with health status and pathological findings in juvenile Asian seabass (Lates calcarifer) cultured in Thailand. Two groups of Asian seabass, 60-day fish and 90-day fish, were sampled to investigate prevalence and coccidian infection intensity using morphological characterization and PCR. Phylogenetic analysis of 18S rRNA gene amplified from the intestines revealed Eimeria sp. and Cryptosporidium sp. infection. The prevalence of Eimeria sp. and Cryptosporidium sp. in sampled fish was 100%. Clinical outcomes assessed, using health assessment index (HAI) scoring and semi-quantitative grading of intestinal lesions and inflammation, demonstrated that all fish developed variety of pathology and clinical illness; however, infection intensity in 60-day fish was significantly higher (p < .05) than 90-day fish. The HAI score of 60-day fish was poorer than 90-day fish, which correlated to a high infection intensity (r = .397), analysed by Pearson correlation coefficient. Overproduction of intestinal oxidants contributing to mucosal injury was examined by nitrotyrosine expression. The high production of reactive nitrogen species indicated severe inflammatory response, and intestinal injuries occurred mainly in the 60-day fish.

Association between Opisthorchis viverrini infection in cats and humans: Non-spatial and spatial analyses

Cats are recognized as significant reservoir hosts for human opisthorchiasis, particularly in areas with a high prevalence of infection. Despite this, the precise role of cats in the transmission of Opisthorchis viverrini between humans and felines remains unclear. This study investigates the association between these two hosts through both spatial and non-spatial analyses in the endemic Thanya sub-district of Thailand. A total of 105 owned cats were randomly sampled from 15 villages within the sub-district for stool examination. A questionnaire was administered to 66 cat owners to explore the human-pet relationship. Household locations were collected using GPS devices. Non-spatial analyses revealed a positive association between the two hosts (P= 0.011; OR 7, 95% CI: 1.6-30.9), highlighting two independent significant risk factors: cat owners consuming raw fish (P = 0.028; OR = 4.52, 95% CI: 1.25-19.45) and feeding cats raw fish (P = 0.011; OR = 16.41, 95% CI: 2.78-317.04) according to multivariate analysis. Spatial analysis provided further support to the non-spatial findings (p = 0.0123; OR = 3.45, 95% CI = 0.88-13.61). Multiple autologistic regression confirmed two significant risk factors: cat owners consuming raw fish (p = 0.054; OR = 3.37, 95% CI: 0.98-11.59) and feeding cats raw fish (p = 0.014; OR = 7.43, 95% CI: 1.49-37.05). Risk mapping identified the western part of the study site as a hotspot for O. viverrini infection. Hyper-endemic focusing revealed a union of human and cat buffers at 0.46 km², with an overlapping area of 0.22 km² (47.83%). This study underscores the impact of owners' behaviors, specifically consuming and feeding raw fish to cats, on the increased probability of infection in cats. It emphasizes the need for effective opisthorchiasis control through health education targeting cat owners in endemic areas.

Feline leptospirosis prevalence worldwide: A systematic review and meta-analysis of diagnostic approaches

Background and Aim

Leptospirosis in felids (domestic and wild cats) presents an ongoing challenge in our understanding. Numerous studies have reported the detection of Leptospira spp. in these feline populations, highlighting their potential as zoonotic carriers. This systematic review and meta-analysis aimed to provide insight into the global prevalence of leptospirosis in domestic and wild cats.

Materials and Methods

We conducted extensive searches across five databases (PubMed, Scopus, Web of Science, Science Direct, and Google Scholar) following the Preferred Reporting Items for Systematic Reviews and Meta-analyses Protocols guidelines. Random-effect meta-analyses were performed using R software version 4.3.0 to estimate pooled prevalence rates. Subgroup meta-analyses were conducted based on continents, diagnostic methods, sample types, and wildcat genera.

Results

A total of 71 articles on leptospirosis in domestic cats and 23 articles on leptospirosis in wild cats met the eligibility criteria. Our findings indicated a significantly higher pooled seroprevalence of leptospirosis in domestic cats compared with infection prevalence (9.95% [95% confidence interval (CI), 7.60%-12.54%] vs. 4.62% [95% CI, 2.10%-7.83%], p = 0.01). In contrast, no significant difference was observed in pooled seroprevalence and infection prevalence among wild cats (13.38% [95% CI, 6.25%-21.93%] vs. 2.9% [95% CI, 0.00%-18.91%], p = 0.21). A subgroup meta-analysis of domestic cats revealed significant differences in seroprevalence across continents, sample types, and diagnostic methods. On the contrary, wild cats had no significant differences in any of the subgroups.

Conclusion

Leptospira spp. have evidently been exposed to both domestic and wild cats, highlighting their potential roles as reservoir hosts for leptospirosis. These findings highlight the importance of considering felids as a possible public health threat.

Inflammatory responses to Opisthorchis viverrini infection in animal models: A comparison between susceptible and nonsusceptible hosts in different anatomical locations

Background

Inflammation caused by Opisthorchis viverrini infection increases the risk of cholangitis, cholecystitis, and leads to bile duct cancer (cholangiocarcinoma or CCA). However, only certain infected individuals are susceptible to CCA, suggesting the involvement of host factors in cancer development. In addition, there are reports indicating differences in the locations of CCA.

Aim

This study aims to investigate cellular inflammatory responses in the common bile duct (CB), intrahepatic bile duct (IHB), and gallbladder (GB) in susceptible and non-susceptible hosts following O. viverrini infection.

Methods

Thirty Syrian golden hamsters (a susceptible host) and 30 BALB/c mice (a non-susceptible host) infected with O. viverrini were studied at six time points (five animals per group). Histopathological evaluations were conducted on samples from the IHB, CB, and GB. Inflammatory cell infiltration was quantitatively assessed and compared between groups and time points. Statistical analysis was performed using one-way ANOVA, with a significance level of p < 0.05.

Results

Inflammation was significantly more pronounced in the IHB compared to the other two biliary locations. In comparison between susceptible and non-susceptible hosts, the intensity of inflammation was higher in the OV+H group than in the OV+M group (p < 0.05).

Conclusion

This study highlights the association between host response to inflammation, tissue location, and host susceptibility, with the IHB showing particular susceptibility to inflammation and pathological changes. These findings contribute to our understanding of the increased risk of CCA in susceptible hosts.

Unraveling the relationship among inflammatory responses, oxidative damage, and host susceptibility to Opisthorchis viverrini infection: A comparative analysis in animal models

Background and Aim

Opisthorchis viverrini infection-induced inflammation contributes to cholangiocarcinoma (CCA) development in humans and animals. Inflammation generates free radicals, such as reactive oxygen species and reactive nitrogen species (RNS), which damage the host's DNA. However, only 5% of O. viverrini-infected individuals develop malignancy, suggesting that variations in the inflammatory response of individuals to the parasite may influence susceptibility. Due to limitations in studying human susceptibility, we used an animal model to investigate the profiles of inflammatory reactions, oxidative burst, and irreversible DNA damage. This study aimed to explore the potential role of inflammation and RNS in causing DNA damage that may predispose susceptible hosts and non-susceptible animal models to cancer development in O. viverrini infection.

Materials and Methods

This experimental study was conducted on 30 Syrian golden hamsters (OV-H) and 30 BALB/c mice (OV-M) infected with O. viverrini, representing susceptible and non-susceptible models, respectively. Five animals per group were examined at six predetermined time points during the experiment. Biliary tract samples were systematically investigated using histopathological evaluation for inflammatory cell infiltration and immunohistochemical staining for RNS production and markers of DNA damage, including nitrotyrosine and 8-hydroxy-2'-deoxyguanosine. These features were quantified and compared among the experimental groups. Mann-Whitney U-test was used for statistical analysis, with p < 0.05 considered statistically significant.

