Avaliação do teste rápido Sandfly para infecção natural por Leishmania em flebotomíneos / Rapid test evaluation Sandfly to natural infection by Leishmania in sand flies

RESUMO

Este trabalho buscou avaliar a eficiência do teste rápido SandFly em campo, tendo a PCR como padrão ouro. As coletas e a realização dos testes se deram na Ilha da Marambaia, Estado do Rio de Janeiro, que possui registros de LTA em humanos e LVC. As capturas de flebotomíneos ocorreram utilizando armadilhas luminosas do tipo CDC, que funcionaram entre 1900 hr e 700 hr da manhã seguinte, durante 2 meses consecutivos, Setembro e Outubro de 2014, totalizando 8 coletas em 5 áreas distintas. No total, foram coletados 1505 espécimes de flebotomíneos. Para o diagnóstico de infecção, as fêmeas de cada coleta foram escolhidas ao acaso e separadas em pools de dez; cada pool foi macerado com o tampão de lise e metade de cada amostra foi utilizada nos testes; a outra metade foi encaminhada para realização da PCR. O restante dos flebotomíneos foi encaminhado para identificação de espécies. Nos TRs, 4 resultados foram positivos, 1 em Setembro (amostra A13) e 3 em Outubro (B11, B13 e B14) nos 49 pools analisados, todos sendo fracos. O diagnóstico pela PCR revelou infecção natural por Leishmania em flebotomíneos de 3 áreas na Ilha de Marambaia Praia Grande, Praia de São José e Praia da Cutuca 7 resultados positivos (A13, A17, A18, A19, A22, A23 e A24) nas 29 amostras de Setembro e 7 resultados positivos (B01, B02, B05, B06, B09, B13 e B17) nas 19 amostras com fêmeas de Outubro, totalizando 14 resultados positivos. Comparando ao padrão ouro, dos 49 testes realizados 2 revelaram ser verdadeiros positivos, 33 verdadeiros negativos, 2 falsos positivos e 12 falsos negativos.

ABSTRACT

This study aimed to evaluate the efficiency of the Sandfly rapid test in the field considering the PCR as the gold standard. The collections and the tests were performed in Marambaia Island (State of Rio de Janeiro) that has records of Tegumentar Leishmaniasis in humans and Visceral Leishmaniasis in dogs. The collections were performed using CDC light traps from 7 pm to 7 am, for 2 consecutive months - September and October 2014, totaling 8 collections in 5 different areas. A total of 1505 sandflies were collected. Females of each collection were chosen at random and stored in labeled pools of 10 specimens. Each pool was macerated with lysis buffer solution and half of each sample was used in the tests; the other half of the samples was referred for evaluation of infection by Leishmania spp. through PCR. The remaining sandflies were sent for species identification. 4 rapid test results were positive - 1 September (sample A13) and 3 October (B11, B13 and B14) in the 49 analyzed pools and all were weak. Diagnosis by PCR revealed Leishmania natural infection in 3 areas in Marambaia Island Praia Grande, Praia de São José and Praia da Cutuca. It was 7 positive results (A13, A17, A18, A19, A22, A23 and A24) in 29 samples of September and 7 positive results (B01, B02, B05, B06, B09, B13 and B17) in 19 samples with October females, totaling 14 positive results. Considering PCR as the gold standard, 2 rapid tests results were evaluated as true positives, 33 as true negative, 2 as false positives and 12 as false negatives. Some calculations were performed to evaluate the rapid test efficiency compared to PCR. The relative sensitivity was 14 percent and the relative specificity was 94.2 percent. The Positive Predictive Value was PPV = 0.50 while the Negative Predictive Value was 0.73. The accuracy was 0.71.