Kaplan J E, Newhouse V F
Am J Trop Med Hyg. 1984 Nov;33(6):1281-2. doi: 10.4269/ajtmh.1984.33.1281.
To study the time of onset of cases of Rocky Mountain spotted fever (RMSF) in relation to mean winter temperature, average daily solar radiation, elevation, and potential climax vegetation, we analyzed cases of RMSF from a 19-state area in the southeastern United States during the years 1970-1980 according to the counties in which patients resided. A bimodal incidence of RMSF, with peak onset of cases in mid-May and in mid-July, was noted in the oak-hickory-pine, oak-hickory, and Appalachian oak zones of potential climax vegetation during the years 1970-1974. In 1975-1980, however, coincident with an increase in incidence of RMSF, a single peak of illness in mid-June was observed in the oak-hickory-pine zone, where the number of cases of RMSF was highest; bimodality persisted in the oak-hickory and in the Appalachian oak zones. Analysis of cases in the zones in which bimodality persisted indicated that the first peak of illness may predominate in northern, cooler areas, and the second peak, in southern, warmer areas.
为了研究落基山斑疹热（RMSF）病例的发病时间与冬季平均温度、日平均太阳辐射、海拔以及潜在的顶极植被之间的关系，我们根据患者居住的县，分析了1970年至1980年间美国东南部19个州地区的RMSF病例。在1970 - 1974年期间，在潜在顶极植被的橡树 - 山核桃树 - 松树、橡树 - 山核桃树和阿巴拉契亚橡树区域，发现RMSF发病率呈双峰模式，病例发病高峰在5月中旬和7月中旬。然而，在1975 - 1980年期间，随着RMSF发病率的增加，在橡树 - 山核桃树 - 松树区域观察到6月中旬出现单一发病高峰，该区域RMSF病例数最高；在橡树 - 山核桃树和阿巴拉契亚橡树区域则持续存在双峰模式。对双峰模式持续存在的区域的病例分析表明，发病的第一个高峰可能在较凉爽的北部地区占主导，而第二个高峰在较温暖的南部地区占主导。
