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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. [ABSTRACT FROM AUTHOR]

Background: To understand Clonorchis sinensis reinfection and the determinants of reinfection in endemic areas is important in establishment of control measures.Methods: A prospective cohort study was implemented in Hengxian County, Guangxi, China. Individuals with C. sinensis infection were completely treated, and those cured were enrolled as study subjects and followed up for 3, 6, and 12 months. The reinfection frequency and incidence were calculated, and a multivariable Cox proportional hazard model was constructed to capture reinfection determinants.Results: Among 635 enrolled subjects, 436 (68.7%) completed follow-up. Of these, 177 (40.6%) were reinfected; 133 (75.1%) were reinfected once, 41 (23.2%) twice, and 3 (1.7%) three times. The incidence of reinfection was 64.0 per 100 person-years. Men (adjusted hazard ratio [aHR], 1.67; 95% confidence interval [CI], 1.14-2.44), those with underlying diseases (aHR, 1.41; 95% CI, 1.02-1.95), and those with moderate- or heavy-intensity infections (aHR, 1.45; 95% CI, 1.14-1.85) had increasing reinfection probabilities.Conclusions: C. sinensis reinfection is high in endemic areas. Men and high-intensity infection are important determinants of reinfection. Repeated chemotherapy is necessary to control reinfection and its associated morbidities, especially in high-risk individuals. In addition, behavioral education is advised to decrease overall reinfection in endemic areas. [ABSTRACT FROM AUTHOR]

High-intensity clonorchiasis infection is associated with serious outcomes, including cancer. Understanding the infection intensity of Clonorchis sinensis and its risk factors in local endemic regions could facilitate effective control measures. In a county located in a highly endemic area in Guangxi Province, P. R. China, local residents were randomly enrolled in the study; helminth egg examinations were performed with the Kato-Katz method, and the intensity of infection was identified as mild, moderate or heavy. Knowledge, attitudes, and high-risk behaviours were investigated among those infected with Clonorchis sinensis. A total of 2521 local residents participated in this study, and the Clonorchis sinensis-positive proportion was 28.9% (728 persons). Among the infected persons, the percentages of mild, moderate and heavy infections were 66.2%, 28.4% and 5.4%, respectively. Males experienced a higher proportion of moderate and heavy infections (37.5%) than females (18.1%) (p<0.05). The highest infection proportion among the different levels of infection intensity was identified among persons aged 30–59 years (15.7% for moderate and heavy infections). Among the 509 persons who reported eating raw fish, 302 persons (59.3%) had eaten raw fresh fish for more than 10 years, and 131 (25.7%) persons ate raw fish ≥12 times a year. Multivariate logistic regression revealed that eating raw fish 12–50 times in the last year (adjusted odds ratio [aOR] = 1.74, 95%CI: 1.09–2.80) and eating raw fish >50 times in the last year (aOR = 2.89, 95%CI: 1.20–7.50) were risk factors for high-intensity infections (moderate and heavy). The overall infection proportion was high in the study area, with a large group of residents experiencing high-intensity infections. High frequency of raw fish consumption was associated with high-intensity infections. Intervention strategies targeting people with a high frequency of raw fish consumption should be implemented to reduce the probability of severe consequences. Author summary: Clonorchiasis, which is caused by Clonorchis sinensis, is one of the most endemic parasite diseases in China. Humans get infected by eating the raw or undercooked freshwater fish that contain the nymphal stage of Clonorchis sinensis. There are about 15 million cases globally with 85% of those in China. Two major endemic areas were found in China, including Guangdong and Guangxi Province in the south part of China, and Heilongjiang, Jilin and Liaoning Province in the north part of China. In this study, by analysing the dataset from one county in Guangxi Province, we found the overall proportion of infection was high, with one third of infection persons were classified as high intensity of infection. Male and persons aged 30–59 years developed higher burden of infection. Besides, persons who eat high frequency of raw fish developed high intensity of infection. Health education on the high risk populations should be strengthened to change the diet custom. Other measure such as examination of freshwater fish in the market should also be implemented. [ABSTRACT FROM AUTHOR]

Background: Triatomines are natural vectors of Chagas disease and are mainly prevalent in the Americas. In China, previous data from decades ago showed that there were two species of triatomine bugs, Triatoma rubrofasciata and T. sinica. However, the distribution, genetic characteristics and public health implications of triatomines in China are still relatively unknown. In order to gain knowledge on the distribution, genetic characteristics and public health implications of the triatomines in Guangxi, China, an entomological-epidemiological study and genetic research was conducted. Methods: Different methods were used to elucidate the distribution of triatomines in Guangxi including consultations with county-level Center for Disease Prevention and Control staff and village doctors, the distribution of educational material on triatomines though the internet and social media apps such as Wechat and QQ, and conducting manual inspections and light trapping to collect triatomines. The morphological characteristics of the collected triatomines were identified under light microscopy. The mitochondrial 16S rRNA, cytochrome b (cytb) genes and nuclear 28S rRNA gene were amplified, sequenced and used in phylogenetic analyses. Results: A total of 305 triatomines were captured from 54 different sites in 13 cities in Guangxi. All collected bugs were identified as T. rubrofasciata based on morphology. Most triatomine collection sites were around or inside houses. Four triatomines bite cases were observed during the investigation indicating that triatomine bites are common, the bites can cause serious anaphylaxis and skin papules and urticaria, suggesting a systemic skin response. The 16S rRNA, 28S rRNA and cytb sequence analyses of T. rubrofasciata from Guangxi and other countries showed that T. rubrofasciata sequences from different regions exhibit a high similarity, with no geographical differences. The phylogenetic tree based on the 16S rRNA and cytb genes showed that T. rubrofasciata sequences from different regions and continents were in the same cluster, indicating no differentiation among different geographical populations. Conclusions: Our study showed that T. rubrofasciata is widely distributed in Guangxi and that people are commonly bitten by this insect in some regions. This highlights the need to enhance surveillance for and control of T. rubrofasciata and to strengthen the monitoring of imported Trypanosoma cruzi in China. The 16S rRNA, 28S rRNA and cytb sequence analyses of T. rubrofasciata from different regions and continents suggested that T. rubrofasciata populations exhibit high similarity, and the clustering in the phylogenetic analyses indicates that T. rubrofasciata has a close ancestor originating in the Americas. [ABSTRACT FROM AUTHOR]

