Laboratoire de Virus, Vecteurs et Hôtes: LR20IPT02, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis-Belvédère, Tunisia.
One Health Institute, University of California, Davis, Davis, California, United States of America.
PLoS Negl Trop Dis. 2021 Dec 10;15(12):e0009990. doi: 10.1371/journal.pntd.0009990. eCollection 2021 Dec.
Discovered by Nicolle and Comte in 1908 in Tunisia, Leishmania infantum is an intracellular protozoan responsible for zoonotic canine leishmaniosis (CanL) and zoonotic human visceral leishmaniasis (HVL). It is endemic in several regions of the world, including Tunisia, with dogs considered as the main domestic reservoir. The geographic expansion of canine leishmaniosis (CanL) has been linked to global environmental changes that have affected the density and the distribution of its sand fly vectors.
METHODOLOGY/PRINCIPAL FINDINGS: In this study, a cross-sectional epidemiological survey on CanL was carried out in 8 localities in 8 bioclimatic areas of Tunisia. Blood samples were taken from 317 dogs after clinical examination. Collected sera were tested by indirect fluorescent antibody test (IFAT; 1:80) for the presence of anti-Leishmania infantum antibodies. The overall seroprevalence was 58.3% (185/317). Among positive dogs, only 16.7% showed clinical signs suggestive of leishmaniosis. Seroprevalence rates varied from 6.8% to 84.6% and from 28% to 66% by bioclimatic zone and age group, respectively. Serological positivity was not statistically associated with gender. The presence of Leishmania DNA in blood, using PCR, revealed 21.2% (64/302) prevalence in dogs, which varied by bioclimatic zone (7.3% to 31%) and age group (7% to 25%). The entomological survey carried out in the studied localities showed 16 species of the two genera (Phlebotomus and Sergentomyia). P. perniciosus, P. papatasi, and P. perfiliewi were the most dominant species with relative abundances of 34.7%, 25% and 20.4%, respectively.
CONCLUSIONS/SIGNIFICANCE: The present report suggests a significant increase of CanL in all bioclimatic areas in Tunisia and confirms the ongoing spread of the infection of dogs to the country's arid zone. Such an expansion of infection in dog population could be attributed to ecological, agronomic, social and climatic factors that affect the presence and density of the phlebotomine vectors.
1908 年，Nicolle 和 Comte 在突尼斯发现了利什曼原虫，这是一种引起动物源性犬利什曼病（CanL）和动物源性人类内脏利什曼病（HVL）的细胞内原生动物。它在包括突尼斯在内的世界多个地区流行，犬被认为是主要的家养宿主。犬利什曼病（CanL）的地理扩张与影响其沙蝇媒介密度和分布的全球环境变化有关。
方法/主要发现：在这项研究中，对突尼斯 8 个生物气候区的 8 个地区进行了犬利什曼病的横断面流行病学调查。对 317 只经过临床检查的犬采集了血液样本。采集的血清用间接荧光抗体试验（IFAT；1:80）检测抗利什曼原虫抗体的存在情况。总血清阳性率为 58.3%（185/317）。在阳性犬中，只有 16.7%表现出提示利什曼病的临床症状。血清阳性率按生物气候区和年龄组分别为 6.8%至 84.6%和 28%至 66%。血清学阳性与性别无统计学关联。用 PCR 检测血液中的利什曼原虫 DNA，显示犬的阳性率为 21.2%（64/302），按生物气候区（7.3%至 31%）和年龄组（7%至 25%）而有所不同。在研究地区进行的昆虫学调查显示，有两种属（白蛉和塞氏蝇）的 16 种。其中，P. perniciosus、P. papatasi 和 P. perfiliewi 是最主要的物种，相对丰度分别为 34.7%、25%和 20.4%。
结论/意义：本报告表明，突尼斯所有生物气候区的犬利什曼病都有显著增加，并证实了该感染正在向该国的干旱地区蔓延。这种犬群感染的扩大可能归因于影响白蛉媒介存在和密度的生态、农业、社会和气候因素。
