[Toxicity of niclosamide with plastic film mulching to fish].

OBJECTIVE: To observe the toxicity of niclosamide with plastic film mulching to fish. METHODS: A ditch with Oncomelania snails was selected as the study site, and it was divided into a control group and a molluscicide group. After the river closure, the molluscicidal group was sprayed with niclosamide with a dosage of 2 g/m2, and then covered with plastic film; no molluscicide measure was implemented in the control group. The toxicity of the molluscicide to carp fish in resting and flowing water environment was observed. RESULTS: In flowing water, the death rates of carp fry of the molluscicidal and control groups showed no statistical difference 7 d after the film mulching (P = 0. 680), and no carp fry died in the 2 groups after plastic film taking off for 4 d. The death rates of carp fry between the 3 sites (with a distance of 50, 100 and 150 m from the molluscicidal group, respectively) and the control group had no statistical difference 7 d after film mulching (P = 0.955), and no dead fry was discovered 4 d after taking off the film. In downstream, for the death rates of carp fry, there was no difference between the molluscicidal group and the control group (P = 0.376). The death rates of snails before and after the molluscicidal experiment showed a significant difference (P < 0.01). CONCLUSIONS: The technology of niclosamide molluscicide with plastic film mulching can not only improve the molluscicidal effect, but also avoid the toxicity to fish, which is suitable for special environment such as a fish pond.

[Molluscicidal effect of film on ditches in mountainous schistosomiasis endemic regions].

OBJECTIVE: To evaluate the molluscicidal effect of film on ditches in mountainous schistosomiasis endemic regions. METHODS: A ditch with Oncomelania hupensis snails was selected as experimental field. The ditch was divided into 3 parts (groups): a niclosamide plus film covering group (film covering after spraying by wettable powder of 50% niclosamide ethanolamine salt upon 2 g/m2), a film covering group (film covering directly without niclosamide spraying), and a control group (no molluscicidal measures). The snail investigation was performed 7, 10, 40, 60 d and 90 d after film covering. The temperatures outside and inside film were determined twice a day during the experiment. RESULTS: The temperature inside the film was significantly higher than that outside the film (t = 4.12, P < 0.01). Compared with the densities of living snails before the experiment, the densities of living snails decreased by 99. 01% and 67.71% seven days post-film in the niclosamide plus film covering group and film covering group respectively; 96.58% and 93.06% ten days post-film respectively; both 100% forty days post-film. The multi-factor regression model indicated that covering film with niclosamide applying, extending film covering time, and increasing cumulate temperature inside film could enhance the molluscicidal effect. CONCLUSIONS: The film covering has well molluscicidal effect. The molluscicidal effect of covering film with niclosamide is better than that of covering film alone in short time. However, the covering film alone also has good molluscicidal effect when increasing covering time.

[One family investigation and risk factors analysis of developmental dysplasia of the hip].

OBJECTIVE: To investigate the clinical manifestations and risk factors of the patients from developmental dysplasia of the hip(DDH) family. METHODS: Detailed epidemiology investigation, physical examination, functional movement assessment, lab test and X-ray examination were applied to the whole members of a DDH family. RESULTS: In the family with 9 generations and 218 persons, the incidence of DDH was 31.03% in 145 survivors. Patients mainly manifested bilateral knee and hip joint pain, flexion contracture of hip, limitation in internal and external rotation of hip; a few had arthritic functional disorder, deformation, and limp. The radiography illustrated shallow acetabulum with increased inclination, which encompassed the femoral head badly. Deformation of the femoral head, narrow joint space and osteophyte were also found by X-ray examination. The main risk factors of DDH were genetic factors, gender, birth season etc. The son or daughter with one or two DDH parents had a higher risk for developing DDH than those with no DDH parents. Furthermore, first-degree relatives of the DDH patients also had a greater chance to develop DDH than second-degree relatives and third-degree relatives. The incidence among females was higher than males, and the family member who was given birth in winter had a highest risk for developing DDH. However, there was no difference between incidence of DDH in children and youths and in adults; the incidence of DDH in the immigrants with no blood relationship also did not differ from the incidence of DDH in the family member. CONCLUSION: The genetic factors play an important role in the development of DDH, so do the environmental factors.