Centro de Pesquisa Gonçalo Moniz, FIOCRUZ-BA, Bahia, Brazil.
PLoS One. 2013;8(4):e60535. doi: 10.1371/journal.pone.0060535. Epub 2013 Apr 5.
Canine Visceral Leishmaniasis (CVL) is a zoonotic disease caused by Leishmania infantum, transmitted by the bite of Lutzomyia longipalpis sand flies. Dogs are the main domestic reservoir of the parasite. The establishment of an experimental model that partially reproduces natural infection in dogs is very important to test vaccine candidates, mainly regarding those that use salivary proteins from the vector and new therapeutical approaches.
METHODOLOGY/PRINCIPAL FINDINGS: In this report, we describe an experimental infection in dogs, using intradermal injection of Leishmania infantum plus salivary gland homogenate (SGH) of Lutzomyia longipalpis. Thirty-five dogs were infected with 1×10(7) parasites combined with five pairs of Lutzomyia longipalpis salivary glands and followed for 450 days after infection and clinical, immunological and parasitological parameters were evaluated. Two hundred and ten days after infection we observed that 31,4% of dogs did not display detectable levels of anti-Leishmania antibodies but all presented different numbers of parasites in the lymph nodes. Animals with a positive xenodiagnosis had at least 3,35×10(5) parasites in their lymph nodes. An increase of IFN-γ and IL-10 levels was detected during infection. Twenty two percent of dogs developed symptoms of CVL during infection.
The infection model described here shows some degree of similarity when compared with naturally infected dogs opening new perspectives for the study of CVL using an experimental model that employs the combination of parasites and sand fly saliva both present during natural transmission.
犬内脏利什曼病（CVL）是一种由利什曼原虫引起的人畜共患病，通过长舌蝇的叮咬传播。狗是寄生虫的主要家养宿主。建立一种能够部分重现自然感染的实验模型对于测试疫苗候选物非常重要，特别是那些利用媒介唾液蛋白和新治疗方法的候选物。
方法/主要发现：在本报告中，我们描述了一种使用利什曼原虫加长舌蝇唾液腺匀浆（SGH）皮内注射的犬实验感染。35 只狗感染了 1×10(7)个寄生虫，同时感染了五对长舌蝇唾液腺，并在感染后 450 天进行了临床、免疫学和寄生虫学参数评估。感染后 210 天，我们观察到 31.4%的狗没有检测到抗利什曼原虫抗体，但所有狗的淋巴结中都有不同数量的寄生虫。经异种诊断阳性的动物淋巴结中的寄生虫至少有 3.35×10(5)个。感染过程中检测到 IFN-γ和 IL-10 水平的增加。22%的狗在感染过程中出现了 CVL 的症状。
与自然感染的狗相比，这里描述的感染模型显示出一定程度的相似性，为使用实验模型研究 CVL 开辟了新的前景，该模型采用寄生虫和沙蝇唾液的组合，这些在自然传播过程中都存在。