Results

The comparison revealed that the OV-M group exhibited significantly earlier and higher rates of inflammatory cell infiltration during the acute phase, whereas the OV-H group exhibited chronic and more severe inflammation (p < 0.020). Intracellular RNS production and DNA damage were closely associated with the inflammatory response.

Conclusion

This study demonstrates differential responses in susceptible and non-susceptible models of O. viverrini infection regarding disease onset and duration, as well as intracellular RNS production and DNA damage caused by inflammation. Persistent inflammation generated oxidatively damaged DNA, which is a distinct pathological characteristic of susceptible hosts and may be critical for CCA development.

Roaming behavior of the owned domestic cats (Felis catus) with possible roles in the transmission of Opisthorchis viverrini in the endemic area in Khon Kaen, Thailand

In the endemic area of the liver fluke (Opisthorchis viverrini) infection, effective control of opisthorchiasis using One Health approaches requires transmission interruption in all hosts in the parasite life cycle. Owned domestic cats (Felis catus) are considered an important species among mammalian reservoirs. Similar to humans, household cats become infected by eating raw, contaminated fish and spread the O. viverrini eggs to the environment by defecation. In rural areas, cat owners usually feed their cats with human food or food waste, especially fish dishes. There is a high risk for cats to become infected and deposit eggs in the peri-household environment. The lack of research on domestic cats led us to study their roaming behavior, roaming range, habitat preference and risk of disease transmission. GPS loggers were harnessed to 28 domestic cats in 7 villages around Lawa Lake, the endemic area of human opisthorchiasis. All cats were examined for the O. viverrini infection status using modified formalin-ether concentration technique (MFECT) before application of the GPS device used to observe and record their roaming distance and range area. Then, composition analysis for habitat selection was performed using the location data. Additionally, cat owners were interviewed using participatory epidemiologic methods for their perceptions and knowledge about the reservoir hosts of this trematode. Our study suggested that the prevalence of O. viverrini in cats in this area has not declined appreciably in comparison with our previous study four years ago, although the treatment and control has been applied intensively in humans. The longest distance that individual cats roamed ranged from 51 to 363 meters (mean±SD = 154.48±90.71). The cats traveled tracks around their home. There was no significant difference in the average distance that cats ranged between O. viverrini infected group (154.13±72.80 meters) and the non-infected group (154.67±101.39 meters) was found. Compositional analysis suggested that the domestic cats preferred urban habitats where food and safety were probably more available. It appears that the main transmission route for infection of cats was contaminated fish fed to cats or fish that remained in their houses. Therefore, owners should refrain from feeding their cats potentially contaminated foods, food scraps and raw fish remains and prevent their cats from accessing them. Moreover, the participatory epidemiology results suggest that awareness of villagers is not enough for the effective and sustainable control of the disease.

Elevated circulating TLR4+ monocytes in patients with liver fluke Opisthorchis viverrini is associated with advanced periductal fibrosis

INTRODUCTION

Opisthorchis viverrini (Ov) infection can lead to several disease manifestations of the bile duct including advanced periductal fibrosis (APF) and the most severe complication, cholangiocarcinoma (CCA). Monocytes migrate to the infection site and differentiate into tissue macrophages to express and release molecules such as cytokines, reactive oxygen species, and growth factors. TLR4+ monocytes are classified as having a pro-tumor phenotype and secrete tumor-promoting factors. The aim of this study is to investigate the role of monocytes in the pathogenesis of opisthorchiasis.

METHODOLOGY

We used flow cytometry to measure the number of TLR4+ monocytes in the circulating blood of Ov infected patients with or without APF compared to healthy, non-Ov-infected controls.

RESULTS

We found, for the first time, that patients with AFP have elevated numbers of circulating TLR4+ monocytes when compared to patients without fibrosis and healthy individuals. Intriguingly, when we measured ROS from these monocytes, we found increased ROS production in patients with APF.

CONCLUSIONS

We propose that excessive production of ROS from these TLR4+ monocytes may lead to excessive injury of surrounding tissue and hence contribute to the pathological processes that lead to the development of advanced periductal fibrosis.

Distinctive location of piscine intestinal coccidiosis in Asian seabass fingerlings

Background and Aim:

Coccidian infection (coccidiosis) is one of the most important causes of illness and death in the fish population, including Asian sea bass. The fingerling developmental stage is sensitive to various infectious agents. Economic losses are sustained by the sea bass aquaculture industry due to coccidiosis annually. However, the related pathological changes in the Asian sea bass fingerlings’ three-part intestine remain unknown. This study aimed to investigate the Asian sea bass fingerlings’ infection rate, infection location and site, and specific pathological lesions in the small intestinal tissues in a marine cage farming operation.

Materials and Methods:

A cross-sectional study was conducted on 44 fingerling fishes. Major coccidia proportions were identified morphologically at both the macroscopic and microscopic levels. The infection number was determined based on coccidia presence at various intestinal locations and sites. All areas were assessed for pathological lesions using semi-quantitative grading. Analysis of variance was used to perform all data analyses using the SPSS software. Data were expressed as means ± standard deviation. p < 0.05 was considered statistically significant.

Results:

All Asian sea bass fingerlings studied were infected with coccidia. Enteritis and mucosal necrosis were distinct lesions found in the anterior intestine, which had the highest infection rate (49.94%), followed by the mid intestine (35.63%), and the posterior intestine (22.43%). The most common coccidian infection site was extracellular (subepithelial), followed by intracytoplasmic, and epicellular sites. Histopathological lesion determination revealed that intestinal tissue inflammation and epithelial injuries were predominantly seen in the anterior gut (p < 0.05).

Conclusion:

There was a high coccidian infection rate in Asian sea bass fingerlings from marine cage farming operations. Infection and intestinal damage at the anterior intestine, a major site, led to fingerling death. Disease prevention in the nursery should be intensive from the fingerling period to decrease the fatality rate caused by coccidia.

Effectiveness of public health interventions in reducing the prevalence of Opisthorchis viverrini: a protocol for systematic review and network meta-analysis

INTRODUCTION

The carcinogenic liver fluke Opisthorchis viverrini is a major public health problem in the Mekong basin region. The liver flukes can induce cholangiocarcinoma, a bile duct cancer that causes a significant burden of mortality and economic loss. Various public health interventions have been conducted to reduce opisthorchiasis but the prevalence of O. viverrini remains high in endemic regions. The aim is to quantify the effectiveness of public health interventions in reducing the prevalence of O. viverrini infection.

METHODS AND ANALYSIS

Seven databases (including PubMed, SCOPUS, Web of Science, EMBASE, ScienceDirect, Thai thesis database and TCI (Thai journals online)) will be searched from initiation through to 2022 to identify studies of interventions to reduce the prevalence of O. viverrini infection. The prevalence, incidence or number of O. viverrini-infected people will be used as the source of O. viverrini prevalence data. A conventional meta-analysis and a Bayesian network meta-analysis will be conducted to undertake direct and indirect comparisons of different interventions. Meta-regression will be used to determine the effect of each intervention. The risk of bias will be assessed using the Cochrane Collaboration's risk of bias tool. Heterogeneity between studies will be determined by forest plots and I2 and publication bias investigated with funnel plots and the Egger's test.

