Objective To explore susceptibility of praziquantel(PQT) against Schistosoma japonicum in the repeated chemotherapy areas in Dongting Lake region of China. Methods Sixty mice were divided into two groups, and infected respectively by cercariae released from the infected snails which were collected from new and old endemic areas. After 5 weeks, the mice in each group were divided into control groups and treatment groups (PQT group). The mice in each PQT group were treated with a single oral dose of praziquantel (600 mg/kg). Three weeks post treatment, mice were dissected, and the number of adults, the stool eggs per gram (EPG), the liver EPG and the hatching rates were observed. Results The worm reduction rates of the PQT groups of new and old epidemic areas were 98.24% and 98.71% respectively, and the stool egg reduction rates 99.94% and 99.64%, the liver egg reduction rates 75.85% and 73.10%,and there were no significant differences between the new and old endemic areas. The stool hatching test was positive in the control groups, and negative in the PQT groups. Conclusion Susceptibility of praziquantel against Schistosoma japonicum does not decrease in repeated chemotherapy areas in Dongting Lake region.

The problems of non-standard use of pesticides, and excessive pesticide residues and excessive heavy metal, etc. are common in the productive process of safflower (Carthamus tinctorius) and they are the factors restricting the sustainable development of safflower industry. Pollution-free production is an effective measure to ensure high quality of safflower. This paper summarized the environment of production area, selection of improved varieties for the production in the local places and its characteristics, the standardized comprehensive agronomic management and pollution-free rational fertilization technology. Additionally, the pollution-free control of safflower pests and diseases should follow the principle of priority to prevention and comprehensive prevention. Agricultural, biological and physical control should be preferred to use, and be combined with safe and low toxicity of chemical control. The standardization and industrialization of safflower production were realized by the construction of a comprehensive control technology system of pests and diseases of pollution-free safflower, which promoted the healthy development of the safflower plantation industry and achieved pollution-free standards.