Background: The resistance of Plasmodium falciparum to artemisinin has been identified in Asia and some parts of Africa. The drug resistance of P. falciparum will be an obstacle to the successful elimination of malaria by 2025. Whole-genome sequencing of the artemisinin-resistant parasite line revealed mutations on the k13 gene associated with drug resistance in P. falciparum. To understand the artemisinin resistance of the imported P. falciparum cases from Africa, the mutations in the k13 gene in parasites from imported malaria cases in Guangxi Province were detected and the treatment efficiency of artesunate monotherapy was observed. Methods: DNA was extracted from 319 blood samples from migrant workers with P. falciparum infection who returned to their hometown in Guangxi Province from Africa between 2014 and 2017. The k13-propeller gene was amplified by nested PCR, and sequencing, gene mutation frequency and geographic difference of imported P. falciparum cases were analysed by comparison with the wild-type strain. Of 319 patients, 158 were P. falciparum-infected and were treated with intravenous injection of artesunate and were observed, including the time of asexual stage clearance and the dose of artesunate used. Results: Of the 319 P. falciparum samples, 12 samples had the k13-propeller mutation, and 11 point mutations were detected; 5 were non-synonymous mutations (T474I, A481T, A578S, V603E, G665S) and were not associated with artemisinin resistance. The clinical treatment observation showed that the median (IQR) dose of artesunate for peripheral blood parasite asexual stage clearance was 407.55 (360–510) mg, and the D3 parasite clearance rate was 70.25%, including the five k13-propeller mutations of P. falciparum. After 7 days of treatment, 98.73% of cases were cleared. Two cases were treated with artemisinin for 8 days with a 960-mg dose to completely clear the asexual parasite, but they did not have a mutation in the k13 gene. Conclusions: Five mutations of the k13-propeller gene in 319 P. falciparum samples from patients returning from Africa were identified. The frequency of the k13-propeller mutants was low, and the mutations were not strongly associated with artemisinin resistance. The median (IQR) dose of artesunate monotherapy in actual clinical treatment to remove asexual parasite stages was 407.55 (360–510) mg, equivalent to D3–D4. Some P. falciparum cases without a k13-propeller mutation showed obvious delayed clearance of the parasite from peripheral blood. Trial registration The diagnosis of malaria and the treatment of malaria-infected patients are the routine work of Centres for Disease Control and Prevention. Information on the patients was conveyed with the patient's approval, and the research aim, methods, risks and benefits of the study were explained in detail to the patients [ABSTRACT FROM AUTHOR]

Background: Echinococcosis has led to considerable social and economic losses in China, particularly in the endemic communities of the eastern Tibetan Plateau. In China, human cases of Echinococcus granulosus (sensu stricto), E. canadensis and E. multilocularis infections have been described, but no E. ortleppi (G5) infections in humans or animals have been reported. Results: A case of E. ortleppi infection in a human from Guangxi, which is a non-endemic echinococcosis area in China, is described. A 17 × 12 × 20 cm (diameter) cyst was observed in the liver of the patient, and Echinococcus larvae were collected from the cyst. A morphological examination indicated that the larvae were E. ortleppi, and amplification and analysis of the nicotinamide adenine dinucleotide hydrogenase dehydrogenase subunit 1 (nad1) and cytochrome c oxidase subunit 1 (cox1) genes showed that the larvae had 99–100% homology with the corresponding E. ortleppi sequences on GenBank. Conclusions: To our knowledge, this report describes the first identification of a human E. ortleppi infection in China. Our data broaden the geographical distribution of this rarely reported species of Echinococcus. [ABSTRACT FROM AUTHOR]

• Opisthorchiasis and clonorchiasis are major public health problems affected over 15 million in the GMS. • Opisthorchis viverrini is endemic in Lower Mekong Basin while Clonorchis sinensis is endemic in Guangxi and northern Vietnam. • Snail intermediate hosts and geographical barrier are key determinants in distribution difference. • Emerging human liver fluke infections occur in Cambodia, Myanmar, and Guangxi over the past 20 years. • Systematic exploring of the disease burdens and integrated control using One Health approach are warranted. 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. [ABSTRACT FROM AUTHOR]