Grupo de Investigaciones Microbiológicas-UR (GIMUR), Departamento de Biología, Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Bogotá, Colombia.
Grupo de Parasitología, Instituto Nacional de Salud, Bogotá, Colombia.
BMC Infect Dis. 2019 Aug 27;19(1):747. doi: 10.1186/s12879-019-4353-0.
Leishmaniasis caused by different species of Leishmania affect 98 countries worldwide. Visceral Leishmaniasis (VL) is the mortal clinical presentation of the disease that causes the dead to more than 90% of the patients who suffer it. The diagnosis of VL is made by the direct observation of the parasite in bone marrow, spleen and/or liver aspirates that requires complex proceedings. Therefore, serum samples are submitted to Indirect Immunofluorescence to identify the presence of anti-Leishmania antibodies. Despite the variability in the diagnostic performance of the Immunochromatographic Tests (ICTs), there are many evidences that suggest that ICTs can be used for epidemiological screening. However, in Colombia there are not any evidence about the performance of the ICTs for VL diagnosis, both for human and canine serum samples. Therefore, this study evaluated the diagnostic performance of 4 ICTs for VL (2 ICTs in human sera and 2 ICTs in canine sera) in samples from endemic areas of Colombia.
We selected a total of 156 human serum samples (82 positive and 74 negative for VL) and 126 canine serum samples (71 positive and 54 negative) diagnosed by in house Indirect Immunofluorescence (IIF). The samples were submitted to the ICTs following the manufacturers' instructions. Statistical analysis was performed to evaluate the diagnostic performance of each ICT in comparison with the IIF. PCR for HSP70 gene and sanger sequencing was performed in samples with negative results for both ICTs.
The sensitivity (S) of both ICTs for human samples (Ad-bio Leishmania IgG/IgM Combo Rapid Test and Kalazar Detect™) was 91.5% and specificity (E) were 93.2 and 89.2% respectively, while for the ICTs tested on canine samples (Kalazar Detect™ Rapid Test, Canine and DPP® CVL rapid test) we found S values between 82.9 and 85.7% and E values between 79.6 and 92.6%. We found L. infantum by PCR and sequencing in 2 human samples, and L. braziliensis and L. amazonensis in canine serum samples that were negative by both ICTs.
We conclude that both tests evaluated on human samples have a similar diagnostic performance, while the Kalazar Detect™ Rapid Test, Canine showed a better diagnostic performance than the DPP® CVL rapid test evaluated on canine samples. Also, we suggest that it is necessary to design tests with antigens of the circulating strains to increase its diagnostic utility.
由不同种利什曼原虫引起的利什曼病影响全球 98 个国家。内脏利什曼病（VL）是该病的致命临床表现，导致 90%以上的患者死亡。VL 的诊断是通过直接观察骨髓、脾脏和/或肝脏抽吸物中的寄生虫来进行的，这需要复杂的程序。因此，血清样本被提交给间接免疫荧光以识别抗利什曼原虫抗体的存在。尽管免疫层析检测（ICTs）的诊断性能存在差异，但有许多证据表明 ICTs 可用于流行病学筛查。然而，在哥伦比亚，尚无关于 ICTs 用于 VL 诊断的人类和犬血清样本的性能的任何证据。因此，本研究评估了 4 种 ICTs（2 种用于人血清，2 种用于犬血清）在哥伦比亚疫区样本中的诊断性能。
我们选择了总共 156 个人类血清样本（82 个 VL 阳性，74 个 VL 阴性）和 126 个犬血清样本（71 个阳性，54 个阴性），这些样本通过内部间接免疫荧光（IIF）进行了诊断。根据制造商的说明，将样本提交给 ICTs。进行了统计分析，以评估与 IIF 相比，每种 ICT 的诊断性能。在两种 ICT 均为阴性的样本中进行 HSP70 基因 PCR 和 Sanger 测序。
两种用于人类样本的 ICT（Ad-bio Leishmania IgG/IgM Combo Rapid Test 和 Kalazar Detect™）的敏感性（S）分别为 91.5%和特异性（E）分别为 93.2%和 89.2%，而用于犬血清样本的 ICT（Kalazar Detect™ Rapid Test、Canine 和 DPP® CVL rapid test）的 S 值在 82.9%至 85.7%之间，E 值在 79.6%至 92.6%之间。我们通过 PCR 和测序在 2 个人类样本中发现了 L. infantum，在两种 ICT 均为阴性的犬血清样本中发现了 L. braziliensis 和 L. amazonensis。
我们得出结论，两种在人类样本中评估的测试具有相似的诊断性能，而 Kalazar Detect™ Rapid Test、Canine 在犬血清样本中的诊断性能优于评估的 DPP® CVL rapid test。此外，我们建议设计具有循环株抗原的检测，以提高其诊断效用。
