ABSTRACT
The aim of this study was to evaluate the specificity of a rapid immunochromatographic test that was developed to detect antibodies against the rK39 antigen for the diagnosis of visceral leishmaniasis (VL). This evaluation was performed using sera from patients with a confirmed diagnosis of active cutaneous leishmaniasis. The sera from 272 patients with a confirmed diagnosis of localised cutaneous leishmaniasis (CL) who resided in an area endemic for Leishmania braziliensis in Brazil were obtained before the initiation of antileishmanial treatment. Kalazar Detect(r)(InBios, Seattle, WA) recombinant K39 antigen-based immunochromatographic strips were used according to the manufacturer's instructions. The test results were evaluated independently by two examiners in sequential order. The positive controls for the test included five serum samples from five patients with parasitologically confirmed diagnosis of VL caused by Leishmania infantum in Brazil. Overall, 100% of the samples obtained from patients with CL were negative, confirming the absence of a serological cross-reaction for individuals with cutaneous disease when these patients were evaluated using the rapid test. The lack of a cross-reaction in patients who were infected by parasites of the same genus highlights the specificity of the rK39 antigen for the diagnosis of VL in areas with the sympatric circulation of L. braziliensis and L. infantum.
Subject(s)
Adolescent , Adult , Child , Female , Humans , Male , Middle Aged , Young Adult , Antigens, Protozoan , Leishmania braziliensis/immunology , Leishmaniasis, Cutaneous/diagnosis , Protozoan Proteins , Chromatography, Affinity , Leishmaniasis, Cutaneous/immunology , Reagent Kits, Diagnostic , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
Un estudio transversal fue desarrollado para evaluar la seroprevalencia de la leishmaniasis visceral zoonótica y la tripanosomiasis americana en 211 caninos mestizos de una zona endémica para los dos protozoarios en el sur del departamento del Tolima. Los anticuerpos séricos anti-Leishmania infantum y anti-Trypanosoma cruzi fueron determinados por medio de las técnicas ELISA y Western Blot, usando los antígenos recombinantes rK39 y TESA, respectivamente. Se realizó xenodiagnóstico a los animales seropositivos a T. cruzi. De acuerdo con los resultados, el 40,28% (85/211) y el 1,42% (3/211) de los caninos presentaron anticuerpos contra L. infantum y T. cruzi, respectivamente. El xenodiagnóstico fue negativo. Los resultados sugieren que los caninos pueden jugar un papel importante como reservorios de L. infantum y fuentes de infección para la población infantil del área de estudio. Sin embargo, los perros podrían tener un papel limitado en la transmisión de T. cruzi. Se hace necesario contar con un algoritmo de pruebas diagnósticas para confirmar el estado real de la infección de los animales y para establecer la presencia de reacciones cruzadas o coinfecciones.
A cross-sectional study was conducted in order to evaluate the seroprevalence of zoonotic visceral Leishmaniasis and American Trypanosomiasis in 211 mongrel dogs from an endemic area for the two protozoans in southern Tolima. Serum anti-Leishmania infantum and anti-Trypanosoma cruzi antibodies were determined by ELISA and Western Blot techniques, using rK39 and TESA recombinant antigens respectively. The Xenodiagnosis was performed on the seropositive to T. cruzi. According to the results, 40.28% (85/211) and 1.42% (3/211) of the dogs tested positive for antibodies against L. infantum and T. cruzi respectively. The Xenodiagnosis was negative. The results suggest that dogs may play an important role as reservoirs of L. infantum and infection sources for children in the study area. However, dogs may play a limited role in the transmission of T. cruzi. It is necessary to have an algorithm for diagnostic tests to confirm the actual status of the animals infection and to establish the presence of cross-reactions or co-infections.