ABSTRACT:As the only intermediate host of Schistosoma j aponicum ,Oncomelania hupensis is an important link of schis‐tosomiasis .It plays an important role in the transmission of schistosomiasis .This article mainly demonstrates the following as‐pects :the invasion of schistosome miracidium into O .hupensis ,the growth of sporocyst ,and the mature and escape of cercari‐ae ,which would provide laboratory data from literatures for revealing the symbiotic relationship between O .hupensis and S . japonicum .However ,the symbiotic relationship between O .hupensis and S .japonicum is too complex to description com‐pletely .Therefore ,the symbiotic relationship will be the focus of future research .

Objective To investigate the prevalence of occupational diseases and treatment implementation in migrant workers in Hunan,China,and to provide a scientific basis for related departments to develop preventive and treatment measures and social security system for migrant workers.Methods A retrospective investigation was performed in 2015 to collect the information of occupational diseases in migrant workers,and age,type of work,type of occupational disease,and implementation of employment injury insurance for occupation diseases were analyzed.Results The migrant workers with occupational diseases accounted for 50.43％ (11 280/22 368) of all patients with occupational diseases in Hunan,among whom 99.4％ (11 212/11 280) were male workers.The mean age of migrant workers with occupational diseases was 55 years.The types of occupational diseases involved 6 categories such as occupational pneumoconiosis and occupational skin diseases,totaling 42 legal occupational diseases;98.31％ of all migrant workers (11 089/11 280) had occupational pneumoconiosis.The main types of work were underground coal miners (62.42％),heading drivers (29.79％),and haulage workers (2.20％) in coal mines and non-coal mines.A total of 27.25％ migrant workers with occupational diseases (2 072/7 605) enjoyed employment injury insurance,and 20.84％(1 585/7 605) did not receive any medical or life compensations.Conclusion The occupational diseases in migrant workers in Hunan are mainly pneumoconiosis,and a large proportion of those with occupational diseases do not enjoy implementation of treatment.Coal mines and non-coal mines are the high-risk areas for occupational diseases in migrant workers and should be the focus of prevention and control.

Objective:To analyze the epidemiological characteristics of pneumoconiosis in Hunan Province.Methods:In November 2018, we collected the type of work, pneumoconiosis type, pneumoconiosis stage, length of service, age of onset and complications of pneumoconiosis cases diagnosed by Hunan occupational disease prevention and control hospital from January 2017 to October 2018. A total of 3 325 cases of pneumoconiosis were collected, including 651 cases (19.58%) of occupational pneumoconiosis and 2674 cases (80.42%) of clinically diagnosed pneumoconiosis. The measurement data were expressed by ± s. The comparison between groups was performed by independent sample t test and one-way ANOVA. Results:The age of 651 patients with occupational pneumoconiosis was 35.59-85.15 years old, the average age of onset was (54.27±8.29) years, and the average exposure to dust was (14.74±8.60) years. 2 674 cases of clinically diagnosed pneumoconiosis were 26.85~87.02 years old. The average age of onset was (55.26±7.38) years, and the average exposure time was (18.83±9.35) years. Compared with silicosis patients, coal workers' pneumoconiosis patients had longer exposure time, the difference was statistically significant ( P<0.05) , and the difference was statistically significant ( F=3.678, P<0.05) . There were no complications in 651 cases of occupational pneumoconiosis. Among 2 674 cases of clinically diagnosed pneumoconiosis, 710 cases (26.55%) had complications. Conclusion:Further attention should be paid to the clinical diagnosis of pneumoconiosis in Hunan Province.

Objective To investigate the prevalence of occupational diseases and treatment implementation in migrant workers in Hunan,China,and to provide a scientific basis for related departments to develop preventive and treatment measures and social security system for migrant workers.Methods A retrospective investigation was performed in 2015 to collect the information of occupational diseases in migrant workers,and age,type of work,type of occupational disease,and implementation of employment injury insurance for occupation diseases were analyzed.Results The migrant workers with occupational diseases accounted for 50.43％ (11 280/22 368) of all patients with occupational diseases in Hunan,among whom 99.4％ (11 212/11 280) were male workers.The mean age of migrant workers with occupational diseases was 55 years.The types of occupational diseases involved 6 categories such as occupational pneumoconiosis and occupational skin diseases,totaling 42 legal occupational diseases;98.31％ of all migrant workers (11 089/11 280) had occupational pneumoconiosis.The main types of work were underground coal miners (62.42％),heading drivers (29.79％),and haulage workers (2.20％) in coal mines and non-coal mines.A total of 27.25％ migrant workers with occupational diseases (2 072/7 605) enjoyed employment injury insurance,and 20.84％(1 585/7 605) did not receive any medical or life compensations.Conclusion The occupational diseases in migrant workers in Hunan are mainly pneumoconiosis,and a large proportion of those with occupational diseases do not enjoy implementation of treatment.Coal mines and non-coal mines are the high-risk areas for occupational diseases in migrant workers and should be the focus of prevention and control.

Objective:To analyze the epidemiological characteristics of pneumoconiosis in Hunan Province.Methods:In November 2018, we collected the type of work, pneumoconiosis type, pneumoconiosis stage, length of service, age of onset and complications of pneumoconiosis cases diagnosed by Hunan occupational disease prevention and control hospital from January 2017 to October 2018. A total of 3 325 cases of pneumoconiosis were collected, including 651 cases (19.58%) of occupational pneumoconiosis and 2674 cases (80.42%) of clinically diagnosed pneumoconiosis. The measurement data were expressed by ± s. The comparison between groups was performed by independent sample t test and one-way ANOVA. Results:The age of 651 patients with occupational pneumoconiosis was 35.59-85.15 years old, the average age of onset was (54.27±8.29) years, and the average exposure to dust was (14.74±8.60) years. 2 674 cases of clinically diagnosed pneumoconiosis were 26.85~87.02 years old. The average age of onset was (55.26±7.38) years, and the average exposure time was (18.83±9.35) years. Compared with silicosis patients, coal workers' pneumoconiosis patients had longer exposure time, the difference was statistically significant ( P<0.05) , and the difference was statistically significant ( F=3.678, P<0.05) . There were no complications in 651 cases of occupational pneumoconiosis. Among 2 674 cases of clinically diagnosed pneumoconiosis, 710 cases (26.55%) had complications. Conclusion:Further attention should be paid to the clinical diagnosis of pneumoconiosis in Hunan Province.