An investigation of Human Clonorchiasis prevalence in an Endemic County in Guangxi Zhuang Autonomous Region, China, 2016

Epidemiology and risk factors of Clonorchis sinensis infection in the mountainous areas of Longsheng County, Guangxi: insights from automated machine learning

Clonorchis sinensis (C. sinensis) is mainly prevalent in Northeast and South China, with Guangxi being the most severely affected region. This study aimed to evaluate the prevalence and identify the risk factors of C. sinensis infection in Longsheng County, a mountainous area in northern Guangxi. In 2023, a comprehensive study was conducted in Longsheng County, utilizing longstanding inhabitants as study participants. Questionnaires were employed to gather data on fish consumption, awareness of C. sinensis, and residential coordinates, while fecal examinations were utilized to identify C. sinensis infection. Important risk factors for the C. sinensis infection were identified through the development of individual infection risk models using automated machine learning techniques. A total of 740 fecal samples were collected, revealing an overall C. sinensis infection rate of 69.59%. The gradient boosting machine (GBM) was the most accurate predictor with an area under the precision-recall Curve (AUPRC) of 0.997. The model identified years of raw fresh fish consumption, frequency of raw fresh fish consumption, elevation, and water distance as the top four predictors of C. sinensis infection risk. In conclusion, our study has revealed a high infection rate of C. sinensis in the mountainous areas of Longsheng County, with adults, men, and farmers particularly susceptible to both high incidence and infection severity. We developed a high-performance predictive model for individual C. sinensis infection within the county, identifying the key risk factors for local infections. These findings offer valuable guidance for the control and prevention of clonorchiasis.

The association between Clonorchis sinensis seropositivity and hepatocellular carcinoma in an endemic area: a study in Guangxi, China

BACKGROUND

Chronic infection with Clonorchis sinensis (C.sinensis) has been associated swith the development of intrahepatic cholangiocarcinoma (ICC); however, the relationship between C.sinensis and hepatocellular carcinoma (HCC) remains uncertain.

METHODS

This study examined 120 patients with liver cancer in the clonorchiasis endemic area of Hengzhou, Guangxi, China. The type of cancer, the differentiation grade according to Edmondson Steiner's classification, and the pathological characteristics of HCC were determined through postoperative tissue biopsy. C.sinensis infection was detected by measuring serum specific IgG antibody, and hepatitis B virus (HBV) infection was determined by detecting serum HBsAg and HBV DNA in HCC tissues. The C.sinensis infection rates in control groups were drawn from the local general population based on previous surveys. The association between C.sinensis infection and HCC was analyzed by comparing the differences in C.sinensis infection rates between the two groups.

RESULTS

Of the patients evaluated, 98 (81.7%) had HCC, 21 (17.5%) had ICC, and 1 (0.8%) had comorbidity of HCC/ICC. Among the HCC patients, 24 (24.5%) were solely infected with HBV, 71 (72.4%) were C. sinensis seropositive, and 3 (3.1%) showed no evidence of infection. C. sinensis seropositive rates in HCC patients are much higher than in general outpatient and non-liver cancer inpatients (χ2 = 141.92, p < 0.001), as well as in the local residents (χ2 = 82.61/21.38, p < 0.001). There were no significant differences in the pathological type, differentiation grade, and lesion composition between the tumor associated with C.sinensis/HBV mono- and co-infection (p > 0.05). Among the patients with C.sinensis-related HCC, 8 (8.2%) were solely C.sinensis seropositive, while 63 (64.3%) were co-infected with HBV. Infection with C. sinensis and HBV has a significant impact on the pathological types of liver cancer (χ2 = 22.86, p < 0.001).

CONCLUSIONS

These findings indicate that HCC still accounts for the majority of liver cancer in this region. In addition to being most commonly related with HBV infection, HCC may also be related to C. sinensis infection. Co-infection of C. sinensis and HBV may enhance the development of HCC in this area.

CLINICAL TRIAL

Not applicable.

Prevalence estimates of Opisthorchis viverrini and Clonorchis sinensis infection in the Greater Mekong subregion: a systematic review and meta-analysis

BACKGROUND

Opisthorchiasis and clonorchiasis, caused by Opisthorchis viverrini and Clonorchis sinensis, respectively, are significant yet neglected foodborne trematodiases in the Great Mekong Subregion (GMS). Despite the reporting of the prevalence of these human liver flukes in the region over the past decades, there has been a lack of a comprehensive and systematic consolidation of this data. Therefore, we aimed to conduct a thorough systematic review and meta-analysis to synthesize and analyze time-trend prevalence estimates of both O. viverrini and C. sinensis across the GMS for the past 30 years.

