Study on the characteristics of Tsutsugamushi disease in the epidemic areas of south islands in China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the increasing incidence and the characteristics of Tsutsugamushi disease in the areas of Nan Peng Lie islands, Nan Ao island, Wan Shan archipelago, Nao Zhou island and Lei Zhou peninsula, located in the southern part of China and to develop strategies for preventive measures.</p><p><b>METHODS</b>Both epidemiological investigation, isolation and gene identification of Orientia tsutsugamushi, as well as pilot preventive measures were carried out.</p><p><b>RESULTS</b>These islands belonged to the epidemic area of south subtropical zone of Tsutsugamushi disease. The main host was Rattus norvegicu and the overall rates of infection on Orientia tsutsugamushi were 22.78%-33.75%. The main biological vector was Leptotrombidium (Leptotrombidium) deliens and the rates of infection on Orientia tsutsugamushi were 40.00%-75.00%. 25 strains of Orientia tsutsugamushi had been isolated from Rattus norvegicu and Leptotrombidium (Leptotrombidium) deliens. Results showed that the isolated strains of Orientia tsutsugamushi were 15 Karp, 8 Kato, 2 Yonchon. Results from serological studies showed that the positive rate of anti-Orientia tsutsugamushi antibodies was high, in both residents and soldiers stationed in these islands. On these islands, rats and biological vectors were killed. Results showed that these measures had positive impact in reducing the incidence.</p><p><b>CONCLUSION</b>Islands from the southern part of the country belonged to the epidemic area of Tsutsugamushi disease. People visiting this areas should be under protection.</p>

Development and application of geographic information system of Aedes vector in Chaozhou city, Guangdong province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore the spatial distribution character of dengue fever and the change of Aedes' population, so as to provide macroscopical decision-making evidences of prevention and supervision on dengue fever.</p><p><b>METHODS</b>(1) Collecting data on morbidity of dengue and supervision on vector's population in the corresponding period. (2) Drawing digitized map of Chaozhou in scale of 1:50,000, including elements of boundary, residential areas, road and traffic, altitude, water systems etc. (3) Measuring the latitude and longitude of center position of surveillance safes on the scene. (4) Processing spatial analysis by the ArcGIS 8.5 software.</p><p><b>RESULTS</b>Distribution of Aedes showed spatial cluster in Chaozhou, while its density was related to the distance to the watersides. The closer to the watersides, the higher the density was. Map on spatial distribution showed that although the Aedes epidemic situation changed yearly, but primarily be kept in high, middle, low regions. Cross-validation effects of the distribution maps were satisfactory.</p><p><b>CONCLUSION</b>Geographic information system was promising in analyzing data on dengue fever, and better than other routine research methods.</p>

Study on the distribution of malaria in Hainan province through spatial local interpolation technique / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore the spatial distribution of malaria in Hainan province.</p><p><b>METHODS</b>Maps of spatial distribution on malaria incidence in Hainan province from 1995 to 1999 were produced, using a spatial local interpolation technique in the ArcGIS 8.1 software. Cross-validation techniques were used to evaluate the fitness of the distribution maps.</p><p><b>RESULTS</b>The spatial distribution of malaria in Hainan province from 1995 to 1999 showed that the incidence of malaria in the southern part of Hainan province were higher than that in the north. In the south, the incidence of malaria in east coastal areas were higher than that of other parts, especially in Wuzhi and Yingge mountains. The prediction error of the cross-validation indicated that the spatial distribution maps of malaria in Hainan had good fitness of malaria incidence of Hainan province.</p><p><b>CONCLUSION</b>Spatial local interpolation technique seemed to be promising in describing the spatial distribution of malaria.</p>