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.

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

Objective To study current situation and existed problems in the public health emergency alert and response system so as to formulate more advices to consummate it and help to establish a more reasonable system adapting to our country. Methods A qualitative study was carried out among CDC working staff including two focus group discussions(FGD). Results Although government had put more emphasis on public health,increasing its devotion and strengthening the alert and response capability after SARS outbreak, some problems still existed, such as ① absence of correlative laws and rules; ② lack of government devotion; ③ insufficient utilization of surveillance information; ④ lack of the canonical response guidance. Conclusions With regard to the building up of the public health emergency alert and response system, the following proposals are put forward: increasing payout on public health; consummating the construction of disease surveillance network; affording more education and training to correlative staff engaged in the disease control to improve their abilities.

Objective To explore morphologic variations and their spatial correlation among Oncomelania hupensis populations from the mainland of China. Methods Twenty-seven snail populations from ten provinces were collected. The morphologic indices of shells and geographic distances between the snail spots were measured respectively, and the morphologic variations among snail populations and the correlations between morphologic variations and geographical distances were analyzed. Results The median of Euclidean distances was 3.24 (95% CI: 2.88-3.81) among 20 snail populations of O.h.hupensis including a snail population from Guangxi Province, and was 3.15 (95% CI: 2.86-3.76) excluding the Guangxi snail population; the median was 1.69 (95% CI: 1.33-2.27) among 6 populations of O.h.robertsoni. Whether including a snail population from Guangxi Province or not, the median among O.h.robertsoni was less than that among O.h.hupensis (P0.05). The correlation coefficient was 0.2655 for O.h.hupensis including a snail population from Guangxi Province, 0.2567 not including it; and was 0.3121 for ribbed-shell population. Conclusions Morphologic variation among O.h.hupensis is bigger than that among O.h.robertsoni, and morphologic variation among ribbed-shell populations is bigger than that among smooth-shell populations. There is significant spatial structure among ribbed-shell snail populations of Oncomelania hupensis distributed in the mainland of China.

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 .

The elimination of Oncomelania hupensis snails is important to schistosomiasis control. Recently,the application of molluscicidal organisms is considered as a safe and efficient method for snail elimination. In order to provide scientific evi?dences for effective control of O. hupensis and schistosomiasis,this paper summarizes the researches of molluscicidal microor?ganisms against O. hupensis.