The virus family Arenaviridae is a diverse group of RNA viruses and includes the etiologic agents of several emerging zoonoses that are characterized by high case-fatality rates.The purpose of this article is to review the major features of the zoonotic arenaviruses from the angles of their taxonomy and classification,epidemiology and ecology,mode of transmission,clinical signs,prevention and control,etc.Which are important for the reason that viruses causing severe disease in humans are re-emerging somewhere the world.

Objective To make the quality control of the tests used in the schistosomiasis survey. Methods A specific new method was proposed to test the independency of three tests in order to control the quality of the survey. Simulated data and real survey data were used to discuss the adaptability of the method. Results The simulated data and the real data both revealed that the new method could be used to test the independency of three tests. Conclusions The new approach can be applied in the quality control of schistosomiasis survey and is of high value for wide application.

Objective To explore the application of amplified fragment length polymorphism (AFLP) in the study of genetic diversity of Oncomelania hupensis. Methods A snail was taken at random from Dali region, Yunnan Province and Yueyang City, Hunan Province respectively, and DNA was drawn with guanidinium thiocyanate and resin et al. Genomic DNA was amplified selectively by the AFLP technique with 64 pairs of primers, and the polymorphism of PCR products was examined by SDS-PAGE. Results The number of AFLP markers was between 5 and 55 for a pair of primers. The average number of a pair of primers was 38.30 (95% CI 36.03-40.57) for the snail from Yunnan Province, and 39.14 (95% CI 36.71-41.57) for the one from Hunan Province. For a pair of primers, the number of amplified polymorphic markers was between 3 and 37, and the polymorphic rate was between 28.6% and 76.2%, the average, 23.67 (95% CI 22.12-25.22) and 47.36%(95 %CI 45.22%-49.50%), respectively. The average similarity between the two populations was 0.69 (95% CI 0.67-0.70). Conclusion The AFLP technique is a new path for classifying Oncomelania hupensis and studying the genetic diversity of it.[

Mathematical model has been increasingly applied in the description of the transmission of schistosomiasis, the prediction and selection of schistosomiasis prevention measures, and it has being developed constantly. This paper briefly introduces several typical mathematical models for transmission of schistosomiasis and summarizes their advancements.

A quantitative study on human water contact was carried out in an endemic area of schistosomiasis japonica. The information relating to frequency, duration and intensity of each activities was obtained from 390 persons (93% of all) aged 5-59 and 10 days of each season in 1987 was surveyed by using systematic sampling. Socioeconomic investigation and stool examination were also performed on the same population. It is found that cutting grass and fishing are the most important activities, as well as swimming and bathing. The accumulated index ofexposure is high in spring and summer, low in autumn and rare in winter. The peak contact is 8-12 o'clock in the morning. The reasons of contact are different between males and females. And the peak contact is at teen aged youth. Studies on water contact and socioeconomic factors show that there are more contacts in peasants than in those with other occupations. Rich farmers who has more savings contact less. The contacts seem more frequent in those whose family water supply is from infected water. The stepwise regression analysis shows that the most important factor relating to the infection of schistosomiasis japonica are index B of exposure (accumulation of duration ? intensity). The infected water supply of family and education were two other factors relating to the infection.

ObjectiveTo investigate the dynamic changes of T helper (Th) responses and hepatic granuloma development during Schistosoma japonicum infection and to evaluate the possible correlation between the Th1/Th2 cytokines and pathological liver damage. MethodsSera from both Schistosoma japonicum infected C57BL/6 mice and uninfected controls were measured for interferongamma (IFN-γ), interleukin (IL)-4 and IL-13 at week 4, 6, 8 and 12 post-infection. At the same time, the splenic Th1/Th2 ratio was examined. The development of liver granulomas in infected mice was also observed and the correlation between the cytokines and granulomas were assessed. Wilcoxon test and Spearman rank correlation test were performed for data analysis. ResultsSerum IFN-γ level in infected mice was (2. 835±0. 049) lgpg/mL at week 4 post infection, which was significantly higher than that in controls [(1. 787 ± 0. 174) lgpg/mL, Z= - 2. 646, P = 0. 008]. Thereafter, the level declined after week 6, but remained higher than controls at the end of 12-week experiment (Z= -2.457, P=0. 014). IL-4 and IL-13 levels did not increase until week 6 (Z=-2. 646,P=0. 008;Z=-2. 646,P=0. 008), and peaked at week 8. After soluble egg antigen (SEA) stimulation, splenic Th1/Th2 ratio in infected mice was 0.5 (95％ CI 0. 2-1.2) at week 8 and 0.3 (95％ CI 0. 3-0.6)at week 12 post infection, both of which were significantly lower than those in uninfected controls (week 8: Z=2. 173, P=0.030; week 12:Z=2.551, P=0.011). Compared with unstimulated splenic cells, splenic Th1/Th2 ratio after SEA stimulation significantly decreased at week 8 (Z=2. 236, P=0. 025) and week 12 (Z=3. 130, P=0.002). Granulomas were first observed in livers at week 6 and the size kept on increasing. A negative correlation between serum IL-13 and the diameter of liver granulomas was discovered at week 12 post infection (r=0. 636, P= 0. 048). Conclusions Th1 response is dominant during the early stage of Schistosoma japonicum infection.However,followed by oviposition, Thl response declines and meanwhile a strong Th2 response gradually develops. Therefore, Th2 response probably plays a role in the development of hepatic granulomas.

Objective　To evaluate the effect of occupation al protection measures on reducing blood exposure. Methods　A s urvey was carried out to investigate medical staff in Shanghai hospitals. Sing le-factor and multi-fa ctor analysis measures were used. Results　The more protection m eas ures adopted, such as gloves using, occupational training and strict rules and r egulations, the less occupational exposure. The resul ts also showed that there were statistical difference. Conclusions　It is important for medical staff to strength occupational protection in order to avoid acqu iring hospital infection.

Schistosomiasis is a neglected tropical disease which is socioeconomically devastating and a significant cause of morbidity in endemic countries or regions. Some countries and regions have brought down the prevalence of schistosomiasis through positive prevention and control programs. However in the past few years with the social and economic development and globalization re?emergence and spread of schistosomiasis led to a growing concern that new endemic areas may occur. This article analyzes the epidemiological situation and the strategies to control schistosomiasis in China and African countries.

A preliminary survey was done in 1980 in Jijiaba Village before the dike was built . The dike of 2. 5 km in length and 4m high was built along Baiyang River by the end of 1980 . The molluscicide NaPCP was used for snail control from 1981 to 1984 . After the entire control measures were completed in 1984, a follow-up survey was conducted as to measure the impact of control measures on prevalence of schistosomiasis and population of snail from 1985 to 1989 . All of the results suggested that these control measures were very successful. The transmission of schistosomiasis in this area has been prevented since 1984 .

Objective To explore the geographic pattern of morphologic variation within snail populations across the mainland of China. Methods Twenty-one snail populations from the different regions were collected, and Shannon-Winer index and Euclidean distances within populations were used to analyze the spatial distribution of morphologic variation of Oncomelania hupensis. Results Longitude correlated significantly with Shannon-Winer index and Euclidean distances within populations, and the correlation coefficients were 0.719(P