ETHICS AND DISSEMINATION

Ethical approval will not be required because this study will only use published data. The final report of this review will be disseminated through publication in a peer-reviewed scientific journal and will also be presented at relevant conferences.

PROSPERO REGISTRATION NUMBER

CRD42022323066.

Immunolocalization and functional analysis of Opisthorchis viverrini-M60-like-1 metallopeptidase in animal models

Host mucins have crucial physical roles in preventing the parasitic establishment and maturation, and also in expelling the invading parasites. However, some parasites utilize mucinase enzymes to facilitate the infection. Recently, we have identified a mucinase enzyme of the liver fluke Opisthorchis viverrini, Ov-M60-like-1, which exhibits metallopeptidase activity against bovine submaxillary mucin substrate. Here, we aimed to study the localization of this enzyme in O. viverrini and the bile duct of hamsters using immunohistochemistry and functional analysis by mucin digestion in hamsters and mice tissues. The results showed that Ov-M60-like-1 was detected strongly in the tegument, tegumental cells, vitelline glands and mature eggs with miracidium. Expression in the gut, ovary and testis of the parasite was moderate while parenchyma showed slight colour intensity. In addition, the mucinase was also detected in the host biliary epithelial cells and goblet cells surrounding the worm. The mucinase assay revealed that the Ov-M60-like-1 could digest neutral mucin in the parenchyma, testis and seminal receptacle, but not the mucin in the tegument, tegumental cells and vitelline glands of the worm. The enzyme can also digest mucin in the cholangiocytes and modified the mixture type in the bile duct goblet cells of the infected hamsters, a susceptible host. In contrast, the enzyme was unable to digest neutral, acid and mixture mucin in the bile duct of the mice, a non-susceptible host. These findings indicate that Ov-M60-like-1 may have functions in both housekeeping tasks and host–parasite interactions, especially in modification of host susceptibility.

Knockout of liver fluke granulin, Ov-grn-1, impedes malignant transformation during chronic infection with Opisthorchis viverrini

Infection with the food-borne liver fluke Opisthorchis viverrini is the principal risk factor for cholangiocarcinoma (CCA) in the Mekong Basin countries of Thailand, Lao PDR, Vietnam, Myanmar and Cambodia. Using a novel model of CCA, involving infection with gene-edited liver flukes in the hamster during concurrent exposure to dietary nitrosamine, we explored the role of the fluke granulin-like growth factor Ov-GRN-1 in malignancy. We derived RNA-guided gene knockout flukes (ΔOv-grn-1) using CRISPR/Cas9/gRNA materials delivered by electroporation. Genome sequencing confirmed programmed Cas9-catalyzed mutations of the targeted genes, which was accompanied by rapid depletion of transcripts and the proteins they encode. Gene-edited parasites colonized the biliary tract of hamsters and developed into adult flukes. However, less hepatobiliary tract disease manifested during chronic infection with ΔOv-grn-1 worms in comparison to hamsters infected with control gene-edited and mock-edited parasites. Specifically, immuno- and colorimetric-histochemical analysis of livers revealed markedly less periductal fibrosis surrounding the flukes and less fibrosis globally within the hepatobiliary tract during infection with ΔOv-grn-1 genotype worms, minimal biliary epithelial cell proliferation, and significantly fewer mutations of TP53 in biliary epithelial cells. Moreover, fewer hamsters developed high-grade CCA compared to controls. The clinically relevant, pathophysiological phenotype of the hepatobiliary tract confirmed a role for this secreted growth factor in malignancy and morbidity during opisthorchiasis.

Does Opisthorchis viverrini circulate between humans and domestic cats in an endemic area in Thailand?

The liver fluke Opisthorchis viverrini is a foodborne trematode that, in chronic infection, is a leading cause of bile-duct cancer – cholangiocarcinoma. Cats and dogs are acknowledged as reservoir hosts of this parasite. However, this assumption is based on morphological similarity of flukes recovered from these hosts, without any molecular genetic evidence. The aim of this study was to obtain molecular data from O. viverrini eggs present in feces of humans and cats in the same locality in Thanya sub-district, Kalasin, Thailand. The mitochondrial cytochrome c oxidase subunit 1 (cox1) gene was used as the marker for a population-genetic study. A DNA fragment of the cox1 gene was amplified from stool samples and subjected to nucleotide sequencing. Phylogenetic and haplotype network analyses were performed. The cox1 sequences of O. viverrini eggs from humans and cats largely formed separate clades on the phylogenetic trees, with an Fst value of 0.64 (P < 0.05), indicating largely distinct populations in the 2 species. However, 5 samples from cats were placed in the human cluster and 1 sample from a human was placed in the cat cluster. This suggests that host specificity of ‘human’ and ‘cat’ clades is not absolute. These results indicate that there are 2 populations of O. viverrini, one circulates primarily in humans and the other in cats. However, cross-transmission can occur between these 2 hosts. Taken altogether, the population-genetic evidence from this study partially supports the assumption that the cat can act as a reservoir host of O. viverrini.

Opisthorchis viverrini and Strongyloides stercoralis mono- and co-infections: Bayesian geostatistical analysis in an endemic area, Thailand

Parasitic infections caused by Opisthorchis viverrini and Strongyloides stercoralis remain a major public health threat in the Greater Mekong Sub-region. An understanding of climate and other environmental influences on the geographical distribution and emergence of parasitic diseases is a crucial step to guide targeted control and prevention programs. A parasitological survey was conducted from 2008 to 2013 and included 12,554 individuals (age between 20 and 60 years) from 142 villages in five districts in Khon Kaen Province, Thailand. Geographical information systems, remote sensing technologies and a Bayesian geostatistical framework were used to develop models for O. viverrini and S. stercoralis mono- and co-infections in areas where both parasites are known to co-occur. The results indicate that male sex, increased age, altitude, precipitation, and land surface temperature have influenced the infection rate and geographical distribution of mono- and co-infections of O. viverrini and S. stercoralis in this area. Males were 6.69 times (95% CrI: 5.26-8.58) more likely to have O. viverrini - S. stercoralis co-infection. We observed that O. viverrini and S. stercoralis mono-infections display distinct spatial pattern, while co-infection is predicted in the center and southeast of the study area. The observed spatial clustering of O. viverrini and S. stercoralis provides valuable information for the spatial targeting of prevention interventions in this area.

Helicobacter pylori GroEL Seropositivity Is Associated with an Increased Risk of Opisthorchis viverrini-Associated Hepatobiliary Abnormalities and Cholangiocarcinoma

Despite the synergistic effect of Opisthorchis viverrini and Helicobacter pylori co-infection on pathogenesis of severe hepatobiliary abnormalities (HBA) including advanced periductal fibrosis and replace with cholangiocarcinoma (CCA) have been established, the immune response to H. pylori in O. viverrini infected population has never been explored. Hence, this study aimed to investigate the antibody responses to 2 immunogenic H. pylori proteins in O. viverrini-infected patients with HBA and CCA. The risk analysis by multinomial logistic regression revealed that GroEL seropositivity was associated with higher risks of hepatobiliary abnormalities and CCA with adjusted odds ratios (95% confidence intervals) of 2.11 (95% CI=1.20-3.71, P=0.008) and 2.13 (95% CI=1.21-3.75, P=0.009), respectively. These findings indicate that GroEL seropositivity might be a biomarker for early detection of O. viverrini associated HBA and CCA.

