High Reinfection Rate after Preventive Chemotherapy for Fishborne Zoonotic Trematodes in Vietnam

Lier, Tore; Trung, Dung; Johansen, Maria Vang; Nguyen, Thi Hop; Dalsgaard, Anders; Asfeldt, Anne Mette

doi:10.1371/journal.pntd.0002958

Cited by 17 publications

(12 citation statements)

References 31 publications

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“…The association between frequent PZQ treatment and re-infection has also been shown in other studies of the liver fluke [ 18 , 20 ]. This pattern of infection and re-infection after treatment has also been found in Vietnam [ 26 ]. Another study in Laos found no significant association between past PZQ treatment and infection [ 27 ], however, this study only measured whether the medication had ever been taken, not the frequency of previous treatments.…”

Section: Discussionsupporting

confidence: 74%

Repeated praziquantel treatment and Opisthorchis viverrini infection: a population-based cross-sectional study in northeast Thailand

et al. 2019

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BackgroundOpisthorchis viverrini infection is highly prevalent in northeast Thailand. This liver fluke is classified as a carcinogen due to its causal links with cholangiocarcinoma (CCA) development. Although treatment with praziquantel (PZQ) effectively cures O. viverrini infection, the prevalence remains high due to the traditional consumption of raw fish. Therefore, re-infection is common in the endemic community, leading to severe hepato-biliary morbidities including the fatal CCA. In this study, we evaluate the association between the frequency of previous PZQ treatment and current O. viverrini infections among Thai adults living in the endemic area of northeast Thailand.MethodsThis study includes all participants who were screened for O. viverrini infection in the Cholangiocarcinoma Screening and Care Program (CASCAP), northeast Thailand. History of PZQ treatment was recorded using a health questionnaire. O. viverrini infections were diagnosed using urine antigen detection. Associations between PZQ and O. viverrini were determined by adjusted odds ratio (aOR) and 95% confidence interval (CI) using multiple logistic regression.ResultsAmong participants, 27.7% had previously been treated once with PZQ, 8.2% twice, 2.8% three times, and 3.5% more than three times. Current O. viverrini prevalence was 17% (n = 524). Compared with participants who never used PZQ, the aOR for infection among those who used the drug once was 1.09 (95% CI: 0.88–1.37), twice was 1.19 (95% CI: 0.85–1.68), three times was 1.28 (95% CI: 0.74–2.21), and more than three times was 1.86 (95% CI: 1.18–2.93; P = 0.007).ConclusionsThe population with a frequent history of PZQ use and still continued raw fish consumption showed high levels of repeated reinfection with O. viverrini. They were infected, treated and re-infected repeatedly. These findings suggest that certain participants continue raw fish consumption even after previous infection. This is a particular problem in highly endemic areas for O. viverrini and increases the risk of CCA.Electronic supplementary materialThe online version of this article (10.1186/s40249-019-0529-5) contains supplementary material, which is available to authorized users.

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Section: Discussionsupporting

confidence: 74%

Repeated praziquantel treatment and Opisthorchis viverrini infection: a population-based cross-sectional study in northeast Thailand

et al. 2019

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“…As individuals previous infected with C. sinensis show no apparent protective immunity after recovery from treatment [27] and re-infection is common in endemic areas [9,28], we proposed a deterministic Susceptible-Infected-Susceptible (SIS) model to describe the transmission of C. sinensis among human-snail-fish populations, where infected human recovered from infection will instantly return to the susceptible state. According to different frequencies of raw-fish consumption, we classified the human population into four groups, that is seldom, moderately (less than 5 times per year), often (5-10 times per year) and very often (more than 10 times per year) eating of raw fish.…”

Section: The Basic Modelmentioning

confidence: 99%

“…Based on a typical setting of C. sinensis transmission (Fusha Town), we simulated scenarios according to strategies recommended by WHO, the Chinese government and the government of Guangdong Province, with intervention duration of five years. On one hand, the WHO strategy, mainly focusing on chemotherapy of whole population, could decrease the human prevalence rapidly but were not sustainable (Fig 4), even with an extension of intervention duration to 30 years (S4 Fig), which may due to the high reinfection of the disease [9,28]. On the other hand, strategies recommended by the Chinese government and the government of Guangdong Province could reach their setting goals within 5 years of intervention (Fig 4).…”

