Genetic Differentiation of Opisthorchis-Like Eggs in Northern Thailand Using Stool Specimens Under National Strategic Plan to Control Liver Fluke Infection and Cholangiocarcinoma

Buathong, Saiwasan; Phaiphilai, Kateitsaray; Ruang-areerate, Toon; Sitthichot, Naruemon; Thita, Thanyapit; Mungthin, Mathirut; Suwannahitatorn, Picha

doi:10.4269/ajtmh.20-0231

Cited by 11 publications

(6 citation statements)

References 44 publications

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“…were more abundant than O. viverrini in the central part of Lao PDR [32]. In northern Thailand, using molecular diagnostics the occurrence of MIF was recently found to be 3.8-fold higher than O. viverrini [33].…”

Section: Discussionmentioning

confidence: 95%

Performances of Mini Parasep SF stool concentrator kit , Kato-Katz and formalin-ethyl acetate concentration methods for diagnosis of opisthorchiasis among residents in an endemic community in northeast Thailand

Kopolrat

Singthong

Khuntikeo

et al. 2022

Preprint

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Background Control and elimination of the liver fluke (Opisthorchis viverrini) is a primary preventive strategy against cholangiocarcinoma in Southeast Asia. A sensitive parasitological diagnostic method is required to facilitate such a surveillance and control program. In this study, we evaluated the performance of Mini Parasep SF stool concentrator kit (stool kit) in comparison with Kato-Katz (KK) and the quantitative formalin-ethyl acetate concentration technique (FECT) for detection of O. viverrini and coexisted parasitic infections. Methods A cross-sectional survey of parasitic infection of residents age <15 years old in a community in Kalasin province, northeast Thailand was conducted in 2018. Fecal samples were collected and screened by KK method and a subset of samples was examined by the stool kit and FECT methods. The results were analyzed for prevalence of parasitic infections and diagnostic performances of methods for qualitative and quantitative detection of helminthiasis. Results The initial survey of parasitic infection determined by the KK method (n=567) showed the prevalence of O. viverrini was 32.63%, followed by Taenia 2.65%, echinostomes 1.76%, hookworms 1.41%, Trichuris trichiura 0.53%, and Strongyloides stercoralis 0.53%. Within a subset of samples tested with multiple diagnostics (n=150), the detection rates of O. viverrini by the stool kit, FECT, and KK methods were 27.3%, 30.7%, and 28.7%, respectively. The diagnostic sensitivity for opisthorchiasis were similar for FECT (75.4%) and KK (70.5%) and was lower for the stool kit (67.2%, p<0.05). For other parasitic infections, FECT and stool kit performed better than KK methods particularly in detecting minute intestinal fluke (MIF), S. stercoralis, and coinfections. The intensity of O. viverrini infection (fecal egg counts) by the stool kit had significant positive correlations with KK as well as FECT (p<0.05). Conclusions As the stool kit is simple to use and showed a comparable performance to FECT, it may serve as an alternative method of fecal examination for screening of helminthiasis including opisthorchiasis.

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Section: Discussionmentioning

confidence: 95%

Performances of Mini Parasep SF stool concentrator kit , Kato-Katz and formalin-ethyl acetate concentration methods for diagnosis of opisthorchiasis among residents in an endemic community in northeast Thailand

Kopolrat

Singthong

Khuntikeo

et al. 2022

Preprint

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“…We explore the impact of imperfect diagnostic specificity on the observed prevalence under simplistic scenarios shown in figure 2 f ; in reality, we expect specificity for O. viverrini to covary with the endemicity of minute intestinal flukes. The increased use of molecular diagnostics enables the species of parasite egg to be identified [66], and recent improvements to O. viverrini antigen tests also provides a method to discriminate cases [67,68].…”