Biliary Migration, Colonization, and Pathogenesis of O. viverrini Co-Infected with CagA+ Helicobacter pylori

Co-infection with the cagA strain of Helicobacter pylori exacerbates the pathology of human liver fluke Opisthorchis viverrini (OV) infection leading to cholangiocarcinoma. However, underlying mechanisms remain unclear. We report a significant increase in cagA-positive and cagA-negative H. pylori in the stomach, blood, bile, and in the OV worms of co-infected Syrian golden hamsters at one hour, three hours, and one month, post-infection, compared to hamsters infected with either OV or H. pylori alone. Except in the worms, H. pylori numbers declined at three months post-infection, particularly in the bile fluid of co-infected animals. Both strains of H. pylori were immunohistochemically detected in the tegument of the worm, as well as in the bile duct epithelium when co-infected with O. viverrine, but not in H. pylori infection alone. Interestingly, only the cagA-positive strain was detected in the gut of the worm. Co-infection between cagA-positive H. pylori and O. viverrini resulted in a more severe biliary pathology and decreased E-cadherin expression in vivo and in vitro than those of the cagA-negative strain. These data suggest that O. viverrini acts as a carrier of cagA-positive H. pylori and co-migrates to the bile ducts, whereas O. viverrini facilitates H. pylori colonization and enhances the biliary pathogenesis and carcinogenesis.

Investigation of possible alternate animal reservoir hosts of Opisthorchis viverrini

Chronic opisthorchiasis caused by Opisthorchis viverrini (O. viverrini) adversely affects human health and is associated with a fatal bile duct cancer (cholangiocarcinoma). Although cats and dogs are known animal reservoir hosts of opisthorchiasis, there is limited information about whether other fish-eating animals are fluke reservoirs. Wetlands along Chi River of Thailand have abundant intermediate host snails and fish for O. viverrini and diverse other animal species. This led to our investigation into whether other fish-eating animals can also become infected and be alternate reservoir hosts for human opisthorchiasis. Our preliminary study focused on the O. viverrini infection status of crab-eating or long-tailed macaques roaming in Kosumpi National Forest Park in Chi River Basin, Kosumpisai District of Mahasarakam Province, and rodents, small residential mammals and fish-eating birds living in Lawa wetland complex of Khon Kaen Province. Fecal samples of each animal were collected and modified formalin ether concentration technique was applied to identify infections. Additionally, participatory epidemiology was used to retrieve information from local communities on opisthorchiasis transmission in these animals. No O. viverrini infection was found in any fecal samples suggesting that monkeys, rodents, small residential mammals and birds in these two wetlands probably do not serve as alternate reservoir hosts of O. viverrini.

Synergistic effects of cagA+ Helicobacter pylori co-infected with Opisthorchis viverrini on hepatobiliary pathology in hamsters

Human liver fluke infection caused by Opisthorchis viverrini is associated with several biliary diseases including cholangiocarcinoma (CCA). Recently, it was discovered that the liver fluke is a reservoir of Helicobacter pylori, particularly the cagA-positive strain (cytotoxin-associated gene A) in its gut. Given that two carcinogenic pathogens are associated with CCA development, however, the role of cagA-positive H. pylori in opisthorchiasis has not been clarified. The present study was therefore aimed to investigate histopathological changes of the biliary system in hamsters co-infected with O. viverrini and cagA-positive H. pylori or O. viverrini and cagA-negative H. pylori, with controls of O. viverrini, cagA-positive H. pylori, or cagA-negative H. pylori alone, over time. Major histopathological changes were systematically investigated. All pathological features were quantified/semi-quantified and compared among the experimental groups. The results showed that O. viverrini infection groups (O. viverrini, cagA-positive H. pylori and cagA-negative H. pylori) showed a high degree of eosinophil and mononuclear cell infiltration, lymphoid aggregation and granuloma. Specifically, O. viverrini co-infected with cagA-positive H. pylori presented significantly higher inflammatory scores than O. viverrini and O. viverrini with cagA-positive H. pylori. Proliferation and adaptive lesions such as hyperplasia, goblet cell metaplasia and dysplasia were detected only in O. viverrini infection groups. Dysplasia, the precancerous lesion of CCA, was observed in the first-order bile ducts, especially where the inflammation existed and was found earlier and more severely in O. viverrini with cagA-positive H. pylori than other groups. Similarly, the BrdU (bromodeoxyuridine) proliferation index was significantly higher in O. viverrini co-infected with cagA-positive H. pylori than O. viverrini and O. viverrini with cagA-negative H. pylori groups. Periductal fibrosis was a prominent histopathologic feature in chronic infection in O. viverrini infection groups. Multiple logistic regression showed that O. viverrini co-infected with cagA-positive H. pylori and the duration of infection were the most important factors associated with periductal fibrosis (OR 3.02, 95% CI 1.02-9.29, p = 0.04 and OR 3.82, 95% CI 2.61-5.97, p<0.001). This study demonstrates that the liver fluke co-infected with cagA-positive H. pylori induces severe biliary pathology that may predispose to cholangiocarcinogenesis.

Multi-disciplinary integration of networking through the RNAS+: Research on other target diseases

In 2005, the network decided to increase its number of target diseases to include other helminthic zoonoses such as fascioliasis, clonorchiasis, opisthorchiasis, paragonimiasis and cysticercosis and in the process expanding membership to include South Korea, Vietnam, Thailand and Japan. NTDs were eventually included as awareness is heightened on these diseases affecting poor and developing countries. Researches on clonorchiasis and opisthorchiasis unravel the mechanism by which these diseases eventually predispose to cholangiocarcinoma. The liver cancer associated with these liver fluke infections necessitate the need to clarify the global burden of disease of these infections. The magnitude of these liver fluke diseases in endemic countries like China, Vietnam, Laos, Cambodia and Thailand is described. Success in elimination of lymphatic filariasis in PR China and Cambodia is highlighted to show how intensified multisectoral collaboration and strong political become strong ingredients in elimination of parasitic diseases like LF. New advances are presented that clarify species and strain differences in Fasciola spp., Paragonimus spp., Taenia spp. and Echinococcocus spp. Conventional diagnostic techniques are compared with new serologic techniques that are being developed. New control strategies such as the Lawa model are presented.

Conventional-Vincristine Sulfate vs. Modified Protocol of Vincristine Sulfate and L-Asparaginase in Canine Transmissible Venereal Tumor

Background: Vincristine (VCR) is a mono-chemotherapy for canine transmissible venereal tumor (CTVT). L-asparaginase (LAP) is usually used in combination with other drugs. Previously, LAP-VCR protocol was applied for the CTVT-VCR-resistant cases. However, there were a few reports about using this protocol since the first visit.

Aims: To firstly investigate the effectiveness of combining chemotherapy (Vincristine and L-asparaginase, VCR-LAP) in normal CTVT case. Secondly, to compare this protocol with the conventional (Vincristine, VCR) protocol before and during treatment in 24 CTVT dogs.

Materials and Methods: Clinical signs, tumor relative volume, and histopathological change [amount of CTVT cells, tumor-infiltrating lymphocytes (TILs), TILs/CTVT ratio, collagen area, and Ki-67 proliferative index (PI)] were the treatment evaluation parameters. Moreover, transcriptome analysis of apoptotic (Bcl-2, Bax), drug-resistant genes (ABCB1, ABCG2), and BCL-2 and BAX expression were also included.

Results: Both protocols gave the decreased tumor volume, increased TILs/CTVT ratios and collagen area in the mass. Interestingly, the combination protocol decreased treatment time. There were two resistant cases after treatment with VCR. The expression of Bcl-2 and Bax were decreased, and this may indicate the better response after treatment. Moreover, both drug resistant genes did not increase after treatment.

