Evaluation of the performance of three serological tests for diagnosis of Leishmania infantum infection in dogs using latent class analysis / Avaliação da realização de três testes sorológicos para diagnóstico de infecção por Leishmania infantum em cães utilizando análise de classe latente

Abstract Canine leishmaniasis (CanL) is a disease caused by Leishmania infantum. Serological methods are the most common diagnostic techniques used for the diagnosis of the CanL. The objective of our study was to estimate the sensitivity and specificity of one in-house ELISA kit (ELISA UNIZAR) and three commercially available serological tests (MEGACOR Diagnostik GmbH) including an immunochromatographic rapid test (FASTest LEISH®), an immunofluorescent antibody test (MegaFLUO LEISH®) and an enzyme-linked immunosorbent assay (MegaELISA LEISH®), using latent class models in a Bayesian analysis. Two hundred fifteen serum samples were included. The highest sensitivity was achieved for FASTest LEISH® (99.38%), ELISA UNIZAR (99.37%), MegaFLUO LEISH® (99.36%) followed by MegaELISA LEISH® (98.49%). The best specificity was obtained by FASTest LEISH® (98.43%), followed by ELISA UNIZAR (97.50%), whilst MegaFLUO LEISH® and MegaELISA LEISH® obtained the lower specificity (91.94% and 91.93%, respectively). The results of present study indicate that the immunochromatographic rapid test evaluated FASTest LEISH® show similar levels of sensitivity and specificity to the quantitative commercial tests. Among quantitative serological tests, sensitivity and specificity were similar considering ELISA or IFAT techniques.

Resumo A leishmaniose canina (Lcan) é uma causada pela Leishmania infantum. Os métodos sorológicos são as técnicas diagnósticas mais utilizadas para o diagnóstico da leishmaniose canina. O objetivo do nosso estudo foi estimar a sensibilidade e a especificidade de um kit ELISA interno (ELISA UNIZAR) e de três testes sorológicos disponíveis comercialmente, feitos pelo mesmo fabricante (MEGACOR Diagnostik GmbH), incluindo um teste rápido imunocromatográfico (FASTest LEISH®), um teste de anticorpos imunofluorescentes (Megafluo LEISH®) e um ensaio de imunoabsorção enzimática (Megaelisa LEISH®), utilizando-se modelos de classe latentes numa análise bayesiana. Foram incluídas duzentas e quinze amostras de soro. A maior sensibilidade foi alcançada para Fastest LEISH® (99,38%), ELISA UNIZAR (99,37%), Megafluo LEISH® (99,36%) seguida por Megaelisa LEISH® (98,49%). A melhor especificidade foi obtida por FASTest LEISH® (98,43%), seguida por ELISA UNIZAR (97,50%), enquanto Megafluo LEISH® e Megaelisa LEISH® obtiveram a menor especificidade (91,94% e 91,93%, respectivamente). Os resultados do presente estudo indicam que o teste rápido imunocromatográfico, avaliado por FASTest LEISH® mostra níveis similares de sensibilidade e especificidade aos testes comerciais quantitativos incluídos. Entre os testes sorológicos quantitativos, a sensibilidade e a especificidade foram semelhantes, considerando-se as técnicas de ELISA ou IFI.

Effect of oral administration of Propionibacterium acnes on growth performance, DTH response and anti-OVA titers in goat kids

Immunostimulants are susbstances that stimuli the response of effector cells to activate the immune response such as antigen uptake, cytokine release or antibody response. These substances can increase resistence to infection by different types of microorganisms, reducing dependence of antibiotics used in livestock animals. Recent reports have demonstrated the positive effect of Propionibacterium acnes (P. acnes) to control animal diseases. In this study, we evaluated the effect of the non-specific immunostimulant P. acnes on immunological functions and growth performance in goat kids. Twenty five goat kids served as control group (A) and another 25 animals received P. acnes being the experimental group (B). Kids were challenged with ovalbumin (OVA) to assess humoral immunity. To assess in vivo cell immunity, delayed type hypersensitivity (DTH) test with phytohemagglutinin (PHA) was used, clinical signs and body weight were recorded each week until 9 weeks of age when the experiment ended. Blood samples were obtained to analyze serum proteins fractions and anti-OVA specific antibodies. No clinical signs of disease and no differences (p>0.05) on body weight between groups were recorded (7.32±0.81 kg in group A, 7.13±0.65 kg in group B). Goat kids from group B had more total protein (59.8±5g/l) and albumin levels (32.8±3.3g/l) than goat kids from group A (56.6±5.7 g/l, 29.6±3.9 g/l respectively) (p<0.05). DTH response in goat kids from group B on day 42 was higher (p<0.05) than group A. At day 63, goat kids from group receiving P. acnes had higher percentage (85.4) of anti-OVA IgM titers (p<0.05) than control group (57.7). In conclusion, the results showed that oral administration of P. acnes to goat kids improved some aspects of the immune system of the animals and it could be used to control goat diseases.