Review calls for better One Health models of liver fluke spread: full analysis

A new review in Science in One Health takes stock of how scientists have modeled transmission of the liver flukes Clonorchis sinensis, Opisthorchis viverrini, and O. felineus, and concludes that the next generation of models needs to better reflect real-world transmission. Published online March 24, 2026, the paper is positioned as the first comprehensive review of mechanistic models for these infections, which remain important foodborne parasitic diseases in Asia and are linked to substantial chronic hepatobiliary disease, including cholangiocarcinoma. (sciencedirect.com)

That conclusion builds on a long-standing problem: liver fluke transmission is biologically complex, and control programs have often had to act with incomplete evidence about which interventions matter most in a given setting. WHO says these foodborne trematode infections require cross-sector collaboration at the human-animal-environment interface. Their life cycle involves freshwater snails as the first intermediate host, freshwater fish as the second host for Clonorchis and Opisthorchis, and mammals as definitive hosts. In endemic areas, dogs, cats, and other fish-eating mammals can serve as reservoirs, which is one reason simple, human-only models may miss important drivers of persistence. (who.int)

According to the review abstract and article summary, the authors searched PubMed, Web of Science, Korea Med, Cochrane, CNKI, and Wanfang Data for studies published through May 14, 2025. Their main message is that mechanistic models have been useful for summarizing transmission assumptions and testing intervention scenarios, but the literature still has notable blind spots. Among the limitations they highlight are insufficient attention to spatial heterogeneity, oversimplified treatment of animal reservoirs, and the need for more data-driven One Health frameworks that integrate human, animal, and environmental transmission parameters. They also point to climate-linked factors and agent-based modeling as priority directions for future work. (sciencedirect.com)

Older modeling work helps explain why this matters. A 2020 PLOS Neglected Tropical Diseases study on C. sinensis used a multi-group dynamic transmission model to test combinations of chemotherapy, information and education efforts, and environmental modification, and found combined strategies outperformed single interventions. That paper also emphasized that raw-fish consumption behavior varies across populations and changes transmission risk, suggesting that models become more useful when they capture heterogeneity rather than assuming a uniform population. The new review appears to extend that critique across the broader liver fluke modeling literature. (journals.plos.org)

Direct outside commentary on the new review was limited in readily available sources, but the broader expert consensus lines up with the paper’s direction. WHO and CDC materials both frame these infections as complex, foodborne zoonoses with long-lasting infections and a cancer link, while WHO guidance stresses preventive chemotherapy, health education, and environmental contamination reduction as core control levers. In that context, the review’s call for models that better connect animal reservoirs, environmental contamination, and human behavior looks less like a theoretical exercise and more like an effort to make intervention planning more realistic. (who.int)

Why it matters: For veterinary professionals, especially those working in One Health, public health, aquatic food systems, or travel- and import-linked parasitology, this review reinforces that companion animals and other fish-eating mammals may be more than background variables in endemic settings. If models undercount reservoir hosts, they may overestimate what human treatment alone can achieve. That has implications for surveillance design, risk communication to pet parents about feeding raw freshwater fish, and collaboration with human health and environmental authorities in endemic regions. It also underscores a broader veterinary point: parasite control programs are stronger when they account for animal behavior, local ecology, and the production environment, not just drug coverage. (who.int)

What to watch: The next step is likely more granular modeling, potentially including spatially explicit or agent-based approaches, plus better field data on reservoir hosts and environmental contamination. If that work emerges, it could sharpen how endemic countries target praziquantel campaigns, sanitation measures, fish-farm interventions, and animal-focused risk reduction. (sciencedirect.com)