Conclusion: The main finding of this study is that the combination protocol did not only decrease treatment duration time but also gave the effectiveness of treatment outcomes in CTVT cases. Therefore, the application of the new protocol could be used by the field practitioners.

In vitro Effect of Recombinant Feline Interferon-Ω (rFeIFN-Ω) on the Primary CanineTransmissible Venereal Tumor Culture

Background: Interferons (IFNs), signaling proteins produced by host cells, are secreted in response to pathogen activity as well as to tumor cells, and display antiviral, antiproliferative, and immunomodulatory effects. Recombinant feline interferon omega (rFeIFN-ω) has in vitro growth inhibition activities on various canine and feline tumor cell lines. Canine transmissible venereal tumor (CTVT) is used as an animal model for immunotherapy due to its specific growth phase. Previous studies have usually focused on the interaction between tumor infiltrating lymphocytes (TILs) and CTVT cells. However, the specific effects of rFeIFN-ω on CTVT cells remains poorly defined.

Aims: The aims of this study, therefore, were to evaluate the in vitro effect of rFeIFN-ω on primary CTVT cells and to study the mRNA expression of apoptotic genes and drug resistance genes.

Materials and Methods: Purified CTVT cells were treated with various concentrations of rFeIFN-ω and the viability of the cultured cells was ascertained at 24, 48, and 72 h post treatment (hpt) and a dose-response curve plotted. The mRNA expression of apoptotic (BAX and BCL-2) and drug resistance (ABCB1 and ABCG2) genes was performed by reverse transcription quantitative real-time PCR at 72 hpt.

Results: rFeIFN-ω displayed an effect against CTVT cell viability, which decreasing viability in a dose-dependent manner within 72 hpt. The relative mRNA expression of BCL-2 was upregulated only at a rFeIFN-ω concentration of 10⁴ IU/100 μl. However, higher concentrations of rFeIFN-ω gave a higher level of relative mRNA expression of ABCB1 transporter gene.

Conclusion: This study provided the information of in vitro effect of rFeIFN-ω on CTVT cell viability in a dose dependent manner, as well as, the alteration of BCL-2 and ABCB1 gene expression after treatment. These results encourage future in vivo studies to evaluate the potential efficacy of this treatment in CTVT cases.

High macrophage activities are associated with advanced periductal fibrosis in chronic Opisthorchis viverrini infection

Liver fluke infection caused by Opisthorchis viverrini induces several hepatobiliary conditions including advanced periductal fibrosis (APF) and cholangiocarcinoma (CCA), but >25% of the infected population develops APF and 1% develop CCA. The innate immune response is the first line of defence, and macrophages are critical regulators of fibrosis. We hypothesized that macrophages from infected individuals have different capacities to either promote or suppress periductal fibrosis. We compared phagocytic activities of macrophages of healthy individuals and O viverrini-infected individuals ± APF, and found that macrophages from infected individuals with APF ingested significantly higher numbers of beads compared with healthy controls and O viverrini-infected individuals without APF. To further investigate proteolytic activity, we monitored real-time phagosomal proteolysis of beads conjugated to DQ-BODIPY-BSA using live cell imaging. We show that macrophages from O viverrini-infected individuals with APF also have elevated phagosomal proteolysis activity, which is consistent with their increased phagocytic activity. Additionally, stimulated ROS production by blood monocytes was higher in individuals with APF compared with healthy controls and infected individuals without APF. These results suggest that during O viverrini infection, macrophages with high phagocytic and proteolytic activities together with elevated ROS production are the phenotypes that can promote tissue damage, which results in periductal fibrosis.

Recent Advances in the Diagnosis and Detection of Opisthorchis viverrini Sensu Lato in Human and Intermediate Hosts for Use in Control and Elimination Programs

Opisthorchiasis is a neglected tropical disease, caused by infection with the fish-borne trematode Opisthorchis viverrini sensu lato that afflicts more than 10million people in Southeast Asia, including Thailand, Lao PDR, Vietnam and Cambodia. The disease is characterized by a chronic infection that induces hepatobiliary inflammation, especially periductal fibrosis, which can be detected by ultrasonography. This chronic inflammation eventually leads to cholangiocarcinoma (CCA), a usually fatal bile duct cancer that develops in approximately 1% of O. viverrini-infected individuals. In Thailand alone, CCA kills up to 20,000 people every year and is therefore of substantial public health importance. Its socioeconomic impacts on impoverished families and communities are considerable. To reduce O. viverrini-associated morbidity and CCA, the primary intervention measures focus on opisthorchiasis control and elimination. Accurate diagnoses of O. viverrini infection, in both mammalian, snail and fish intermediate hosts, are important for achieving these goals. Despite extensive efforts over several decades to find sensitive and specific diagnostics for opisthorchiasis, a simple and robust diagnostic method is still required. Here we review earlier and current developments in the search for new diagnostics for opisthorchiasis, with practical applications in the research laboratory, the clinic and the field. Of the methods currently available, the urine antigen assay shows considerable potential for the diagnosis and screening of opisthorchiasis. Nevertheless, these new assays require validation, determination of their cost-effectiveness when applied for mass screening in an endemic setting in support of policy decisions for national public health programs aimed at the control and elimination of opisthorchiasis.

Monitoring minimal residual disease in canine lymphomas treated with modified L-COP or L-CHOP protocols

Heteroduplex polymerase chain reaction for antigen receptor rearrangements (hPARR) was developed to monitor minimal residual disease (MRD) in canine B- and T-cell lymphomas treated with the modified L-COP or L-CHOP protocol. Thirty-five dogs were recruited in this study and their neoplastic lineages were determined by immunophenotyping with Pax5 and CD3. Peripheral blood leukocytes were collected prior to and during chemotherapy in weeks 4, 9 and 13 to detect MRD by hPARR. Twenty-eight dogs (80%) had B-cell lymphoma while seven dogs (20%) had T-cell lymphoma. A monoclonal band was detected in 11 cases that showed complete or partial remission before tumour relapse and no response to the current treatment without statistical difference in clinical outcomes; however, the treatment response had an association with the MRD result (P < 0.05). Modified L-CHOP prolonged median progression-free survival as compared to modified L-COP (215 days vs. 93 days; P < 0.05). Substage b had shorter progression-free survival than substage a (90 days vs. 215 days; P < 0.05). Clinical stage III affected median overall survival time when compared to clinical stages IV and V (432, 173 and 118 days, respectively; P < 0.05). hPARR could be used for screening refractory lymphoma together with lymph node measurement in routine clinical cases.

Neutralizing formaldehyde in chicken cadaver with urea and urea fertilizer solution

This study demonstrated the potential of using urea and urea fertilizer to neutralize formaldehyde (Fd) in chicken cadavers. Initially, in vitro Fd neutralization with various concentrations of urea solution (US) and urea fertilizer solution (UFS) was conducted; subsequently, 18% US and 27% UFS were selected for infusing into the formalinized chickens. The measurement at 48 hr after infusion showed that both solutions could effectively lower Fd in chicken cadavers to below a permissible exposure limit without affecting cadaveric and histological quality. In addition, neutralizing power of 18% US was approximately 1.3 times that of 27% UFS. This is the first demonstration of neutralizing potential of US and UFS against Fd both in vitro and in vivo.

