Is Opisthorchis viverrini Emerging in Cambodia?

Khieu, Virak; Fürst, Thomas; Miyamoto, Kazuko; Yong, Tai Soon; Chai, Jong Yil; Huy, Rekol; Muth, Sinuon; Odermatt, Peter

doi:10.1016/bs.apar.2019.02.002

Cited by 24 publications

(37 citation statements)

References 67 publications

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“…However, the estimates should be taken cautious due to large district-wide variances and a relatively small number of surveys. Indeed, O. viverrini infection was underreported in Cambodia (Khieu et al, 2019), and further point-referenced survey data are recommended for more confirmative results.…”

Section: Discussionmentioning

confidence: 93%

Model-based spatial-temporal mapping of opisthorchiasis in endemic countries of Southeast Asia

Zhao

Feng

Doanh

et al. 2021

eLife

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Opisthorchiasis is an overlooked danger to Southeast Asia. High-resolution disease risk maps are critical but have not been available for Southeast Asia. Georeferenced disease data and potential influencing factor data were collected through a systematic review of literatures and open-access databases, respectively. Bayesian spatial-temporal joint models were developed to analyze both point- and area-level disease data, within a logit regression in combination of potential influencing factors and spatial-temporal random effects. The model-based risk mapping identified areas of low, moderate, and high prevalence across the study region. Even though the overall population-adjusted estimated prevalence presented a trend down, a total of 12.39 million (95% Bayesian credible intervals [BCI]: 10.10–15.06) people were estimated to be infected with O. viverrini in 2018 in four major endemic countries (i.e., Thailand, Laos, Cambodia, and Vietnam), highlighting the public health importance of the disease in the study region. The high-resolution risk maps provide valuable information for spatial targeting of opisthorchiasis control interventions.

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Section: Discussionmentioning

confidence: 93%

Model-based spatial-temporal mapping of opisthorchiasis in endemic countries of Southeast Asia

Zhao

Feng

Doanh

et al. 2021

eLife

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“…In 2009, the national prevalence of O. viverrini in Thailand was reported as 8.7% based on a modified KK [7]. Opisthorchis viverrini is a food-borne trematode fluke which is transmitted by [21]. In addition, due to the consumption of Koi and other raw fish dishes, cholangiocarcinoma, which is induced by O. viverrini, is a major health problem [2,7,11,22].…”

Section: Discussionmentioning

confidence: 99%

“…Opisthorchis viverrini is a food-borne trematode fluke which is transmitted by consumption of raw or undercooked fish. Koi, a dish of raw, spiced fish, is a popular dish in Thailand and Lao, providing a ready means of infection with this parasite; indeed, infection with O. viverrini is relatively common in Thailand, Lao, Myanmar and Cambodia [ 21 ]. In addition, due to the consumption of Koi and other raw fish dishes, cholangiocarcinoma, which is induced by O. viverrini , is a major health problem [ 2 , 7 , 11 , 22 ].…”

Section: Discussionmentioning

confidence: 99%

Clinical helminthiases in Thailand border regions show elevated prevalence levels using qPCR diagnostics combined with traditional microscopic methods

et al. 2020

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Background: Under-regulated national borders in Southeast Asia represent potential regions for enhanced parasitic helminth transmission and present barriers to helminthiasis disease control. Methods: Three Thailand border regions close to Myanmar, Laos and Cambodia were surveyed for clinical parasitic helminth disease. In-field microscopy was performed on stools from 567 individuals. Sub-samples were transported to Bangkok for molecular analysis comprising three multiplex qPCR assays. Results: The overall helminth infection prevalence was 17.99% as assessed by Kato-Katz and 24.51% by qPCR. The combined prevalence of the two methods was 28.57%; the most predominant species detected were Opisthorchis viverrini (18.34%), hookworm (6.88%; Ancylostoma spp. and Necator americanus), Ascaris lumbricoides (2.29%) and Trichuris trichiura (1.76%). Conclusions: These data demonstrate the value of molecular diagnostics for determining more precise prevalence levels of helminthiases in Southeast Asia. Availability of such accurate prevalence information will help guide future public health initiatives and highlights the need for more rigorous surveillance and timely intervention in these regions.

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“…Unpicking which factors were most influential in driving long-term trends would therefore be of value. In Laos and Cambodia, by contrast, the available evidence suggests that transmission of O. viverrini is either stable or increasing [16,19].…”

Section: Modelling For Parasitologistsmentioning

confidence: 94%

Towards Evidence-based Control of Opisthorchis viverrini

Crellen

Sithithaworn

Pitaksakulrat

et al. 2021

Trends in Parasitology

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Transmission of the carcinogenic liver fluke Opisthorchis viverrini is ongoing across Southeast Asia. Endemic countries within the region are in different stages of achieving control. However, evidence on which interventions are the most effective for reducing parasite transmission, and the resulting liver cancer, is currently lacking. Quantitative modelling can be used to evaluate different control measures against O. viverrini and assist the design of clinical trials. In this article we evaluate the epidemiological parameters that underpin models of O. viverrini and the data necessary for their estimation, with the aim of developing evidence-based strategies for parasite control at a national or regional level. Assessing InterventionsControl initiatives against the liver fluke O. viverrini are driven by two related aims. Firstly, to reduce transmission of the parasite, leading to its elimination (see Glossary). Secondly, to halt the progression of O. viverrini-induced liver pathology, and thus prevent new cases of cholangiocarcinoma [1]. In endemic regions, definitive hosts become infected through consumption of raw or insufficiently cooked freshwater fish encysted with metacercariae and perpetuate the life cycle by defecating into water sources containing snails of the Bithynia genus. Programmes to control O. viverrini therefore have a number of interventions available to them, including health education to promote safe eating habits; case diagnosis and anthelmintic treatment; improvements to sanitation; and food safety controls [2]. Parasite-induced liver pathology can be tackled with ultrasound screening to detect periductal fibrosis, an early warning sign of cholangiocarcinoma; and operative surgery to improve survival rates [3]. With such a variety of tools on offer, policy makers, international health organisations, and affected communities are entitled to ask: what works? Which measures are most effective at interrupting transmission of the parasite and reducing mortality in a cost-effective, sustainable manner?The traditional method for answering this question is through randomised controlled trials, which are the gold standard for assessing interventions [4]. Such trials, however, are costly, take many years, and require substantial manpower and expertise. It is also unethical to conduct trials in contexts where public health initiatives are ongoing and would have to be withdrawn for participants allocated into the control arm of a trial. An alternative approach is to use quantitative models to make predictions on the effectiveness of different control strategies. These models take myriad forms, can be parameterised from routinely collected field data, and provide considerable insight for a fraction of the cost of a trial. Different types of models that can capture macroparasite dynamics are summarised in Box 1.When the need to conduct a clinical trial is unavoidable, for example on novel therapeutics or diagnostics, dynamic simulations can provide powerful insights into trial design, power HighlightsH...

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Is Opisthorchis viverrini Emerging in Cambodia?

Cited by 24 publications

References 67 publications

Model-based spatial-temporal mapping of opisthorchiasis in endemic countries of Southeast Asia

Model-based spatial-temporal mapping of opisthorchiasis in endemic countries of Southeast Asia

Clinical helminthiases in Thailand border regions show elevated prevalence levels using qPCR diagnostics combined with traditional microscopic methods

Towards Evidence-based Control of Opisthorchis viverrini

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