Section: Three Recommended Strategiesmentioning

confidence: 99%

Assessment of control strategies against Clonorchis sinensis infection based on a multi-group dynamic transmission model

et al. 2020

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Clonorchiasis is one of the most important food-borne trematodiases affecting millions of people. Strategies were recommended by different organizations and control programmes were implemented but mostly in short-time periods. It's important to assess the long-term benefits and sustainability of possible control strategies on morbidity control of the disease. We developed a multi-group transmission model to describe the dynamics of C. sinensis transmission among different groups of people with different raw-fish-consumption behaviors, based on which, a full model with interventions was proposed and three common control measures (i.e., preventive chemotherapy, information, education, and communication (IEC) and environmental modification) and their possible combinations were considered. Under a typical setting of C. sinensis transmission, we simulated interventions according to different strategies and with a series of values of intervention parameters. We found that combinations of measures were much beneficial than those singly applied; higher coverages of measures had better effects; and strategies targeted on whole population performed better than that on at-risk population with raw-fish-consumption behaviors. The strategy recommended by the government of Guangdong Province, China shows good and sustainable effects, under which, the infection control (with human prevalence <5%) could be achieved within 7.84 years (95% CI: 5.78-12.16 years) in our study setting (with original observed prevalence 33.67%). Several sustainable strategies were provided, which could lead to infection control within 10 years. This study makes the effort to quantitatively assess the long-term effects of possible control strategies against C. sinensis infection under a typical transmission setting, with application of a multi-group dynamic transmission model. The proposed model is easily facilitated with other transmission settings and the simulation outputs provide useful information to support the decision-making of control strategies on clonorchiasis.

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“…As NTDs have garnered much-needed attention in recent years, many global partnerships have been formed and several pharmaceutical companies have pledged free drugs to combat NTDs worldwide [ 4 ]. Preventive chemotherapy has been shown to be effective in reducing the prevalence and morbidity of NTDs but reinfection with the parasite is also very common among endemic populations [ 5 – 7 ].…”

Section: Main Textmentioning

confidence: 99%

“…More often than not, interventions were treatment-oriented and solely aimed at alleviating the current complication that were plaguing the target population. For instance, although preventive chemotherapy by means of mass drug administration (MDA) could bring down the prevalence, the reinfection rate is also high [ 5 – 7 ]. This intervention through MDA alone brings the issue of sustainability into question.…”

Section: Main Textmentioning

confidence: 99%

The potential of positive deviance approach for the sustainable control of neglected tropical diseases

et al. 2016

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Neglected tropical diseases (NTDs) have gained much attention in recent years due to the support from various agencies. However, the main approach to combat NTDs has been to cure rather than to prevent. As many NTD infections are closely linked with human behaviors such as hygienic practices and tradition, behavior change is also very crucial to prevent relapse or reinfection. Therefore, we would like to suggest a potential new approach—the positive deviance approach—to tackle NTDs by focusing on the preventive phase. What makes this approach unique is that the solution comes from the affected population themselves and not from the expert outsiders. Preventive chemotherapy that relies on outside aid has serious sustainability issues as reinfection is also high after the aid program has ended. Learning from the success story in Vietnam on preventing childhood malnutrition, the positive deviance approach could end the spread of NTDs once and for all by making full use of the available local solutions.

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High Reinfection Rate after Preventive Chemotherapy for Fishborne Zoonotic Trematodes in Vietnam

Cited by 17 publications

References 31 publications

Repeated praziquantel treatment and Opisthorchis viverrini infection: a population-based cross-sectional study in northeast Thailand

Repeated praziquantel treatment and Opisthorchis viverrini infection: a population-based cross-sectional study in northeast Thailand

Assessment of control strategies against Clonorchis sinensis infection based on a multi-group dynamic transmission model

The potential of positive deviance approach for the sustainable control of neglected tropical diseases

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