Reservoir Animals and Their Roles in Transmission of Opisthorchis viverrini

Although any fish-eating mammals could be potential definitive hosts of Opisthorchis viverrini, only a few, especially cats and dogs, are actually known reservoir hosts for this parasite. Both animals usually get infected via consuming raw or undercooked contaminated fish, fish dishes or food remains from households. The infected animals sustain parasite egg spread via open environment defecation. Cats are the most important reservoir with higher prevalence rates of O. viverrini infection than dogs in endemic areas. Usually Opisthorchis-infected animals do not exhibit apparent clinical symptoms or specific abnormalities in laboratory examinations. Pathological findings in these animal reservoirs are basically similar to those seen in humans and experimental animals, namely periductal inflammation, biliary hyperplasia and periductal fibrosis. However, O. viverrini-associated cholangiocarcinoma has not yet been reported in the reservoir animals at present. Praziquantel is a treatment of choice not only for humans but also for animal reservoirs. Integrated control of opisthorchiasis in animal reservoirs is based on holistic approaches such as EcoHealth/One Health concepts. In fact integrated control of opisthorchiasis in humans in ecosystem has also proved successful, for example, the Lawa model for opisthorchiasis control in the endemic area of Khon Kaen, Thailand. Other feral and wild animals in endemic areas might also be potential reservoirs, and this requires more investigation. In addition, genetic diversity and evolution of the flukes might also influence zoonotic capability.

Update on Pathogenesis of Opisthorchiasis and Cholangiocarcinoma

Infection with the food-borne liver fluke Opisthorchis viverrini causes cholangiocarcinoma (CCA). Whereas the cause of CCA in the West remains obscure, the principal risk factor in Thailand is opisthorchiasis. Here, we review recent findings on the pathogenesis of opisthorchiasis and CCA focusing on helminth molecules/toxic metabolites, host-parasite interaction, endocytosis, immunopathology/inflammatory responses, free radical production, molecular genetic alterations, and multifactorial including coinfections driving to CCA development.

Chicken IgY-based coproantigen capture ELISA for diagnosis of human opisthorchiasis

Diagnosis of Opisthorchis viverrini infection by conventional stool examination is increasingly difficult due to the low intensity of the infection after several rounds of control programmes in endemic regions as well as coinfections with intestinal flukes. Therefore sensitive and specific diagnostic test is needed. In this study, a coproantigen sandwich ELISA using recombinant O. viverrini cathepsin F (rOv-CF) was developed. This sandwich ELISA employing chicken IgY raised against rOv-CF in combination with rabbit IgG antibody to the somatic O. viverrini antigens showed a lower detection limit (LLD) of 70ng native O. viverrini somatic antigens by spiking the parasite antigens into control feces. When applied to the diagnosis, the IgY-based sandwich ELISA exhibited sensitivity and specificity of 93.3% and 76.7%, respectively, in an investigation of 90 human cases positive or negative for opisthorchiasis. The positive predictive value (PPV) and negative predictive value (NPV) for this coproantigen detection were 66.7% and 95.2%, respectively. This IgY-based sandwich ELISA using parasite cathepsin F detection shows a promising immunodiagnostic alternative for human opisthorchiasis in endemic regions.

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.

Risk factors for Clonorchis sinensis infection transmission in humans in northern Vietnam: A descriptive and social network analysis study

Clonorchis sinensis is major fish-borne trematode, endemic in North Vietnam. Risk factors described so far include individual eating behaviors and environmental factors. Here, additional to conventional risk factors, we report on socially influenced liver fluke transmission in endemic communities. A cross-sectional study on risk factors and fish sharing networks was conducted in 4 villages of Gia Thinh Commune, Ninh Binh Province. A total of 510 residents in 272 households were recruited for risk factor analysis while 220 households, 28 fishermen and 10 fish-sellers were enrolled for social network study. Fecal examination for C. sinensis eggs was performed. Average C. sinensis infection rate at Gia Thinh commune was 16.5% (range 2% to 34.4%). Higher infection rates were significantly associated with males, lower educational levels, eating raw fish, and location of the villages. Social network analysis (SNA) showed a strong positive correlation between ego network size (number of households in fish sharing network) and quantity of raw fish consumed (r=0.603, P<0.05). The infection rate in people who ate raw-fish caught from a nearby river was significantly higher than those who consumed fish taken from farmed ponds (P<0.05). The amount of raw-fish meal consumed per resident/year was significantly higher in villages that had a strong network of sharing raw-fish food (P<0.001). This study reports for the first time on fish-food sharing among neighbors, proximity to water bodies, frequency of eating raw fish from natural water bodies and low education were key risk factors in C. sinensis infection transmission in northern Vietnam.

The Lawa model: A sustainable, integrated opisthorchiasis control program using the EcoHealth approach in the Lawa Lake region of Thailand

Opisthorchiasis caused by the carcinogenic liver fluke Opisthorchis viverrini is a major foodborne parasitic zoonotic disease in Thailand and neighboring Mekong countries. The infection is associated with several hepatobiliary diseases including cholangiocarcinoma (CCA). The rates of CCA in regions where the parasite is endemic are unprecedented. Extensive research on various aspects of opisthorchiasis has been conducted in recent decades. However, the current status of O. viverrini infection in the country is approaching 85% prevalence in certain endemic areas even after more than 30years of control programs in Thailand. The complex life cycle of the fluke, which involves several hosts/environments, makes it difficult to control by conventional methods. Therefore, a new control strategy using the EcoHealth/One Health approach named the "Lawa model" was introduced into the liver fluke endemic Lawa Lake region in Khon Kaen Province. This program has been underway for over ten years. The program includes treatment with anthelmintic drugs, novel intensive health education methods both in the communities and in schools, ecosystem monitoring and active community participation. We developed the "Liver fluke-free school program" as a part of the Lawa model with successful results. All key stakeholders were empowered to obtain competency in their control activities for the sustainability of the program in the community. Nowadays, the infection rate in the 12 villages surrounding the lake has declined to less than 10% from an average of 60% at the start. The Cyprinid fish species now show less than 1% prevalence of infection compared with a maximum of 70% during the baseline survey. No infected Bithynia snails in the lake were found during recent field studies. Of the lessons learned from the Lawa model, the importance of community participation is one practical and essential component. The key to the success of the project is multi-stakeholder participation with the active local Health Promoting Hospitals and the village health volunteers. The idea of the Lawa model is on the national agenda against liver fluke infection and CCA and is being scaled up to work in larger areas in Thailand. Internationally, the "Lawa model" is one of two programs that are showcased as successful control programs for helminths by the WHO Neglected Zoonotic Diseases (NZD4). Several media outlets have broadcast news reports about the program.

PREVLENCE AND RISK FACTORS FOR OPISTHORCHIS VIVERRINI INFECTION AMONG CATS AND DOGS IN SIX DISTRICTS SURROUNDING THE UBOLRATANA DAM, AN ENDEMIC AREA FOR HUMAN OPISTHORCHIASIS IN NORTHEASTERN THAILAND

Opisthorchis viverrini is a zoonotic liver fluke that causes opisthorchiasis among humans in endemic areas, such as northeastern Thailand. The objective of this study was to determine the prevalence and risk factors for O. viverrini infection among cats and dogs in six districts surrounding Ubolratana Dam. Fecal samples of 1,018 dogs and 249 cats were collected between 2008 and 2013 to examine for O. viverrini infection using a modified formalin-ether concentration technique. The prevalence of O. viverrini infection among cats (77 of 249, 30.92%) was higher than dogs (2 of 1,018, 0.20%). Age and the eating habits of cats were associated with O. viverrini infection. Cats aged >3 years were more likely than those aged <1 year [Odds ratio (OR)=2.96; 95% confidence interval (95% CI): 1.01- 8.35; p = 0.044] of being infected. Cats that consumed raw fish were significantly more likely to be infected than those that consumed other foods (OR=1.82, 95% CI: 1.05-3.16; p = 0.032). Cats had a higher prevalence of O. viverrini infection than dogs and may play an important role in the transmission and maintenance of this disease in the study area.