METHODS

This study undertakes a systematic review using a comprehensive search for published articles in PubMed, EMBASE, Scopus, Cochrane and Thai Journal Online databases until early 2023. The pooled prevalence of O. viverrini and C. sinensis infection was analyzed through a random-effects meta-analysis, with meta-regression analysis used to quantify associations with study characteristics. Sub-group analysis was conducted, whenever comparison data were available, to assess the risk of O. viverrini and C. sinensis infection in each GMS country. Heterogeneity among studies was assessed using the Q statistic and quantified by using the I 2 Index.

RESULTS

From a total of 2997 articles, 155 articles comprising 218 datasets and 751,108 participants were included for review. The GMS prevalence of O. viverrini was 21.11% [45,083/260,237; 95% confidence interval (CI): 17.74-24.47%]. Pooled prevalence estimates were highly observed in Laos (34.06%, 95% CI: 26.85-41.26%), followed by Thailand (18.19%, 95% CI: 13.86-22.51%), and Cambodia (10.48%, 95% CI: 5.52-15.45%). Myanmar and Vietnam had limited data sources for calculation. Clonorchis sinensis infection in GMS was 25.33% (95% CI: 18.32-32.34%), with Guangxi, China, exhibiting the highest prevalence rates at 26.89% (95% CI: 18.34-35.43%), while Vietnam had a prevalence rate of 20.30% (95% CI: 9.13-31.47%). O. viverrini prevalence decreased significantly over time, whereas C. sinensis infection appeared to be stable consistently over time in both China and Vietnam.

CONCLUSIONS

This comprehensive study, drawing from the largest datasets to date, offers an in-depth systematic prevalence review of human liver flukes in the Greater Mekong Subregion. It underscores the imperative for systematic surveillance, data collection, and the implementation of intervention and control measures for these infectious diseases of poverty.

Effectiveness of health education in improving knowledge, attitude and practice related to foodborne zoonotic trematodes in Vietnam, with a particular focus on Clonorchis sinensis

OBJECTIVE

Foodborne zoonotic trematodes (FZT), which infect the liver, lungs and intestines of humans, are an emerging public health concern in tropical countries including Vietnam. In northern Vietnam, Clonorchis sinensis is recognised as the most important species of the FZT. Up to now, small-scale studies conducted in the country have indicated that health education could improve participants' knowledge and practices related to clonorchiasis, however strong evidence is still lacking. We conducted an intervention trial between 2020 and 2021 in four communes in Yen Bai and Thanh Hoa province, aiming to evaluate the impact of an extended educational package on knowledge, attitude and practices related to clonorchiasis, as well as on knowledge on the large liver fluke and minute intestinal flukes.

METHODS

To this end, baseline and post-intervention questionnaires were conducted. Generalised estimating equations models were run to analyse the impact of the intervention on knowledge, attitudes and practices over time in the intervention versus control group. Finally, 172 people in the intervention group and 162 in the control group were included for analysis.

RESULTS

Results demonstrated that the intervention significantly improved clonorchiasis knowledge, attitudes and practices, with higher odds for a correct knowledge response (odds ratio (OR) = 2.80, 95% confidence interval (CI) = 1.84-4.27, p-value < 0.001), increased average mean attitude score (mean = 0.363, 95%CI = 0.182-0.544, p-value < 0.001), and a reduced odds of consuming raw fish (OR = 0.15, 95%CI = 0.06-0.40, p = 0.002) in the intervention group compared to the control group post-intervention versus baseline. Additionally, participants in the intervention group exhibited enhanced basic knowledge of the large liver fluke and minute intestinal flukes post-intervention.

CONCLUSIONS

These findings demonstrate the potential of health education programs in preventing clonorchiasis in endemic areas, emphasising the importance of continued health education as a critical component of integrated control programs for clonorchiasis.

Epidemiological characterization of Clonorchis sinensis infection in humans and freshwater fish in Guangxi, China

Background

Clonorchiasis is a widespread yet neglected foodborne disease with over 85% of all cases found in China. Guangxi province, located in southeastern China, ranks among the highest endemic provinces. We explore the epidemiological status and determinants of Clonorchis sinensis (C. sinensis) infection in humans and freshwater fish in Guangxi, China.

