Polymerase chain reaction and real-time PCR for diagnosing of Leishmania infantum chagasi in dogs

Rafael Antonio do Nascimento Ramos,Rosangela Zacarias Machado,Flábio Ribeiro de Araújo,Leucio Câmara Alves,Maria Aparecida da Glória Faustino,Márcia Mariza Gomes Jusi,Carlos Alberto do Nascimento Ramos

doi:10.1590/s1984-29612012000300003

Abstract

The importance of dogs as a reservoir for Leishmania infantumchagasi in urban environments has stimulated numerous studies assessing diagnostic techniques. When performed properly, such procedures are an important step in preventing leishmaniasis in humans. Molecular methods have become prominent for this purpose. The aim of the present study was to determine the performance of the polymerase chain reaction (PCR) and real-time PCR (qPCR) for diagnosing of canine visceral leishmaniasis (CVL) using different biological samples. For this, 35 dogs from an area endemic for CVL were used. Bone marrow aspirate and lymph node and spleen fragments from these dogs were used for the molecular diagnosis. In the present study, qPCR was able to detect a greater number of positive animals than seen with PCR. Among the different biological samples used, there was no significant difference in L. infantumchagasi DNA detection between PCR and qPCR. However, considering that lymph nodes are easy to acquire, these can be considered to be the best samples for making molecular diagnoses of L. infantum chagasi infection.

Highlights

Diagnosing for canine visceral leishmaniasis (CVL) in dogs is a challenge in routine veterinary practice
Among the different biological samples used, there was no significant difference in L. infantum chagasi DNA detection between polymerase chain reaction (PCR) and qPCR
From the PCR tests, DNA of L. infantum chagasi was detected in 40% (14/35) of the animals

Summary

Introduction

Diagnosing for canine visceral leishmaniasis (CVL) in dogs is a challenge in routine veterinary practice. Depending on the stage of the disease and immunological conditions, animals may be asymptomatic (TASCA et al, 2009), which makes the correct diagnosis more difficult. Parasitological techniques are used for diagnosing this disease (BARROUIN-MELO et al, 2006), but these methods have some limitations, such as, a low degree of sensitivity (PIARROUX et al, 1994). Culturing of Leishmania cells and xenodiagnosis, are used. These techniques are time-consuming, has low sensitivity, and the latter is little used in routine diagnosis (PIARROUX et al, 1994)

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