Laboratory of Applied Preventive Veterinary Medicine, Department of Veterinary Medicine, Faculty of Animal Science and Food Engineering, University of São Paulo - USP, Pirassununga, São Paulo, Brazil; Postgraduate Program in Experimental Epidemiology Applied to Zoonoses, Department of Preventive Veterinary Medicine and Animal Health, Faculty of Veterinary Medicine and Animal Science, University of São Paulo - USP, Pirassununga, São Paulo, Brazil.
Laboratory of Applied Preventive Veterinary Medicine, Department of Veterinary Medicine, Faculty of Animal Science and Food Engineering, University of São Paulo - USP, Pirassununga, São Paulo, Brazil; Department of Veterinary Medicine, Faculty of Food Engineering and Animal Science, University of São Paulo - USP, Pirassununga, São Paulo, Brazil.
Exp Parasitol. 2022 Aug;239:108294. doi: 10.1016/j.exppara.2022.108294. Epub 2022 Jun 6.
This study evaluated the humoral and cellular response in 100 cats living in an endemic area of visceral leishmaniosis (VL) using the Montenegro Skin Test (MST) and serological diagnosis and compared the MST with other diagnostic techniques. Sixty 60%, (60/100) cats were positive for MST and the diameter of positive skin reactions ranged from 5 to 9 mm. By serological methods, 74% (74/100) and 34% (34/100) had antibodies against Leishmania spp. by Immunofluorescence Antibody Test (IFAT) and Indirect Enzyme-Linked Immunosorbent Assay (ELISA), respectively. Comparing tests, the observed profiles were (1) IFAT (+)/MST (-) = 27 cats, (2) IFAT(-)/MST(+) = 13 cats, (3) IFAT(+)/MST(+) = 47 cats, (4) ELISA(+)/MST(-) = 12 cats, (5) ELISA(-)/MST(+) = 38 cats and (6) ELISA(+)/MST(+) = 22 cats. Through the combination of serological diagnosis and MST, a positivity frequency of 87% (87/100) by IFAT + MST and 72% (72/100) by ELISA + MST was identified in this cat population. Five cats (5%) were positive for Leishmania donovani complex DNA by molecular analysis, and two cats (2%) had Leishmania spp. amastigotes in lymph node smears. Therefore, the agreement between tests was classified as poor for all tests by Kappa index. The IFAT (+)/MST (+) response was the most frequent considering all cats (47%; 47/100); nonetheless, the most frequent immune expression in Polymerase Chain Reaction (PCR)-positive cats was the IFAT (+)/MST (-) profile (80%; 4/5). Five sick and PCR-positive cats, negative for Feline Immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV), that PCR sequencing matched 100% with L. donovani complex, all but one were MST negative. These results suggest that cats develop a significant cellular response against infection by parasites of the L. donovani complex, and most PCR and parasitological positive cats may be unable to develop a significant cellular response.
本研究评估了 100 只生活在内脏利什曼病（VL）流行地区的猫的体液和细胞反应，使用 Montenegro 皮肤试验（MST）和血清学诊断，并将 MST 与其他诊断技术进行了比较。60%（60/100）的猫对 MST 呈阳性，阳性皮肤反应的直径范围为 5 至 9 毫米。通过血清学方法，74%（74/100）和 34%（34/100）的猫对利什曼原虫 spp.的抗体分别通过免疫荧光抗体试验（IFAT）和间接酶联免疫吸附试验（ELISA）呈阳性。比较试验结果，观察到的结果为：（1）IFAT（+）/MST（-）=27 只猫，（2）IFAT（-）/MST（+）=13 只猫，（3）IFAT（+）/MST（+）=47 只猫，（4）ELISA（+）/MST（-）=12 只猫，（5）ELISA（-）/MST（+）=38 只猫和（6）ELISA（+）/MST（+）=22 只猫。通过血清学诊断和 MST 的联合应用，IFAT + MST 阳性的猫的阳性频率为 87%（87/100），ELISA + MST 阳性的猫的阳性频率为 72%（72/100）。在该猫群中，5 只猫（5%）的利什曼原虫复合体 DNA 通过分子分析呈阳性，2 只猫（2%）的淋巴结涂片中有利什曼原虫无鞭毛体。因此，所有试验的 Kappa 指数均显示试验之间的一致性为差。考虑到所有猫，IFAT（+）/MST（+）的反应是最常见的（47%；47/100）；然而，PCR 阳性猫中最常见的免疫表达是 IFAT（+）/MST（-）图谱（80%；4/5）。5 只患有疾病且 PCR 阳性的猫，Feline Immunodeficiency Virus（FIV）和 Feline Leukemia Virus（FeLV）均为阴性，PCR 测序与利什曼原虫复合体 100%匹配，但只有 1 只 MST 阴性。这些结果表明，猫对利什曼原虫复合体寄生虫的感染产生了显著的细胞反应，大多数 PCR 和寄生虫学阳性的猫可能无法产生显著的细胞反应。
