Magnarelli L A, Anderson J F, Philip R N, Burgdorfer W, Casper E A
Am J Trop Med Hyg. 1981 May;30(3):715-21. doi: 10.4269/ajtmh.1981.30.715.
To compare rickettsial infectivity and seropositivity rates against spotted fever group (SFG) rickettsiae, ticks and wild mammals were collected from three areas where Rickettsia rickettsii was thought to be enzootic in Connecticut during 1978-1979, and from four additional sites (with no reported human cases) between 1976 and 1979. Of the 1,001 Dermacentor variabilis examined by the hemolymph test, 59 (5.9%) contained rickettsia-like organisms; direct immunofluorescence tests verified the presence of SFT rickettsiae in 14 specimens. Prevalence of rickettsiae-infected ticks at Newtown, an area where human cases of Rocky Mountain spotted fever probably originated, was 2.2%. Rates for six other areas ranged between 0 and 6.3%. Isolations included Rickettsia montana from four ticks collected at Branford and Woodbridge, and R. rickettsii (R-like strain) from the blood of an acutely ill person. Microagglutination (MA) tests indicated that 15 (14.9%) of 101 Peromyscus leucopus (white-footed mice) from Newtown had agglutinins in titers greater than or equal to 1:8 against R. rickettsii, whereas five of 92 white-footed mice (5.4%) from Brandord, West Hartford, Woodbridge, and Sharon were considered MA-positive. Indirect microimmunofluorescence tests of Procyon lotor (raccoon) sera revealed antibodies to R. rickettsii in 33 of 69 (47.8%) samples from Newtown and in two of 60 (3.3%) from Guilford. Additionally, 17 raccoons had sera specific to R. montana (n = 8) or to the 369-C rickettsia strain (n = 9). Since rickettsia-positive ticks are high-titered seropositive mammals occurred at widely separated sites in Connecticut there are probably several foci of SFG rickettsiae distributed throughout the D. variabilis range.
为比较立克次体感染性以及针对斑点热群（SFG）立克次体的血清阳性率，于1978 - 1979年从康涅狄格州被认为存在立氏立克次体动物疫源地的三个地区，以及1976年至1979年间另外四个地点（无人类病例报告）采集蜱虫和野生哺乳动物。通过血淋巴试验检测的1001只变异革蜱中，59只（5.9%）含有类立克次体生物；直接免疫荧光试验证实14份标本中存在斑点热群立克次体。在可能是落基山斑点热人类病例起源地的纽敦，感染立克次体的蜱虫患病率为2.2%。其他六个地区的患病率在0至6.3%之间。分离出的菌株包括从布兰福德和伍德布里奇采集的四只蜱虫中分离出的蒙大拿立克次体，以及从一名急性病患者血液中分离出的立氏立克次体（R样菌株）。微量凝集（MA）试验表明，来自纽敦的101只白足鼠中有15只（14.9%）针对立氏立克次体的凝集素效价大于或等于1:8，而来自布兰福德、西哈特福德、伍德布里奇和沙龙的92只白足鼠中有5只（5.4%）被认为MA阳性。对北美浣熊血清进行的间接微量免疫荧光试验显示，来自纽敦的69份样本中有33份（47.8%）以及来自吉尔福德的60份样本中有2份（3.3%）含有针对立氏立克次体的抗体。此外，17只浣熊的血清对蒙大拿立克次体（n = 8）或369 - C立克次体菌株（n = 9）具有特异性。由于在康涅狄格州相距甚远的地点出现了立克次体阳性蜱虫和高滴度血清阳性哺乳动物，因此在变异革蜱分布范围内可能存在多个斑点热群立克次体疫源地。
