Evaluación de una prueba de aglutinación directa como método alternativo para el diagnóstico de leishmaniasis visceral canina y humana en Venezuela / The direct agglutination test as an alternative method for the diagnosis of canine and human visceral leishmaniasis

RESUMEN

Introduction. Visceral leishmaniasis is the most severe clinical form of leishmaniasis and is often fatal without proper treatment. Therefore, early and accurate diagnosis is important, but often difficult in endemic areas. Objective. The aim was to evaluate a direct agglutination test as a potential visceral leishmaniasis diagnostic method in endemic areas of Venezuela Materials and methods. The performance of the direct agglutination test, based on freezedried Leishmania donovani antigen was evaluated under laboratory conditions using serum samples of humans and dogs from several Venezuelan visceral leishmaniasis endemic areas Nueva Esparta (Margarita Island), Lara, Anzoátegui and Trujillo Status. The study included confirmed visceral leishmaniasis patients (n=30), visceral leishmaniasis suspected subjects (n=4), healthy controls (n=19) and patients with other confirmed diseases (n=20). In addition, 24 serum samples from dogs with confirmed visceral leishmaniasis and 18 healthy control dogs were tested. Results. All serum samples of visceral leishmaniasis patients, either active or recovered, were positive. They showed anti- L. donovani titers above 11600. Three out of four suspected visceral leishmaniasis cases were also positive, while serum samples from endemic controls and patients with other diseases had titers lower than 1800. A sensitivity of 100 percent was obtained for all threshold levels under consideration and 100 percent specificity at the threshold titer of 1800 (95 percent confidence interval 91-100 percent). A 93 percent sensitivity (95 percent confidence interval 76-99 percent) was observed in dog samples, with 100 percent specificity (95 percent confidence interval 79-100 percent) at the threshold titer of 1200. Conclusion. The direct agglutination test seems suitable for use in epidemiological studies and for serological diagnosis of human visceral leishmaniasis and canine visceral leishmaniasis.