Objective To clone and express the valuable Clonorchis sinensis antigen molecules which can be applied to the diagnosis of clonorchiasis. Methods Based on the sequences (Genbank) No. AF271091 (CysA) and No.AF093242 (CysB), primers were designed to amplify the two C. sinensis cysteine proteinase genes and expressed in E.cloi. The expressed proteins were purified by affinity chromatography and then tested for their immunological characters.Results The two genes were successfully cloned and expressed. Western blot showed that CysB had strong reaction with clonorchiasis sera and very weak reaction with schistosomiasis sera, while CysA showed no reactivity with the probed sera. Immunohistochemistry showed that both proteins were mainly located in adult worm intestines and the intrauterine eggs.Conclusions The results suggested that, of the two expressed C. sinensis proteins, CysB had good antigenic reactivity against sera from patients. It is a potential candidate of diagnostic antigens for clonorchiasis.

Objective To analyze the epidemic status of principal human parasites, so as to provide scientific evidence for making prevention countermeasures for Guangdong Province in the future. Methods In 2015, a survey was performed according to the scheme of "The 3rd National Survey of Principal Human Parasites"as well as the incidence of parasites disease in Guangdong Province,the residents at 48 investiation sites in counties were surveyed. The survey of the soil-transmitted nematodes (Ascariasis, Ancylostoma, Trichuris trichiura and Enterobius vermicularis) and intestinal protozoa were performed based on the ecological regions and stratified by economic and geographic situation.The survey of food borne Clonorchis sinensis was performed along with the soil-transmitted nematodes in rural areas, and it was performed by the sample method of random cluster in cities and towns.The residents in each investigation site as the object, the ovum of the soil-transmitted nematodes, Clonorchis sinensis and other helminths were examed by the modified Kato-Katz method, test tube filter paper was used to identify Hookwormspecies, and the intestinal protozoa was checked by direct smear method. The transparent tape anal swabs method for children aged 3 - 6 years to check Enterobius vermicularis. Results Totally 12 401 residents of 48 survey sites from 22 counties were surveyed, and the total infection rate of intestinal parasites was 8.29%(1 028/12 401). The infection rate of soil-transmitted nematodes was 3.39% (420/12 401),in which the infection rate of Ascariasis, Ancylostoma, Trichuris trichiura and Enterobius vermicularis were 0.52% (64/12 401), 1.89%(234/12 401),0.46%(57/12 401),and 0.52%(65/12 401),respectively.The infection rate of Clonorchis sinensis was 4.90%(608/12 401). Nine hundred and sixty-seven children were tested for eggs of Enterobius vermicularis with the infection rate of 12.41% (120/967). The number of hook larva culture was 153, among them, 140 were hookworm larvae of America and no duodenal hookworm larvae and other nematode species were found.Totally 9 309 residents were tested for intestinal protozoa infection,and the infection rate was 0.31%(29/9 309). Conclusion In Guangdong Province, the infection rate of soil-transmitted nematodes is decreasing while the infection rate of Clonorchis sinensis is still high, and the control work of parasites still should be strengthened especially for food borne parasitic diseases.

