Interspecies Phylogenetic Analysis of Clonorchis sinensis in High-incidence Areas of Hunan Province, China.

OBJECTIVE: This study aims to investigate the infection of Clonorchis sinensis ( C. sinensis) in high-incidence areas of Hunan Province, China. The phylogenetic analysis of the C. sinensis species in the highly infected areas was carried out. METHOD: Infection of the definitive human host and intermediate fish host by C. sinensis was investigated, and the mitochondrial genes cox1 and Nad1were used as genetic markers for phylogenetic analysis. RESULTS: In 2016-2020, the average population infection rate of Hunan was 1.38%, while in Tongdao County the rate was up to 26.90%, and the highest fish infection rate was detected in Qiyang County (99.44% in the dorsal fin of crucian carp). High genetic sequence similarity was observed in the samples from Qiyang and Lengshuitan which exhibited high homology with those from Guangdong and Gansu, whereas the parasitic species from Tongdao was highly homologous with those located in high-latitude areas. Moreover, no significant difference was found in the gene sequence of the parasitic species in definitive hosts dogs and cats. CONCLUSION: The systematically study of C. sinensis infection in the high-incidence areas will contribute greatly to the prevention and effectively controlling the spread of Clonorchis sinensis in Hunan Province The endemic of C. sinensis infection in Hunan Province is the result of co-action of local and foreign parasite species.

Epidemiology and determinants of clonorchiasis in school children in southeastern China.

Clonorchiasis is an important food-borne parasitic disease in China because of the popularity in ingesting raw freshwater fish. To explore the epidemiology and determinants of clonorchiasis in children, a cross-sectional survey was implemented in two middle schools in Qiyang county, Hunan province, in southeastern China. Questionnaire survey and fecal examination were implemented. Questionnaires were fed back by 627 students, while stool samples were collected from 557 students, out of which 545 ones also provided questionnaire information. The percentage of students ingesting raw freshwater fish was 40.5% (254/627), while the prevalence with Clonorchis sinensis infection was 18.9% (105/557). Such factors contributed significantly to the students' practice in eating raw freshwater fish including boys, fathers' eating raw freshwater fish, mothers' eating raw freshwater fish, and preparation of raw freshwater fish at home, with an adjusted odds ratio of 1.9 (95% confidence intervals (95% CI): 1.3-2.8), 3.9 (95% CI: 2.3-6.5), 3.0 (95% CI: 1.8-4.8) and 2.8 (95% CI: 1.8-4.5), correspondingly. Ingestion of raw freshwater fish, fathers' eating raw freshwater fish and preparation of raw freshwater fish at home were risk factors of C. sinensis infection in students, and the adjusted odds ratio was 3.2 (95% CI: 1.9-5.5), 2.1 (95% CI: 1.1-3.9) and 1.8 (95% CI: 1.0-3.2), respectively. Thus, clonorchiasis was endemic in the surveyed schools due to the ingestion of raw freshwater fish, which is influenced by family environment. Education should be implemented in schools to promote behavioral change of eating raw freshwater fish.

Improving diagnostic performance of the Kato-Katz method for Clonorchis sinensis infection through multiple samples.

BACKGROUND: Clonorchiasis is caused by eating of raw or undercooked freshwater fish containing the larvae of Clonorchis sinensis; the Kato-Katz method is widely applied in diagnosis. The improvement of repeated Kato-Katz smears from multiple stool samples has been well illuminated in many helminths other than C. sinensis. METHODS: A cross-sectional investigation was implemented to capture the epidemiology and risk factors of clonorchiasis among middle school students in Qiyang county, China. Students with complete data of six Kato-Katz thick smears from two stool samples were included in this analysis. Data on the habits of eating raw freshwater fish were also collected and compared. RESULTS: Altogether, 397 students had complete information of six smears, out of which 394 reported the information on eating habits. According to the 'gold' standard by six smears, 77 students (19.4%) were detected with C. sinensis. However, only 45 (11.3%) were detected using a single smear, with an underestimation of 41.6% compared to the 'gold' standard. However, the geometric mean of eggs per gram of feces in detected cases was 126.4 in a single smear, overestimated by 105.2% compared to 61.6 by the 'gold' standard. The linear relationship between prevalence and infection intensity of detected cases based on different smears was significantly negative. The habits of eating raw freshwater fish in the false negative cases was similar to those in the detected cases, but these two groups had significantly higher levels for habits of eating raw freshwater fish than negative individuals. CONCLUSIONS: In low endemicity situations, underestimation of C. sinensis infection could not be avoided based on a limited number of Kato-Katz smears. Thus, repeated smears from at least two stool samples should be considered when an individual eats raw freshwater fish, drug efficacy is evaluated or elimination of C. sinensis is verified. Additionally, when logistics are insufficient for multiple samples to be taken for diagnosis for survey and surveillance in the areas or populations of low endemicity, prevalence accuracy needs to be corrected.