Methods

Data on C. sinensis infection in humans from January 2008 to December 2017were extracted from the China Information System for Disease Control and Prevention. An active surveillance of C. sinensis infection in fish was conducted in 2016–2017. County level data including potential environmental, social-economical and behavioral determinants was also collected. Univariate and multivariate logistic regression models were used to explore the determinants of C. sinensis infection in humans and fish. Simple and multiple zero-inflated Poisson regression models were fit to assess the associated factors of clonorchiasis in humans at the county level.

Results

Totally, 4526 C. sinensis cases were reported between 2008 and 2017, with an annual prevalencerate of 0.96/100,000 persons. Of 101 counties in Guangxi, 97 reported at least 1 case. Among 2,098 fish samples, 203 (9.7%) from 70 counties contained C. sinensis. The rate was higher in small fish including Pseudorasbora parva (45.3%), Misgurnus anguillicaudatus (41.2%), Hemicculter leuciclus (34.5%), unclassified small fishes (30.9%), Cyprinidae (20.0%), Cirrhinus molitorella (16.4%), Carassius auratus (13.6%) and Cyprinus carpio (13.3%), while it was lower in fish species that are usually used in preparing raw fish dishes including Ctenopharyngodon idellus (3.6%), Spinibarbus denticulatus (3.7%), Monopterus albus (6.4%), Cyprinus carpio (4.4%), Oreochromis mossambicus (3.3%) and Spualiobarbus Curriculus (6.6%). The C. sinensis infection in fish was only associated with fish species. The estimated human clonorchiasis prevalence at the county level was positively associated with raw fish consumption habits and certain rivers.

Conclusions

Clonorchiasis is highly prevalent in both humans and freshwater fish in Guangxi. Environmental, social-economic and behavioral determinants contribute to the high prevalence as well as the significant differential distribution by county. Regular surveillance should be implemented for clonorchiasis to demonstrate the change in epidemiology and burden, which will benefit the design of interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07244-2.

Current status of human liver fluke infections in the Greater Mekong Subregion

The Greater Mekong Subregion (GMS) is a trans-national region of the Mekong River basin in Southeast Asia comprising Cambodia, the People's Republic of China (specifically Yunnan Province and Guangxi Zhuang Autonomous Region), Lao People's Democratic Republic (Lao PDR), Myanmar, Thailand, and Vietnam home to more than 340 million people or almost 4.5% of the global population. Human liver fluke infections caused by Opisthorchis viverrini and Clonorchis sinensis have been major public health problems in this region for decades. Opisthorchiasis caused by O. viverrini is prevalent in Thailand, Lao PDR, Cambodia and central-southern Vietnam with more than 12 million people infected. Clonorchiasis caused by C. sinensis is endemic in northern Vietnam and Guangxi with estimated 3.5 -5 million infected. The infections can cause several liver and biliary diseases such as cholangitis, periductal fibrosis, gallstones, and cholangiocarcinoma (CCA), a fatal bile duct cancer. Key determinants of the geographical distribution differences of the two liver fluke species are snail species and geographic barriers. Main risk behaviour of the infections is the culture of eating raw fish "the raw attitude" of people in the GMS, especially the Tai/Dai/Thai/Laos ethnic groups, the major population in the GMS. Over the past 20 years, there is a big change in prevalence of the infections. Opisthorchiasis has long been endemic, particularly in northern and northeastern Thailand and Lao PDR with over 8-10 million cases estimated. However, after several rounds of national campaign against opisthorchiasis using integrated control approach in Thailand over the past three decades, the prevalence of O. viverrini infection has reduced from over 15% in 1996 to 2.2% in 2019. High prevalence of O. viverrini infection continues in Lao PDR and central Vietnam. Emerging high prevalence, up to a maximum of 47.5%, has been noted in Cambodia during the past 10 years possibly due to more studies being conducted rather than increasing prevalence. O. viverrini infection has now also been reported in Lower Myanmar in recent years. Clonorchiasis has been known in northern Vietnam and southern China for a long time. Several surveys have reported infections in Guangxi in the last 10 years, and until now liver fluke infected cases have not been reported in Yunnan. Overall, nowadays, there is a shift in high risk areas for GMS liver fluke infection from northeastern Thailand to Lao PDR, Cambodia, Vietnam, Myanmar, and Guangxi P.R. China. Urgent systematic disease mapping and integrated liver fluke control using One Health approaches should be implemented nationwide in GMS countries.