Clonorchiasis

Clonorchiasis is an infection with the liver fluke Clonorchis sinensis, a trematode that inhabits the bile ducts ^[2]. The provided sources characterize it as a neglected parasitic zoonosis and place it within a broader group of liver-fluke diseases that includes opisthorchiasis ^[1][3][4][5]. It is described as having a complex life cycle involving humans, animal reservoirs, and two kinds of intermediate hosts ^[1].

The source material indicates that clonorchiasis is primarily associated with liver and biliary disease rather than an acute syndromic description ^[2]. Chronic infection is linked to hepatobiliary complications, with cholangiocarcinoma identified as the most important complication in the reviewed literature ^[1][2]. The snippets do not provide source-backed detail on symptom timing, severity staging, or complication frequency beyond this chronic hepatobiliary association ^[1][2].

Clonorchiasis is described as occurring mainly in East Asia, where it reflects regional social-ecological systems and a long-standing cultural practice of consuming raw freshwater fish ^[2]. A 2024 review states that clonorchiasis and related liver-fluke infections impose a considerable public-health burden in eastern Asia, southeastern Asia, and eastern Europe, respectively, but the precise distribution and exact number of infected people remain unknown for clonorchiasis itself ^[1][2]. The literature notes that biological, cultural, ecological, economic, and social factors all contribute to transmission, and that mapping the current distribution remains a pressing research need ^[1].

Transmission is supported by the life cycle description involving humans, animal reservoirs, and two kinds of intermediate hosts ^[1]. The available sources specifically link clonorchiasis in East Asia to the cultural habit of consuming raw freshwater fish, indicating an exposure pathway through fish consumption ^[2]. Further source-backed detail on persistence in the environment or additional exposure mechanisms is not yet available ^[1][2].

The source material identifies people in endemic East Asian settings, especially those with raw freshwater fish consumption, as a key exposure group ^[2]. Because the life cycle involves humans and animal reservoirs, populations in close contact with the relevant ecological settings may be at risk, but the snippets do not provide a more detailed source-backed risk stratification ^[1].

The main control approach described in the sources is preventive chemotherapy with praziquantel, usually combined with behavior change through information, education, and communication, together with environmental control or environmental management ^[1][2]. The literature also mentions integrated control strategies and novel approaches under development, including fish vaccine and biological control ^[1]. The sources do not provide a detailed prevention schedule or operational guidance beyond these broad control measures ^[1][2].

For surveillance purposes, clonorchiasis should be read as a zoonotic hepatobiliary infection whose burden is concentrated in defined endemic regions and whose chronic complications may be substantial even when the exact number of infections is uncertain ^[1][2]. Stool microscopy is described as widely used in epidemiologic surveys and for individual diagnosis, while immunologic methods are used for screening and molecular methods for species differentiation in reference laboratories ^[1]. The available sources therefore support surveillance that combines burden mapping, exposure-context interpretation, and attention to chronic biliary outcomes ^[1][2].

1. 1 Qian M-B et al. Clonorchiasis and opisthorchiasis: epidemiology, transmission, clinical features, morbidity, diagnosis, treatment, and control. Clin Microbiol Rev. 2024 Mar 14. PMID: 38169283. doi: 10.1128/cmr.00009-23. PubMed: https://pubmed.ncbi.nlm.nih.gov/38169283/
2. 2 Qian MB et al. Clonorchiasis. Lancet. 2016 Feb 20. PMID: 26299184. doi: 10.1016/S0140-6736(15)60313-0. PubMed: https://pubmed.ncbi.nlm.nih.gov/26299184/
3. 3 Clonorchiasis. Neglected Parasitic Zoonoses of Helminth Origin. 2025. doi: 10.1201/9781032697499-11. DOI: https://doi.org/10.1201/9781032697499-11
4. 4 Clonorchiasis. The Cambridge World History of Human Disease. 1993. doi: 10.1017/chol9780521332866.091. DOI: https://doi.org/10.1017/chol9780521332866.091
5. 5 Clonorchiasis. Encyclopedia of Parasitology. None. doi: 10.1007/978-3-540-48996-2_643. DOI: https://doi.org/10.1007/978-3-540-48996-2_643
6. 6 Chai JY et al. Albendazole and Mebendazole as Anti-Parasitic and Anti-Cancer Agents: an Update. Korean J Parasitol. 2021 Jun. PMID: 34218593. doi: 10.3347/kjp.2021.59.3.189. PubMed: https://pubmed.ncbi.nlm.nih.gov/34218593/

ICD-10

B66.1

ICD-11

1F89.0

Total cases

48K

Peak month

2026-05

Coverage

1 reporting countries · 2026-01-01 → 2026-05-01