Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil.
Departamento de Moléstias Infecciosas e Parasitárias, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil.
Parasitol Res. 2022 Sep;121(9):2683-2695. doi: 10.1007/s00436-022-07594-5. Epub 2022 Jul 8.
The parasitic protozoa Leishmania (Leishmania) infantum is the etiological agent of human visceral leishmaniasis and canine leishmaniasis in South America, where Brazil is the most affected country. This zoonotic disease is transmitted by the bite of an infected phlebotomine sand fly and dogs constitute the main domestic reservoir of the parasite. In this study, we screened 2348 dogs of the municipality of Embu das Artes, Brazil, for antibodies against the parasite. Prevalence for canine leishmaniasis seropositivity was 2.81%, as assessed using a Dual-Path Platform rapid test for canine leishmaniasis. Twenty-five seropositive dogs were euthanized for parasite isolation and 14 isolates were successful obtained. Nucleotide sequencing of the internal transcribed spacer confirmed the isolates to be L. (L.) infantum, and very low sequence variability was observed among them. The in vitro susceptibility to miltefosine and paromomycin was assessed and moderate variation in paromomycin susceptibility was found among the isolates in the promastigote and intracellular amastigote stages. On the other hand, in vitro susceptibility to miltefosine of these isolates was homogenous, particularly in the amastigote stage (EC values from 0.69 to 2.07 μM). In addition, the miltefosine sensitivity locus was deleted in all the isolates, which does not corroborate the hypothesis that the absence of this locus is correlated with a low in vitro susceptibility. Our findings confirm that the municipality of Embu das Artes is endemic for canine leishmaniasis and that isolates from this region are susceptible to paromomycin and miltefosine, indicating the potential of these drugs to be clinically evaluated in the treatment of human visceral leishmaniasis in Brazil.
寄生原生动物利什曼原虫（Leishmania）婴儿是南美的人类内脏利什曼病和犬利什曼病的病原体，巴西是受影响最严重的国家。这种人畜共患病通过受感染的白蛉沙蝇叮咬传播，狗是寄生虫的主要家养宿主。在这项研究中，我们对巴西恩布达斯阿尔特斯市的 2348 只狗进行了针对寄生虫的抗体筛查。使用双路径平台快速检测犬利什曼病，评估犬利什曼病血清阳性率为 2.81%。25 只血清阳性犬被安乐死以分离寄生虫，成功获得 14 个分离株。内部转录间隔区的核苷酸测序证实这些分离株为 L.（L.）婴儿，并观察到它们之间的序列变异性非常低。评估了米替福新和巴龙霉素对分离株的体外敏感性，发现这些分离株在原虫和细胞内无鞭毛体阶段对巴龙霉素的敏感性存在适度差异。另一方面，这些分离株对米替福新的体外敏感性是同质的，特别是在无鞭毛体阶段（EC 值为 0.69 至 2.07 μM）。此外，所有分离株均缺失米替福新敏感性基因座，这与该基因座缺失与体外低敏感性相关的假设不符。我们的研究结果证实，恩布达斯阿尔特斯市存在犬利什曼病地方性流行，并且该地区的分离株对巴龙霉素和米替福新敏感，这表明这些药物具有在巴西治疗人类内脏利什曼病的临床评估潜力。
