Autochthonous canine visceral leishmaniasis cases occur in Paraná state since 2012: isolation and identification of Leishmania infantum

Abstract The aim of this study was to confirm the emergence of canine visceral leishmaniasis among dogs in Foz do Iguaçu. The disease was diagnosed through the isolation and molecular identification of Leishmania infantum. In the first sample collection stage (2012), three lymph node aspirates and 46 buffy coat samples were obtained mostly from the dogs that were seroreagents for leishmaniasis. In the second sample collection stage (2013), the buffy coat samples were collected from 376 dogs located close to Paraguay, Paraná river, center and peripheral parts of the city. The DNA from the six isolates, four from the first sampling stage (4/49) and two from the second sampling stage (2/376), was subjected to polymerase chain reaction using the K26F/R primers. The isolate was confirmed as L. infantum by sequencing. As none of the dogs had ever left the city, the isolates were confirmed as autochthonous. Further, the study confirmed the emergence of canine visceral leishmaniasis in Paraná through the identification of L. infantum among dogs in Foz do Iguaçu city. Hence, collaborative control measures should be designed and implemented by the public agencies and research institutions of Brazil, Argentina, and Paraguay to control the spread of visceral leishmaniasis.

摘要 本研究旨在确认伊瓜苏市（Foz do Iguaçu）犬群中犬内脏利什曼病（canine visceral leishmaniasis）的暴发情况。本研究通过分离并分子鉴定婴儿利什曼原虫（Leishmania infantum）完成该病的确诊。在第一阶段采样工作（2012年）中，研究人员主要从利什曼病血清学反应阳性的犬只体内采集了3份淋巴结穿刺液样本与46份棕黄层（buffy coat）样本。第二阶段采样工作（2013年）则从毗邻巴拉圭、巴拉那河（Paraná River）的伊瓜苏市城区中心与城郊区域的376只犬只体内采集了棕黄层样本。研究人员对6株分离株的DNA进行聚合酶链式反应（polymerase chain reaction，PCR）扩增，其中4株来自第一阶段采样样本（4/49），2株来自第二阶段采样样本（2/376），所用引物为K26F/R。经测序确认该分离株为婴儿利什曼原虫。由于所有受试犬只均未离开过伊瓜苏市，故确认该分离株为本地源性分离株。此外，本研究通过在伊瓜苏市犬群中鉴定出婴儿利什曼原虫，证实了巴拉那州（Paraná）境内存在犬内脏利什曼病的暴发。因此，巴西、阿根廷与巴拉圭的公共机构及科研机构应协同制定并实施防控措施，以遏制内脏利什曼病的传播。