Spatial And Temporal Dynamics Of Hemorrhagic Fever With Renal Syndrome And Host Animals In Xi'an

Hemorrhagic fever with renal syndrome (HFRS) is a natural focal disease caused by different species of Hantaviruses, and the main host animal is murine-like animal. There two types of Hantaviruses may cause HFRS one is Hantaan virus (HTNV) whose host animal is Apodemus agrarius and the other is Seoul virus (SEOV) whose host animal is Rattus norvegicus in China. Shaanxi province is one of the high incidence areas of HFRS in China, the incidence of HFRS is on rise year by year since 2007, and total 2356 cases has detected in 2010, which was one of highest incidence in China, and about 90% of the total cases were detected in Xi’an. In order to get an insight into the composition, distribution and virus-carrying condition of host animals of HFRS in Xi’an, the correlation between their ecological features and virus-carrying rates as well as mice situation and human epidemic situation and the influence of different habitat factors on animal carrying HV. Nip capturing method was applied to investigate the density of host animals, and number of species and its habitat characteristic were recorded. RNA were extracted from the lungs tissue of host animal, gene sequence of M fragment from hantavirus genome was amplified and genotyping Hantavirus (HV), Using X2 test analysis of the density of animal as well as virus carrying rate and the density of animal in different habitat was determined by chi-square test and general linear modeling, respectively.1) Three animal identified animal reservoir were, Apodemus agrarius, Mus musculus, Crocidura suaveolens. virus-carrying rates was very low in both M. musculus and C. suaveolens, and our result indicated that Xi’an is still Apodemus type epidemic area, but we should focus on the situation of M. musculus carrying virus and whether Epidemic types should become mixed type from Apodemus type, in order to take measures to tackle new situations of prevention and control HFRS.2) The host animal of HFRS in Xi’an mainly was mainly found in the wild habitats, especially in the cropland and wasteland. The density of host animal in field were increased from April, and highest in August, then descent after November. There was significantly correlation between monthly density of host animal and virus carrying rate, but the incidence of HFRS was not correlated with monthly density host animal as well as virus carrying rate. There was no significant correlation in Index values of Hantavirus carriage of host animal and the incidence of HFRS in different years.3) The barrier action of mountain on HFRS spread is significant, river and larger population centers are closely related to the transmission of HFRS. The area close river has higher virus carrying rate, same as the area where has a certain distance from the larger population centers, harvesting has significantly influence on the density and virus carrying rate, which rose dramatically after harvest, and onset of HFRS trended to cluster in the same time, harvesting may be one of the most dangerous risk for people infect HFRS, in addition, animal diversity may have subtly restricts on HFRS spread, rich biodiversity may reduce risk of HFRS infection.4) Virus carrying rate were significantly correlated with host animal’s age, with the older in age, the higher of virus carrying rate. On which there was no significant difference of virus carrying between male and female animal.5) HFRS incidence in Xi’an city is still high, the incidence peak occurred in 2010, and then began a slow decline, there was more dramatic fluctuations of incidence in Chang’an District, Meanwhile, Zhouzhi County and Hu County should not be ignored, it’s worth noting that the incidence in Lintong District outbreak in recent years, We should pay attention to strengthen HFRS control and prevention. The main target groups of infecting HFRS were peasant and students. It would be particularly important for us to focus these two high-risk groups.We analyze characteristics of case spatial-temporal distribution and host animal population dynamics based on research of how it impact on HFRS by different habitat and other factor, and get good theory support to prevention and control of HFRS.