Departamento de Parasitología, Universidad Autónoma Agraria Antonio Narro, Unidad Laguna, Coahuila, Mexico.
Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, Durango, Mexico.
Parasit Vectors. 2019 Mar 26;12(1):130. doi: 10.1186/s13071-019-3377-z.
The aim of this study was to detect and molecularly identify Rickettsia spp. in Rhipicephalus sanguineus (sensu lato) collected from free-roaming dogs in 30 communities from five municipalities in the south of Coahuila State, northern Mexico, where Rocky Mountain spotted fever is endemic.
In total, 60 dogs from each municipality were examined for engorged ticks. DNA was isolated from tick pools and conventional PCR assays targeting the 23S-5S ribosomal RNA intergenic spacer and outer membrane protein (ompA) gene of Rickettsia spp. were performed.
All ticks (n = 1238) were morphologically identified as R. sanguineus (s.l.). Six pools (each with six engorged females) from four municipalities were positive to Rickettsia spp. DNA sequencing and phylogenetic analyses confirmed the presence of R. rickettsii and R. rhipicephali in R. sanguineus (s.l.) in these ticks.
This study confirms the presence of R. rickettsii and R. rhipicephali in R. sanguineus (s.l.) from stray dogs in the south of Coahuila. This suggests that stray dogs may play a role in the inter-municipal dissemination of infected ticks in this region. Further research is required to assess whether ticks from stray dogs could serve as good indicators for the molecular xenomonitoring of R. rickettsii in this region. Considering that R. sanguineus (s.l.) is a proven vector of R. rickettsii in Mexico, increased awareness regarding permanent tick control in dogs is warranted.
本研究旨在检测并分子鉴定来自墨西哥科阿韦拉州南部五个城市 30 个社区的自由放养犬中的游离蜱（Rhipicephalus sanguineus（sensu lato）中是否存在斑点热立克次体。
从每个城市的 60 只狗身上检查饱血的蜱。从蜱群中分离 DNA，并进行针对立克次体属的 23S-5S 核糖体 RNA 基因间 spacer 和外膜蛋白（ompA）基因的常规 PCR 检测。
所有蜱（n=1238）在形态学上均被鉴定为 R. sanguineus（s.l.）。来自四个城市的六个蜱群（每个群有六只饱血雌性）的 DNA 测序和系统发育分析证实了这些蜱中存在 R. rickettsii 和 R. rhipicephali。
本研究证实了在科阿韦拉州南部的流浪犬中存在 R. rickettsii 和 R. rhipicephali 感染的 R. sanguineus（s.l.）。这表明流浪犬可能在该地区感染蜱的市际传播中发挥作用。需要进一步研究来评估来自流浪犬的蜱是否可以作为该地区 R. rickettsii 分子 xenomonitoring 的良好指标。鉴于 R. sanguineus（s.l.）是墨西哥证明的 R. rickettsii 的传播媒介，应加强对犬只永久性蜱控制的认识。
