Study on the association between hantavirus infection and Rattus norvegicus / 中华流行病学杂志

<p><b>OBJECTIVE</b>To further understand the association of hantavirus (HV) harbored and transmitted in wild brown rats.</p><p><b>METHODS</b>Rattus norvegicus (n = 570) were trapped in 10 sites in Beijing. RT-PCR was used to test rodent lung samples for hantavirus infection. Unconditional multivariate logistic regression analysis was performed, with PCR positive as the dependent variable and the characteristics of Rattus norvegicus population as independent variables.</p><p><b>RESULTS</b>The overall HV prevalence in Rattus norvegicus was 9.1% (52/570). Significant association between HV infection in Rattus norvegicus and some biological characteristics of host population was observed. Adult Rattus norvegicus had a higher HV prevalence than juveniles. Males in the reproduction periods and rats with wounds were more likely to be infected with HV than others.</p><p><b>CONCLUSION</b>It was further confirmed that there existed parallel transmission of HV in Rattus norvegicus hosts. Aggression might be the primary mode of HV transmission among male Rattus norvegicus.</p>

Study on the molecular epidemiology of hantaviruse carried by hosts in northern suburb of Beijing / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate hantanvirus infection of captured rodents in Haidian district and Changping district of Beijing and to type hantavirus using molecular technique.</p><p><b>METHODS</b>The captured mice were classified and the density of distribution was calculated. Reverse transcription-polymerase chain reaction (RT-PCR) technique was used to amplify the partial M fragnments of hantaviruse. Several representative positive samples were sequenced and analysed by ClustalX (5.0) and DNAClub software.</p><p><b>RESULTS</b>A total of 414 animals were captured, among which Battus norvegicus was the dominant group. In Haidian district, the median infection rates with hantavirus were 13.14% in Battus norvegicus and 0 in Mus musculus Linnaeus. In Changping district, the average infection rates were 17.46% in Battus norvegicus and 3.57% in Mus musculus Linnaeus. Nucleotide sequences analysis showed that the virus detected all belonged to SEO-type. They clustered with Z37 virus and could be branched into 2 different subclades.</p><p><b>CONCLUSION</b>The major hosts of hantavirus in Haidian and Changping district were Battus norvegicus and the epidemic strains in the two districts of Beijing were genotyped as SEO-type. Nucleotide sequence and deduced amino acid sequence from different rodents were highly homologous, while nucleotide mutation had also been observed. Further studies are required to explore the possible virus sequence mutation.</p>

Spatial analysis on the distribution of hemorrhagic fever with renal syndrome by geographic information system in Haidian district, Beijing / 中华流行病学杂志

<p><b>OBJECTIVE</b>To analyze the spatial distribution of hemorrhagic fever with renal syndrome (HFRS) in Haidian district, Beijing and to explore the geographical characteristics of HFRS in highly endemic areas.</p><p><b>METHODS</b>Administration boundary layer was established under the background of 1:100,000 map in the ArcInfo 8.1 software. The HFRS cases from 1997 to 2002 were positioned on the map. Highly endemic areas were identified by spatial cluster analysis using SaTScan 3.0 software. Distribution of HFRS cases was shown in different colors and contours by spatial analysis of geographic information system (GIS).</p><p><b>RESULTS</b>Spatial Cluster Analysis of confirmed cases of HFRS identified in 1997 - 2002 in Haidian district showed that HFRS patients were not randomly distributed. The highly endemic areas were founded in Sujiatuo township, Yongfeng township, Shangzhuang township, Wenquan town and Bei'anhe township (relative risk = 4.43, P = 0.001). A thematic map of HFRS in haidian district was set up.</p><p><b>CONCLUSION</b>HFRS infections were not randomly distributed, since the distribution was related to geographic-environmental factors.</p>

Epidemiological characteristics of 403 patients with severe acute respiratory syndrome in Haidian district, Beijing / 中华流行病学杂志

<p><b>OBJECTIVE</b>To analyze epidemiological features of severe acute respiratory syndrome (SARS) in Haidian district, Beijing.</p><p><b>METHODS</b>Each SARS case was interviewed by trained investigator using standardized questionnaire followed a descriptive analysis.</p><p><b>RESULTS</b>Four hundred and three SARS cases were identified and 27 of them died from March 18 and May 31, 2003. The incidence rate of SARS was 18.0/100,000 with case fatality rate as 6.7% in Haidian district, Beijing. Seventy-four percent of patients were adults with higher risk in age group of 20 - 29 year. SARS patients were scattered around in 32 out of 33 streets and villages in this district. The disease appeared to be sporadic but the case of outbreaks in family or university only seen in three streets. The course of SARS epidemic in this district could be divided into three phases: initial-which last for days, peak-21 days and then rapid decline-for 26 days. Number of patients having had a history of close contact to other SARS were gradually decreasing along with the process of the epidemics (trend chi(2) = 8.800, P = 0.003). Seventy-two point seven percent of the SARS cases had been exposed to the injection in the hospital settings. When the epidemics came to a rapid decline, 85.7% of the patients diagnosed during that period could be traced down to have had the history of contacting SARS cases within their own families. The distribution of occupation was also showed significantly different in the three respective stages (chi(2) = 36.41, P < 0.01). Among the patients who could not be identified as having confirmed contact history, 26.6% having had outward activities and 47.6% of them visited hospitals, especially during the peak stage.</p><p><b>CONCLUSION</b>The intensity of SARS epidemic among the residents of Haidian district was recognized as similar to the other parts of Beijing. Nosocomial infection in hospital settings was most important cause responsible for the transmission of SARS in this district.</p>