Dipartimento di Sanità Pubblica e Zootecnia, Università degli Studi di Bari, Valenzano, BA, Italy.
Parasitol Res. 2010 Mar;106(4):857-60. doi: 10.1007/s00436-010-1722-4. Epub 2010 Feb 3.
Canine leishmaniosis is a widespread disease caused by Leishmania parasites, which are transmitted by phlebotomine sand flies. However, in some areas where canine leishmaniosis is endemic, but the primary vectors have not been found, ticks have been suspected to play a role in transmitting the infection. Herewith, we report the detection of Leishmania infantum kinetoplast minicircle DNA (kDNA) in ticks collected from naturally infected dogs living in rural areas of Southern Italy (site A) and Northeastern Brazil (site B). Between March and October 2007, ticks were collected from 26 dogs positive to anti-Leishmania antibodies (one from site A and 25 from site B) and either placed directly into vials containing 70% ethanol or maintained alive for identification and subsequent dissection. All the 95 ticks collected were morphologically identified as Rhipicephalus sanguineus. After identification, their genomic DNA was extracted (either individually or in pools) and processed by polymerase chain reaction (PCR) for the detection of L. infantum kDNA. Two pools of salivary glands from ticks (one from five females and other from five males) found on a dog from site A and tested by a conventional PCR were positive. Amplicon sequencing confirmed the identity of the parasite. In addition, nine (12.3%) out of the 73 ticks found on dogs from site B and tested by a real-time PCR were positive, with a low parasite load (less than 1 parasite/ml). The retrieval of L. infantum kDNA in salivary glands of R. sanguineus ticks has been here reported for the first time. Therefore, further studies are needed to assess the competence of ticks as vectors of Leishmania parasites from dog to dog.
犬利什曼病是一种由利什曼原虫引起的广泛疾病，由沙蝇属的白蛉传播。然而，在一些犬利什曼病流行的地区，尚未发现主要传播媒介，但蜱虫已被怀疑在传播感染方面发挥作用。在此，我们报告了在意大利南部（A 点）和巴西东北部（B 点）自然感染犬中采集的蜱虫中检测到利什曼原虫动基体微环 DNA（kDNA）。2007 年 3 月至 10 月期间，从 26 只抗利什曼原虫抗体阳性的犬（A 点 1 只，B 点 25 只）中采集蜱虫，要么直接放入含有 70%乙醇的小瓶中，要么保持活体状态进行鉴定和随后的解剖。共采集到 95 只蜱虫，形态学上鉴定为血红扇头蜱。鉴定后，提取其基因组 DNA（单独或混合提取），并通过聚合酶链反应（PCR）检测 L. infantum kDNA。对 A 点一只犬身上采集的五雌五雄唾液腺混合的两个蜱虫池（一组来自 5 只雌性，另一组来自 5 只雄性）进行了常规 PCR 检测，结果均为阳性。扩增子测序证实了寄生虫的身份。此外，B 点 73 只犬身上采集的蜱虫，通过实时 PCR 检测，有 9 只（12.3%）为阳性，寄生虫载量较低（低于 1 个寄生虫/ml）。这是首次报道在血红扇头蜱的唾液腺中检测到利什曼原虫 kDNA。因此，需要进一步研究来评估蜱虫作为犬源利什曼原虫传播媒介的能力。