Efficacy and safety of praziquantel, tribendimidine and mebendazole in patients with co-infection of Clonorchis sinensis and other helminths.

BACKGROUND: Both tribendimidine and mebendazole are broad-spectrum drugs for anti-intestinal nematodes. We aim to assess the efficacy and safety of tribendimidine and mebendazole in patients with co-infection of Clonorchis sinensis and other helminths. METHOD: We performed a randomized open-label trial in Qiyang, People's Republic of China. Eligible participants were randomly assigned to one of four groups: (i) a single dose of 400 mg tribendimidine, (ii) 200 mg tribendimidine twice daily, (iii) 75 mg/kg praziquantel divided in four doses within 2 days, and (iv) a single dose of 400 mg mebendazole. Cure rates and egg reduction rates were assessed, and adverse events were monitored after treatments. Uncured patients accepted the second treatment with the same drugs after the first treatment. RESULTS: 156 patients were eligible for the study. Results from the first treatment showed that the cure rates of single-dose tribendimidine and praziquantel against C. sinensis were 50% and 56.8%, respectively; the single-dose tribendimidine achieved the cure rate of 77.8% in the treatment for hookworm, which was significantly higher than that of praziquantel; Low cure rates were obtained in the treatment of single-dose tribendimidine against Ascaris lumbricoides and Trichuris trichiura (28.6% and 23.1%). Results of the second treatment illustrated the cure rates of tribendimidine and praziquantel against C. sinensis were 78.1% and 75%, respectively. Most adverse events were mild and transient. Adverse events caused by tribendimidine were significantly less than praziquantel. CONCLUSION: Single-dose tribendimidine showed similar efficacy against C. sinensis as praziquantel with less adverse events, and achieved significantly higher cure rate in the treatment for hookworm than those of praziquantel and mebendazole. Low cure rates, which were still higher than other drugs, were obtained in the treatment of single-dose tribendimidine against Ascaris lumbricoides and Trichuris trichiura. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN55086560.

[Malaria situation in Hunan Province during 2011-2013].

Malaria data in 2011-2013 were collected and statistically analyzed using Microsoft Excel 2003 software. A total of 501 malaria cases were reported, and the annual incidence was 0.2510/100,000, 0.2486/100,000, and 0.3223/100,000, in 2011, 2012, and 2013, respectively, with an average of 0.2740/100,000 in Hunan Province. All these cases were imported and mainly reported from Changsha (44.3%, 222/501), Shaoyang (16.6%, 83/501), Huaihua (8.4%, 42/501), and Yiyang (8.0%, 40/501). 97.0% (486/501) of the cases were laboratory confirmed cases, while the other 3.0% (15/501) were clinically diagnosed. Among those lab confirmed, 41.3% (207/501) were vivax malaria cases, 47.9% (240/501) falciparum malaria cases, 1.4% (7/501) ovale malaria cases, 0.8% (4/501) malariae cases, 6.6% (33/501) mixed infection, and 2.0% (10/501) were unclassified cases. Most cases (202/501) occurred among persons aged 40-49 years. These patients were mainly farmers, workers, migrant workers, and cadres. 47.7% (239/501) were from Africa and 50.1% (251/501) from Southeast Asia.