Efficacious and safe dose of praziquantel for the successful treatment of feline reservoir hosts with opisthorchiasis

Opisthorchiasis caused by Opisthorchis viverrini is a major food-borne zoonosis in Greater Mekong sub-region. Even though campaigns discouraging the consumption of raw fish have been launched to public, the disease still remains highly endemic. The unsuccessful eradication of the disease is probably because of the persistence of the parasite in animal reservoir hosts, particularly felids. Praziquantel (PZQ) is the drug of choice for morbidity control of opisthorchiasis in humans and animals. However, there is no specific study on its dosage regimen for feline opisthorchiasis. Thus, the effective treatment dose of PZQ, as well as its adverse effects, was evaluated in O. viverrini infected cats. Twenty-eight infected male and female cats from the endemic area of Khon Kaen and Maha Sarakham Provinces, Thailand were enrolled in this study. Physical, hematological, blood chemical and urine examinations were analyzed, as indicators of health status, on the day before and 30days after treatment. Intensity of the infections was determined by the formalin-ethyl acetate sedimentation technique. Cats were equally allotted into the low infection group of 14 cats with egg count per gram of feces (EPG) <300 and the high infection group of 14 cats with EPG higher than 300. Cats in each group were equally divided into two subgroups of 7 cats; thus, there were two low infection subgroups (L1 and L2 subgroups) and two high infection subgroups (H1 and H2 subgroups). A single dose of 25mg/kg PZQ was orally administered to each cat in the L1 and H1 subgroups and a single oral dose of 40mg/kg PZQ was administered to the L2 and H2 subgroups. Complete clearance of O. viverrini eggs was found in all cats in the L1, L2 and H2 subgroups; thus, the cure rate (CR) and egg reduction rate (ERR) were 100%. However, partial clearance was observed in two cats with high EPG (1502 and 1518) in the H1 subgroup, which received 25mg/kg PZQ. Regards, CR and ERR for these two animals was 71.4 and 99.5%. No significant difference among the 4 subgroups was seen. Almost all hematological, blood chemical and urinalysis data were within normal ranges, except for the eosinophilia and an increase of alanine aminotransferase (ALT). Hookworm infection seen in all cats would cause eosinophilia. As for drug safety, there was no side effect observed in any cats. In conclusion, this study suggested that 40mg/kg PZQ is a highly effective and safe dosage for the treatment of feline reservoir hosts of human opisthorchiasis.

Decreased risk of cholangiocarcinogenesis following repeated cycles of Opisthorchis viverrini infection-praziquantel treatment: Magnetic Resonance Imaging (MRI) and histopathological study in a hamster model

It has been suggested that repeated infection of Opisthorchis viverrini followed by repeated treatment with praziquantel (PZQ) increases risk of development of cholangiocarcinoma (CCA). Evidence for the prediction has accumulated based on findings of indirect approaches involving molecular changes and epidemiological trends. By contrast, here we directly monitored the impact of repeated liver fluke infection and treatment with PZQ on cholangiocarcinogenesis in a rodent model of human opisthorchiasis, using magnetic resonance imaging (MRI) and histopathology. Twenty five Syrian golden hamsters were assigned to five treatment groups: 1) infection with O. viverrini (OV group), 2) treatment with the carcinogen N-nitrosodimethylamine (NDMA) at 12.5ppm (DMN), 3) O. viverrini infection in tandem with NDMA (OD), 4) O. viverrini infection, NDMA, and treatment with PZQ (ODP), and 5) uninfected, untreated control. The repeated infections were established by intragastric inoculation of 50 metacercariae of O. viverrini to the OV, OD and ODP hamsters at weeks 0, 5 and 10. PZQ at 300mg/kg body weight was given to each hamster of the ODP group on weeks 4, 9 and 13 (four weeks after each infection). Imaging by MRI was undertaken on weeks 5, 10 and 14 (i.e. one week after each PZQ treatment). MRI revealed that the ODP hamsters did not develop CCA, whereas necropsy at week 40 revealed CCA in hamsters of the OD and DMN groups. Findings for histopathology and for proliferating cell nuclear antigen index conformed to the MRI findings. In overview, and notwithstanding that the immune response of individual hosts may play roles in cholangiocarcinogenesis, three cycles of the infection with O. viverrini followed treatment of the infection with PZQ did not increase the risk of bile duct cancer in this hamster model of liver fluke infection-induced CCA.

Cell-based polymerase chain reaction for canine transmissible venereal tumor (CTVT) diagnosis

Canine transmissible venereal tumor (CTVT) is the only naturally contagious tumor that is transmitted during coitus or social behaviors. Based on the tumor’s location, the diagnosis of genital TVT (GTVT) is comparably easier than those in the extragenital area (ETVT) that are more easily incorrectly diagnosed. Fortunately, CTVT cells contain a specific long interspersed nuclear elements (LINE), inserted upstream of the myc gene, allowing a diagnostic polymerase chain reaction (PCR) based detection assay. The objectives of this study were aimed to improve the diagnostic accuracy by applying the diagnostic LINE1-c-myc PCR assay and fine needle aspiration (FNA) collection in direct comparison with standard cytological and histopathological analyses. Seventy-four dogs, comprised of 41 and 31 dogs with tumor masses at their external genitalia and extragenital areas (e.g. skin and nasal cavity), respectively, were included in this study. The signalment of these 65 dogs and clinical history of 20 client-owned dogs were collected. Samples were taken by biopsy for both histopathological examination and FNA for cytological examination and diagnostic PCR. The PCR products from 10 apparently CTVT samples were purified and sequenced. Sixty-one CTVT cases were diagnosed by cytological and histological analyses, but 65 were positive by the PCR assay. Overall, the PCR assay improved the accuracy of diagnostic CTVT results, especially for the more difficult ETVT tumors. Moreover, this PCR-based approach can facilitate the decision as to discontinue chemotherapy by discrimination between residual tumor cell masses and fibrotic tissue.

Application of Immunophenotyping and Heteroduplex Polymerase Chain Reaction (hPARR) for Diagnosis of Canine Lymphomas

BACKGROUND

Canine malignant lymphoma is classified into B- or T-cell origin, as in the human case. Due to differences in prognosis, a suitable method needs to be developed for lineage identification.

AIMS

To determine the accuracy of immunophenotypic and molecular information between three methods: immunocytochemistry (ICC), immunohistochemistry (IHC) and heteroduplex polymerase chain reaction for antigen receptor rearrangements (hPARR) in spontaneous canine lymphomas.

MATERIALS AND METHODS

Peripheral blood, fine needle aspiration and tissue biopsies from enlarged peripheral lymph nodes prior to treatment of 28 multicentric lymphoma patients were collected. Cytopathology and histopathology were examined and classified using the updated Kiel and WHO classifications, respectively. Anti-Pax5 and anti-CD3 antibodies as B- and T-cell markers were applied for immunophenotyping by ICC and IHC. Neoplastic lymphocytes from lymph node and white blood cell pellets from peripheral blood were evaluated by hPARR.