Objective To observe the effects of recombinant protein ferritin heavy chain of Clonorchis sinensis (CsFHC) on human hepatic stellate cell line LX-2. Methods LX-2 cells were cultured in vitro by the cell culture method . Cell proliferation/toxicity detection kit (CCK-8) was used to detect the cell proliferation activity of LX-2 cells stimulated with CsFHC recombinant protein [0 (control), 1, 2, 5, 10, 20 nmol/L] at 48 h and 72 h, respectively, and the effect of CsFHC recombinant protein on cell cycle was analyzed by flow cytometry; a semi quantitative RT-PCR was used to detect the mRNA expression of type I collagen (Collagen Ⅰ), type Ⅲ collagen (Collagen Ⅲ) and α smooth muscle actin (Αsma). Results The effects of CsFHC on proliferation of LX-2 cells (48 h: 0.987 ± 0.042, 1.315 ± 0.105, 1.298 ± 0.078, 1.432 ± 0.089, 1.781 ± 0.040, 1.581 ± 0.056; 72 h:1.050 ± 0.030, 1.503 ± 0.111, 1.671 ± 0.102, 1.769 ± 0.123, 1.927 ± 0.067, 1.492 ± 0.081) between groups were significantly different statistically (F = 1892.133, 534.136, P<0.05). The quiescent stage/DNA synthesis (G0/G1 ) cells in 1, 2, 5, 10, and 20 nmol/L CsFHC recombinant protein groups (74.93 ± 4.05, 75.87 ± 4.16, 76.73 ± 5.03, 78.57 ± 5.51, 74.90 ± 3.61) were significantly higher than that of control group (54.90 ± 3.61, P<0.05);the synthesis phase (S) + DNA synthesis late/mitotic (G2/M) cells (22.24 ± 3.06, 24.13 ± 2.00, 18.54 ± 1.53, 18.71 ± 1.53 and 21.17 ± 3.06) were lower than that of control group (33.26 ± 2.65,P < 0.05). In control and 1, 2, 5, 10, 20 nmol/L CsFHC recombinant protein groups, the differences of Mrna expression levels of Collagen Ⅰ, Collagen Ⅲ and α SMA were statistically significant (48 h:F=81.419, 14.417, 70.456;72 h:F=79.224, 50.461, 41.872, P<0.05). Conclusion The CsFHC recombinant protein can stimulate the proliferation and activation of LX-2 cells in vitro, the CsFHC involved in the process of hepatic fibrosis induced by Clonorchis sinensis.

Objective To investigate the epidemiological characteristics and spatial distribution characteristics of Clonorchis sinensis human infections in Guangdong Province from 2016 to 2022, so as to provide insights into formulation of the clonorchiasis control measures in the province. Methods Xinhui District of Jiangmen City, Longmen County of Huizhou City and Wengyuan County of Shaoguan City in Guangdong Province were selected as fixed surveillance sites for human clonorchiasis from 2016 to 2022, and additional 10% to 15% counties (districts) endemic for clonorchiasis were sampled from Guangdong Province as mobile surveillance sites each year from 2016 to 2022. A village (community) was randomly selected from each surveillance site according to the geographical orientations of east, west, south, north and middle, and subjects were randomly sampled from each village (community). C. sinensis eggs were detected in subjects’ stool samples using the Kato-Katz technique, and the prevalence and intensity of C. sinensis infections were calculated. In addition, subjects’ gender, age, ethnicity, educational level and occupation were collected. The Guangdong Provincial 1:1 million electronic map in vector format was downloaded from the National Geomatics Center of China, and kernel density analysis and spatial autocorrelation analysis of C. sinensis human infections in Guangdong Province from 2016 to 2022 were performed using the software ArcGIS 10.7. Results A total of 153 188 residents were tested for C. sinensis infections in Guangdong Province from 2016 to 2022, including 75 596 men (49.35%) and 77 592 women (50.65%), and there were 5 369 residents infected with C. sinensis, with 3.50% overall prevalence of infections. The prevalence rates of severe, moderate and mild C. sinensis infections were 0.76%, 7.26% and 91.97% among C. sinensis-infected residents in Guangdong Province from 2016 to 2022, and there were age-, gender-, ethnicity-, occupation- and educational level-specific prevalence of C. sinensis human infections (χ² = 2 578.31, 637.33, 52.22, 2 893.28 and 1 139.33, all P values < 0.05). Global spatial autocorrelation analysis showed a cluster in the prevalence of C. sinensis human infections in Guangdong Province (Moran’s I = 0.63, Z = 27.31, P < 0.05). Kernel density analysis showed that the prevalence of C. sinensis human infections with a high kernel density in Guangdong Province was mainly distributed along the Zhujiang River basin in Pearl River Delta areas, followed by in eastern and northern Guangdong Province. In addition, local spatial autocorrelation analysis identified 73 high-high clusters of the prevalence of C. sinensis human infections in Guangdong Province. Conclusions The prevalence of C. sinensis human infections was high in Guangdong Province from 2016 to 2022, and mild infection was predominant among all clonorchiasis cases, with spatial clusters identified in the prevalence of C. sinensis human infections. Targeted clonorchiasis control measures are required among high-risk populations and areas.