Since 2010, a new rickettsiosis caused by Rickettsia parkeri, a species included in the spotted fever group (SFG) and transmitted by the tick Amblyomma ovale, has been described in Brazil. Considering that A. ovale does occur in the Espírito Santo state (ES), the present study aimed at preliminarily describing the epidemiology of R. parkeri in the Atlantic forest of this state. Between June 2016 and September 2018, 33 villages from nine municipalities of the ES were included in a study for the molecular detection and isolation of SFG rickettsiae from adult Amblyomma ticks collected on dogs with free access to the forest. Serologic screenings against SFG rickettsiae in these animals and their owners (humans) were performed through immunofluorescence assay (IFA) using antigens of Rickettsia rickettsii and R. parkeri. Additionally, local health secretariats were informed on clinical manifestations of R. parkeri infection and told to communicate any suspected case. A total of 280 adult ticks were collected and taxonomically classified as A. ovale (n = 152), Amblyomma aureolatum (n = 127) and Amblyomma sculptum (n = 1). Overall, Rickettsia DNA was detected in 12/266 ticks. The sequencing of PCR products revealed that 0.7% (1/144) and 0.8% (1/121) of the analyzed A. ovale and A. aureolatum ticks were infected by R. parkeri strain Atlantic rainforest, respectively, and 8.3% (10/121) of the A. aureolatum ticks infected by Rickettsia bellii. Among the above PCR-positive ticks, only one isolate from one A. aureolatum tick was successfully established in the laboratory. DNA extracted from the third passage of this isolate was designated as strain M9A and molecularly characterized using primers targeting the Rickettsia gltA gene, whose sequence matched 100% the corresponding sequences of R. bellii. Seroprevalence against SFG rickettsiae in sampled dogs (n = 83) was 41% or 57%, depending on the rickettsial antigen (R. rickettsii strain Taiaçu or R. parkeri strain Atlantic rainforest, respectively). A total of 37 (45%) canine sera showed titers to R. parkeri at least fourfold higher than to R. rickettsii antigen. Among humans, 10% (4/41) of the samples reacted to at least one rickettsial antigen, with the highest endpoint titer varying from 64 to 128 for R. rickettsii and R. parkeri; no human serum showed ≥4-fold difference between the highest endpoint titers. Finally, during the study period, suspicions on cases of R. parkeri-rickettsiosis were not informed by the health secretariats. Our results confirm the presence and exposure to R. parkeri strain Atlantic rainforest, associated with two anthropophilic tick species (A. ovale and A. aureolatum) parasitizing domestic dogs with unrestrained access to forest areas. Consequently, the occurrence of R. parkeri infection in humans inhabiting the Atlantic forests of ES should not be discarded.

自2010年以来，巴西描述了一种由立克次体立克次体引起的新立克次病，该病包括在斑点热病群（SFG）中，并由卵形tick虫传播。考虑到椭圆菌确实发生在圣埃斯皮里图州（ES），因此本研究旨在初步描述该州大西洋森林中的R. parkeri流行病学。在2016年6月至2018年9月之间，来自ES的9个城市的33个村庄被纳入一项分子检测和分离成人成年弱视的SFG立克次体的研究中可自由进入森林的狗身上收集的s。使用立克次氏立克次体和帕克氏杆菌的抗原，通过免疫荧光测定法（IFA）在这些动物及其所有者（人类）中进行了针对SFG立克次氏体的血清学筛查。此外，还向地方卫生秘书处通报了帕克氏杆菌感染的临床表现，并告知他们任何可疑病例。总共收集了280个成年s，并按分类将其分类为卵圆曲霉（n = 152），金黄色盲肠（n = 127）和浮雕雕塑（n = 1）。总体而言，立陶宛在12/266滴答中检测到DNA。PCR产物的测序表明，分析的椭圆形and和金黄色。的0.7％（1/144）和0.8％（1/121）分别受R. parkeri株大西洋雨林感染和8.3％（10 / 121）感染了立克次氏菌的金黄色葡萄球菌。在上述PCR阳性tick中，实验室仅成功建立了一种金黄色葡萄球菌tick的分离株。从该分离株第三次传代中提取的DNA命名为M9A菌株，并使用针对立克次体gltA基因的引物进行分子鉴定，其引物的序列与100％的相应序列匹配。R. bellii。根据立克次体抗原（分别为R. rickettsii菌株Taiaçu或R. parkeri菌株Atlantic Rainforest ），在抽样犬（n = 83）中，针对SFG立克次体的血清阳性率为41％或57％。总共37（45％）犬血清显示对R. parkeri的滴度比对R. rickettsii抗原的滴度至少高四倍。在人与人之间，样品的10％（4/41）反应，至少一种抗原立克次体，具有最高终点效价变化从64到128为R. rickettsii和R. parkeri ; 没有人的血清显示最高终点滴度之间的差异≥4倍。最后，在研究期间，对R. parkeri病例的怀疑卫生秘书处未告知-立克次氏病。我们的结果证实了存在和暴露于R.parkeri品系大西洋雨林的情况，该雨林与两种嗜人壁虱物种（卵形曲霉和金黄色曲霉）相关，寄生于无限制进入森林地区的家犬。因此，不应丢弃居住在ES大西洋森林中的人类中的R. parkeri感染。