RESULTS

In this study, low grade B-cell lymphoma accounted for 25% (7/28), high grade B-cell lymphoma for 64.3% (18/28) and high grade T-cell lymphoma for 10.7% (3/28). According to the WHO classification, 50% of all cases were classified as diffuse large B-cell lymphoma. In addition, ICC showed concordant results with IHC; all B-cell lymphomas showed Pax5+/CD3, and all T-cell lymphomas exhibited Pax5-/CD3+. In contrast to hPARR, 12 B-cell lymphomas featured the IgH gene; seven presented the TCRγ gene; five cases showed both IgH and TCRγ genes, and one case were indeterminate. Three T-cell lymphomas showed the TCRγ gene. The percentage agreement between hPARR and ICC/IHC was 60%.

CONCLUSIONS

Immunophenotyping should not rely on a single method. ICC or IHC with hPARR should be used concurrently for immunophenotypic diagnosis in canine lymphomas.

Immunodiagnosis of opisthorchiasis using parasite cathepsin F

Opisthorchis viverrini, a food-borne trematode parasite endemic in the lower Mekong countries, is conventionally diagnosed by stool examination. However, parasitological stool-based diagnosis can be unreliable in light infections. The goal of this study was to develop the immunodiagnosis of opisthorchiasis using cathepsin F cysteine protease of O. viverrini in both indirect and sandwich ELISA assays. A recombinant O. viverrini cathepsin F (rOv-CF) of 40 kDa was expressed in E. coli strain BL21 (DE3), affinity purified, and deployed in ELISA assays. Human sera from 272 cases were investigated by indirect rOv-CF-based ELISA. Positive antibody response to rOv-CF was found in 137 out of 272 cases (50.37 %) using a cutoff OD (0.400) determined by ROC analysis. In comparison to parasitological stool examined for fluke eggs, the gold standard, the rOv-CF indirect ELISA showed a sensitivity and specificity of 62.1 and 84.05 %, respectively. Serum antibody levels correlated well with egg counts per gram feces (EPG) (P < 0.001). In addition, chicken IgY antibody raised against rOv-CF was tested in a sandwich ELISA for detection of coproantigen in the feces of experimentally infected hamsters. The sandwich ELISA using this chicken IgY in combination with rabbit antibody to O. viverrini somatic antigens showed sensitivity and specificity of 93.3 and 78.57 %, respectively. Together, these findings indicated the potential of rOv-CF for diagnosis of opisthorchiasis, including for uses with chicken IgY for detection of coproantigens of O. viverrini.

Toward integrated opisthorchiasis control in northeast Thailand: the Lawa project

Human liver fluke, Opisthorchis viverrini, a food-borne trematode is a significant public health problem in Southeast Asia, particularly in Thailand. Despite a long history of control programmes in Thailand and a nationwide reduction, O. viverrini infection prevalence remains high in the northeastern provinces. Therefore, a new strategy for controlling the liver fluke infection using the EcoHealth/One Health approach was introduced into the Lawa Lake area in Khon Kaen province where the liver fluke is endemic. A programme has been carried using anthelminthic treatment, novel intensive health education methods both in the communities and in schools, ecosystem monitoring and active community participation. As a result, the infection rate in the more than 10 villages surrounding the lake has declined to approximate one third of the average of 50% as estimated by a baseline survey. Strikingly, the Cyprinoid fish species in the lake, which are the intermediate host, now showed less than 1% prevalence compared to a maximum of 70% at baseline. This liver fluke control programme, named "Lawa model," is now recognised nationally and internationally, and being expanding to other parts of Thailand and neighbouring Mekong countries. Challenges to O. viverrini disease control, and lessons learned in developing an integrative control programme using a community-based, ecosystem approach, and scaling-up regionally based on Lawa as a model are described.

A portrait of the transcriptome of the neglected trematode, Fasciola gigantica--biological and biotechnological implications

Fasciola gigantica (Digenea) is an important foodborne trematode that causes liver fluke disease (fascioliasis) in mammals, including ungulates and humans, mainly in tropical climatic zones of the world. Despite its socioeconomic impact, almost nothing is known about the molecular biology of this parasite, its interplay with its hosts, and the pathogenesis of fascioliasis. Modern genomic technologies now provide unique opportunities to rapidly tackle these exciting areas. The present study reports the first transcriptome representing the adult stage of F. gigantica (of bovid origin), defined using a massively parallel sequencing-coupled bioinformatic approach. From >20 million raw sequence reads, >30,000 contiguous sequences were assembled, of which most were novel. Relative levels of transcription were determined for individual molecules, which were also characterized (at the inferred amino acid level) based on homology, gene ontology, and/or pathway mapping. Comparisons of the transcriptome of F. gigantica with those of other trematodes, including F. hepatica, revealed similarities in transcription for molecules inferred to have key roles in parasite-host interactions. Overall, the present dataset should provide a solid foundation for future fundamental genomic, proteomic, and metabolomic explorations of F. gigantica, as well as a basis for applied outcomes such as the development of novel methods of intervention against this neglected parasite.

Fasciola gigantica (Digenea) is a socioeconomically important liver fluke of humans and other mammals. It is the predominant cause of fascioliasis in the tropics and has a serious impact on the lives of tens of millions of people and other animals; yet, very little is known about this parasite and its relationship with its hosts at the molecular level. Here, advanced sequencing and bioinformatic technologies were employed to explore the genes transcribed in the adult stage of F. gigantica. From >20 million raw reads, >30,000 contiguous sequences were assembled. Relative levels of transcription were estimated; and molecules were characterized based on homology, gene ontology, and/or pathway mapping. Comparisons of the transcriptome of F. gigantica with those of other trematodes, including F. hepatica, showed similarities in transcription for molecules predicted to play roles in parasite-host interactions. The findings of the present study provide a foundation for a wide range of fundamental molecular studies of this neglected parasite, as well as research focused on developing new methods for the treatment, diagnosis, and control of fascioliasis.

Mutations of KRAS and TP53 in a minor proportion of Opisthorchis viverrini-associated cholangiocarcinomas in a hamster model

BACKGROUND/AIMS

KRAS oncogene and TP53 tumor suppressor gene have been known as common genes involving in many cancers including cholangiocarcinoma (CCC). Activation of these genes could lead to uncontrolled proliferation and cancer ultimately. The aim of this study was to investigate mutation of KRAS exon 1 and TP53 exon 5-8 in Opisthorchis viverrini (OV)-induced cholangiocarcinoma (CCA) in a hamster model.

METHODS

Twenty-seven CCAs were obtained from Syrian golden hamsters induced by OV infection and N-nitrosodimethylnitrosamine (N-NDDM) administration. The tumor tissues were processed for histopathology. Genomic DNA extracted from paraffin sections by microdissection was amplified for KRAS exon 1 and TP53 exon 5-8 mutations by PCR-direct sequencing.

RESULTS

Histopathologically, the tumors were classified into tubular (81.5%, 22/27), papillary (3.7%, 1/27), mucinous (3.7%, 1/27) and mixed types (11.1%, 3/27). Of the 27 CCAs, PCR-direct sequencing of KRAS showed G[see text]A transition at codon 37 exon 1 in one CCA sample (3.70%). Point mutations of p53 exon 6 (G[see text]C transversion at codon 119 and 218 and A[see text]C transversion at codon 217) were found in 3 CCA samples (11.1%).

CONCLUSIONS

The results suggest that mutation of TP53 particularly at exon 6 may be involved in cholangiocarcinogenesis and a novel mutation of KRAS exon 1 was firstly reported in OV-induced hamster CCA.