Clonorchiasis is one of the food?borne parasitic diseases. Adult parasites live in the human liver and gallbladder tube system,causing serious complications,such as gallstones,cholecystitis and cholangitis,and even bile duct cancer. The disease is very popular in our country,and the population infection rate is high. It is an important public health problem. Guang?dong Province is the earliest province being found of clonorchiasis and with serious epidemic. In the second national human para?sitic diseases distribution survey,the results showed that the average infection rate of Clonorchis sinensis in the epidemic areas in Guangdong was 16.42%. It is estimated that the population of C. sinensis infection is over 6 million. The prevention and con?trol of clonorchiasis in China is still in the initial stage currently and we face many challenges such as unclear epidemic charac?teristics and transmission mode,and lack of long?term prevention and control mechanism. This article introduces the epidemic situation of clonorchiasis and prevention and control strategies and measures in Guangdong.

Biomphalaria straminea,the intermediary host of Schistosoma mansoni,was found by survey in local areas of Shen-zhen City in 1981,which was the first finding of the snail in inland China. By 2013,the snail had spread in large range of Shen-zhen City and overspread to the surrounding regions,Dongguan City and Huizhou City. Due to the facts that Shenzhen City has many international communications and is a key area of labor export,with high population mobility,while the reports of S. manso-ni infection in the returnees of our country from Africa have been increasing recently,it must be paid a high attention to whether the epidemic or transmission of schistosomiasis mansoni may happen under the present circumstance. This paper initially discusses the finding,distribution,spreading and overspreading and transmission risk of B. straminea in inland China and puts forward some related control suggestions.

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.

In the past decades, people's work and life styles have dramatically changed during the rapid economic development and urbanization in China. A national survey reported that Chinese adults spend an average of 81% of daily time in indoor environment. Exposure to indoor air pollution plays key roles for human health but is likely to be neglected due on the relatively lower concentration levels and lower awareness among common people. Till now, published studies focus more on the pollution levels or the toxicological effects of indoor air pollutants but there is a lack of disease burden assessment attributable to indoor air pollution. In this review, several international studies were introduced on the disease burden estimation attributable to indoor air pollution, as well as the estimation methods. The current situation of national study was also reviewed. The strengths and limitations of the representative international studies were discussed. This review is helpful in providing data to guide the research on disease burden assessment attributable to indoor air pollution in China, and further helps to prioritize the indoor air pollution control based on disease burden ranking among pollutants and motivate public policies to protect the public health.

Caries is an important public health problem that affect the quality of life of residents, and microorganisms is the most important factor in its incidence. Probiotics are types of microorganisms that are beneficial to the human body and can regulate the microecological balance; thus, they have great potential for caries prevention. This paper reviews the caries prevention mechanism of probiotics, the research progress of probiotics of different genera, and the early colonization of probiotics and their safety. The literature review showed that probiotics aimed at caries prevention could colonize the oral cavity and played a role in caries prevention by inhibiting the growth of cariogenic bacteria and regulating host immunity. At present, probiotics used to prevent dental caries include probiotic Lactobacillus, Bifidobacterium and Streptococcus. The positive effect of probiotics on dental caries has been confirmed in most clinical trials. Because probiotics include a variety of strains with strain-specific functions, different strains may be the reason for the lack of caries prevention in some clinical trials. The potential probiotic strains with a strong colonization ability and caries prevention effect in the oral cavity are the research hotspots for caries prevention probiotics.

Dental fluorosis is a kind of enamel hypoplasia caused by excessive fluorine intake during tooth development, leading to the formation of enamel with a lower mineral content and increased porosity, which can affect dental function and patients′ appearance. The prevalence of dental fluorosis remains high on a global level, and its occurrence is affected by many factors. Excessive fluorine intake is a major risk factor for dental fluorosis. The ways of fluorine intake mainly includes the application of fluorides, daily diet and air. Since fluorides have been widely used in the prevention of caries in recent decades and the methods of exposure to fluorine have been increasing, increasing numbers of studies have been conducted to explore how fluoride can achieve a balance between the effective prevention of caries and the prevention of dental fluorosis. In addition, exposure to fluorine at earlier ages can also increase the risk of dental fluorosis, while the improvement of nutritional structure can affect dental fluorosis prevention. Genetic susceptibility, socioeconomic status and parental awareness may influence dental fluorosis. This article aimed to review the latest research progress on the factors influencing dental fluorosis and provide a reference for the prevention and treatment of dental fluorosis.

Objective: To investigate the risk factors for caries in preschool children to provide a scientific basis for the prevention and treatment of caries in primary teeth. Method: From July 2017 to September 2017, 183 children aged 3-6 who received treatment for caries in the Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, were randomly selected for recording of the caries status of deciduous teeth, and a questionnaire was collected from their guardians. Risk factors for caries in primary teeth were analyzed using SPSS 21.0 software． Results: The mean dmft (decayed, missing and filled teeth) value of all samples was 9.91 ± 5.12. There was no significant difference in dmft between boys (10.38 ± 5.26) and girls (9.55 ± 5.01) (t = -1.088, P > 0. 05). There were 40 cases (21.86%) in the mild caries group (dmft = 3.13 ± 1.34) and 143 cases in the severe group (dmft = 11.80 ± 4.07). Oral hygiene before one year of age, duration of tooth brushing, number of oral hospital examinations and frequency of sugar intake were significantly associated with caries status (P < 0.05). Children who brushed their teeth for less than 2 minutes and consumed sugar frequently had high dmft values. Duration of tooth brushing and frequency of sugar intake were significantly associated with caries in the primary teeth (P < 0.05). Conclusion Insufficient tooth brushing time and frequent sugar intake are major risk factors for deciduous caries.

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.