Section: Discussionmentioning

confidence: 99%

Diagnosis of helminths depends on worm fecundity and the distribution of parasites within hosts

et al. 2023

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Helminth transmission and morbidity are dependent on the number of mature parasites within a host; however, observing adult worms is impossible for many natural infections. An outstanding challenge is therefore relating routine diagnostics, such as faecal egg counts, to the underlying worm burden. This relationship is complicated by density-dependent fecundity (egg output per worm reduces due to crowding at high burdens) and the skewed distribution of parasites (majority of helminths aggregated in a small fraction of hosts). We address these questions for the carcinogenic liver fluke Opisthorchis viverrini , which infects approximately 10 million people across Southeast Asia, by analysing five epidemiological surveys ( n = 641) where adult flukes were recovered. Using a mechanistic model, we show that parasite fecundity varies between populations, with surveys from Thailand and Laos demonstrating distinct patterns of egg output and density-dependence. As the probability of observing faecal eggs increases with the number of mature parasites within a host, we quantify diagnostic sensitivity as a function of the worm burden and find that greater than 50% of cases are misdiagnosed as false negative in communities close to elimination. Finally, we demonstrate that the relationship between observed prevalence from routine diagnostics and true prevalence is nonlinear and strongly influenced by parasite aggregation.

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“…In areas of mixed infections with O. viverrini and MIF ( H. taichui , for example), molecular testing of the fecal eggs would be advantageous. Buathong et al (2020) 42 reported the usefulness of PCR and PCR-restriction fragment length polymorphism (PCR–RFLP) analysis targeting internal transcribed spacer 2 (ITS2) gene in differentially diagnosing O. viverrini and H. taichui infections in northern Thailand.…”

Section: Discussionmentioning

confidence: 99%

High endemicity of Opisthorchis viverrini infection among people in northern Cambodia confirmed by adult worm expulsion

Jung

Hong

Chang

et al. 2023

Sci Rep

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Opisthorchis viverrini infection is an emerging disease in Cambodia, especially in central and southeastern areas. However, its status in northern areas bordering Lao PDR has been relatively unknown. The present study was performed to investigate the status of O. viverrini infection among people in Preah Vihear and Stung Treng provinces through fecal examination to detect eggs and recovery of adult flukes from some of the egg-positive cases. Fecal examinations were performed on a total of 1101 people from 10 villages in the 2 provinces using the Kato-Katz thick smear technique. For recovery of adult flukes and other helminth parasites 10 volunteers positive for eggs of Opisthorchis viverrini and/or minute intestinal flukes (Ov/MIF), in Kampong Sangkae village, Preah Vihear province, were administered a single oral dose of 40 mg/kg praziquantel plus 5–10 mg/kg of pyrantel pamoate and purged with 40–50 g magnesium salts. Adult trematodes, together with nematodes and cestodes expelled in diarrheic stools were collected under a stereomicroscope or with the naked eye. The proportion of egg-positive cases for overall liver and intestinal helminths was high but not notably different between the 2 provinces, 65.5% in Preah Vihear versus 64.7% in Stung Treng. The average proportion of Ov/MIF egg-positive cases was 59.8%. A total of 315 adult specimens of O. viverrini were recovered from the 10 volunteers (4–98 specimens per individual; mean, 32). A smaller number of Haplorchis taichui adults, an intestinal fluke, were found mixed-infected in 7 (103 specimens in total; 1–31 per individual; mean, 15) of the 10 volunteers. Adult specimens of hookworms, Enterobius vermicularis, Trichostrongylus sp., and a Taenia tapeworm strobila were recovered in some cases. Based on the results, it has been confirmed that the surveyed areas in Preah Vihear and Stung Treng provinces, Cambodia, are highly endemic areas of O. viverrini infection with a low-grade mixed infection with H. taichui.

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Genetic Differentiation of Opisthorchis-Like Eggs in Northern Thailand Using Stool Specimens Under National Strategic Plan to Control Liver Fluke Infection and Cholangiocarcinoma

Cited by 11 publications

References 44 publications

Performances of Mini Parasep SF stool concentrator kit , Kato-Katz and formalin-ethyl acetate concentration methods for diagnosis of opisthorchiasis among residents in an endemic community in northeast Thailand

Performances of Mini Parasep SF stool concentrator kit , Kato-Katz and formalin-ethyl acetate concentration methods for diagnosis of opisthorchiasis among residents in an endemic community in northeast Thailand

Diagnosis of helminths depends on worm fecundity and the distribution of parasites within hosts

High endemicity of Opisthorchis viverrini infection among people in northern Cambodia confirmed by adult worm expulsion

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