Programa de Pós-Graduação em Biociência Animal, Universidade Federal Rural de Pernambuco, Pernambuco, Brazil.
Laboratório de Parasitologia, Departamento de Biologia, Universidade Federal Rural de Pernambuco, Pernambuco, Brazil.
Vet Parasitol Reg Stud Reports. 2021 Dec;26:100649. doi: 10.1016/j.vprsr.2021.100649. Epub 2021 Sep 29.
Caatinga and Atlantic Forest are Brazilian biomes threatened by anthropogenic disturbances, which are a serious threat to biodiversity and favor the emergence of zoonotic pathogens. Capybara populations are increasingly present in urban and rural areas due to the loss of their natural habitats. There are no studies on the rickettsial infection in these rodents in Northeastern Brazil, although there are case records of Brazilian Spotted Fever (BSF) in this region. In this context, we evaluated rickettsial infection in capybaras and their ticks in four areas of the Atlantic Forest and Caatinga biomes in Northeastern Brazil. Blood sera from 21 capybaras were tested by indirect immunofluorescence assay (IFA) using Rickettsia rickettsii, R. parkeri, and R. amblyommatis antigens. Blood samples and ticks (Amblyomma sp., Amblyomma dubitatum and Amblyomma sculptum) were tested by PCR, targeting a fragment of the rickettsial gltA gene and R. bellii primers. Overall, 15 out of 21 capybaras (71.4%) reacted positively (titer ≥64) to at least one of the three Rickettsia antigens tested, with final titers ranging from 64 to 1024. No rickettsial DNA was found in capybara blood samples. Rickettsial DNA was detected in 22 of 31 adult tick pools using gltA gene, being all nine pools of A. sculptum and 16 of the 19 of A. dubitatum, but all samples were negative to R. bellii specific primers. All attempts to sequence the amplicon were unsuccessful, indicating a possible low rickettsial load in the tick samples. The present study reports for the first time the serological evidence of Rickettsia spp. infection in free-ranging capybaras and suggest the rickettsial infection in A. sculptum and A. dubitatum in the Caatinga and Atlantic Forest biomes in Northeastern Brazil.
卡廷加和大西洋森林是巴西的两个生物群落，受到人为干扰的威胁，这对生物多样性构成了严重威胁，并有利于人畜共患病病原体的出现。由于自然栖息地的丧失，水豚的数量在城市和农村地区越来越多。尽管该地区有巴西斑点热（BSF）的病例记录，但在巴西东北部的这些啮齿动物中，尚未对立克次体感染进行研究。在这种情况下，我们评估了巴西东北部大西洋森林和卡廷加生物群落的四个地区的水豚及其蜱中的立克次体感染情况。使用立氏立克次体、帕克立克次体和 amblyomma 立克次体抗原通过间接免疫荧光测定法（IFA）检测了 21 只水豚的血清。通过 PCR 检测血液样本和蜱（Amblyomma sp.、Amblyomma dubitatum 和 Amblyomma sculptum），针对立克次体 gltA 基因的片段和 R. bellii 引物进行检测。总的来说，21 只水豚中有 15 只（71.4%）对至少一种测试的三种立克次体抗原呈阳性反应（滴度≥64），最终滴度范围从 64 到 1024。在水豚血液样本中未发现立克次体 DNA。使用 gltA 基因在 31 个成蜱池中检测到立克次体 DNA，其中 9 个 A. sculptum 池和 19 个 A. dubitatum 池中的 16 个池，但所有样本对 R. bellii 特异性引物均为阴性。所有尝试对扩增子进行测序的尝试均未成功，表明蜱样本中的立克次体负荷可能较低。本研究首次报告了自由放养水豚感染立克次体的血清学证据，并表明巴西东北部卡廷加和大西洋森林生物群落中的 A. sculptum 和 A. dubitatum 存在立克次体感染。
