Barradas Patrícia F, Vilhena Hugo, Oliveira Ana Cristina, Granada Sara, Amorim Irina, Ferreira Paula, Cardoso Luís, Gärtner Fátima, de Sousa Rita
Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Oporto, Portugal.
Animal and Veterinary Research Centre (CECAV), University of Trás-os-Montes e Alto Douro (UTAD), Vila Real, Portugal.
Parasit Vectors. 2017 May 31;10(1):271. doi: 10.1186/s13071-017-2216-3.
Infections with tick-borne rickettsiae can cause diseases well known in humans but still not so well characterized in dogs. Susceptibility to infection depends on the virulence of Rickettsia spp. and only a few of them have been described to cause disease in dogs. The aim of this study was to investigate the exposure to Rickettsia spp. among a group of pet dogs from Luanda, Angola.
Out of 103 dogs included in the study, 62 (60.2%) were infested with ticks. Plasma specimens tested for serology by an immunofluorescence assay (IFA) revealed that six (5.8%) dogs had detectable immunoglobulin G (IgG) antibodies to spotted fever group Rickettsia (SFGR), with endpoint titers of 64 for two dogs, 128 for three dogs and 1024 for one dog. From the seropositive group of dogs, five (83%) of them were males, with their age ranging from 1 to 8 years old. Among the seropositive dogs, four (66.7%) were parasitized with ticks and no breed (or cross) was found to be associated with specific antibodies. Rickettsia spp. DNA was detected by nested-polymerase chain reaction (PCR) in two (1.9%) dogs that were found to be seronegative.
Seroprevalence and molecular detection of Rickettsia spp. infection in this group of pet dogs from Luanda is low compared with other studies performed in the same type of hosts in other areas. Although many dogs were parasitized with ticks, a low prevalence of Rickettsia spp. could be related with the hypothesis of a low rickettsial prevalence in the infesting ticks. This study provides evidence that dogs in Luanda are exposed to Rickettsia spp., but further studies are needed to better characterize the bacterial infections in dogs and in their ectoparasites.
蜱传立克次体感染可引发人类熟知的疾病，但在犬类中仍未得到充分表征。感染易感性取决于立克次体属的毒力，仅有少数几种被描述可在犬类中致病。本研究旨在调查安哥拉罗安达一组宠物犬中立克次体属的暴露情况。
在纳入研究的103只犬中，62只（60.2%）感染了蜱虫。通过免疫荧光测定（IFA）进行血清学检测的血浆样本显示，6只（5.8%）犬具有针对斑点热群立克次体（SFGR）的可检测免疫球蛋白G（IgG）抗体，其中2只犬的终点滴度为64，3只犬为128，1只犬为1024。在血清阳性犬组中，5只（83%）为雄性，年龄在1至8岁之间。在血清阳性犬中，4只（66.7%）感染了蜱虫，未发现特定品种（或杂交品种）与特定抗体相关。通过巢式聚合酶链反应（PCR）在2只（1.9%）血清阴性的犬中检测到立克次体属DNA。
与在其他地区对同一类型宿主进行的其他研究相比，罗安达这组宠物犬中立克次体属感染的血清阳性率和分子检测率较低。尽管许多犬感染了蜱虫，但立克次体属的低流行率可能与感染蜱虫中立克次体流行率低的假设有关。本研究提供了证据表明罗安达的犬暴露于立克次体属，但需要进一步研究以更好地表征犬及其体外寄生虫中的细菌感染情况。
