Leishmania infantum-Derived Glycoinositolphospholipids in the Immunodiagnosis of Subclinically Infected Dogs.

Julia Ramos Sampaio,Thiago Doria Barral,Gabriela Porfirio Passos,Rodrigo Pedro Soares,Ricardo Wagner Portela,Stella Maria Barrouin-Melo,Roberto Meyer,Maisa Santos Fonseca

doi:10.3389/fvets.2021.581148

Julia Ramos Sampaio, Thiago Doria Barral + Show 6 more

Open Access

https://doi.org/10.3389/fvets.2021.581148

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Abstract

Lipophosphoglycan (LPG), when used as an ELISA target, confers high specificity and sensitivity to the detection of Leishmania infantum antibodies in dogs. Glycoconjugates are economically viable because the yield is very high after extraction/purification. In addition, they are very stable, which allows their use in point-of-care testing without special storage conditions. During the glycoconjugate extraction, a glycoinositolphospholipid (GIPL)-enriched fraction is obtained in similar quantities as LPG. Since GIPLs can be extracted from the same parasite pellet as LPGs, this work aimed to evaluate the immune recognition of GIPLs by Leishmania infantum-infected dogs and its use for canine leishmaniasis (CanL) immunodiagnosis. Like LPG, GIPLs were recognized by sera from L. infantum-infected dogs, but with less sensitivity (83.8%). However, 80% (16/20) of subclinically infected dogs were detected as positive in the assay. Different from LPG, the GIPL-based assay achieved a lower specificity (73.7%) and cross-reactions occurred with T. cruzi and L. braziliensis-infected dogs. Although GIPLs exhibited a similar performance to LPG for subclinically L. infantum-infected dogs, the occurrence of cross-reactivities with other protozoa and a lower sensitivity hinders its use for an immunodiagnostic test. In places where those diseases do not co-exist such as in the Mediterranean region, its use for subclinically dogs could be an alternative.

Highlights

Canine leishmaniasis (CanL) is a chronic zoonosis caused by Leishmania infantum [1]
As part of a wider project on Leishmania glycoconjugates, we evaluated the role of GIPLs for canine leishmaniasis (CanL) immunodiagnosis
For the cross reactivity tests, sera from dogs experimentally infected with T. cruzi in the acute (n = 10) and in the chronic phases (n = 10), and sera from dogs naturally infected with L. braziliensis (n = 11) were used

Summary

Introduction

Canine leishmaniasis (CanL) is a chronic zoonosis caused by Leishmania infantum [1]. Domestic dogs (Canis familiaris) are the main sources of infection for vectors in urban areas representing a key element in the infection’s epidemiology [2]. Leishmaniasis is a spectrum of diseases and in the case of CanL caused by L. infantum, the clinical symptoms are variable, making it difficult to diagnose the infection [3]. Dogs with high parasitic loads typically have more symptomatic and severe disease and are known to be more infectious to the sand fly vectors than resistant dogs [4]. Some susceptible dogs can have high parasitic loads without symptoms at the beginning of an active infection [3]. Early diagnostic of CanL increases the chances for controlling the disease

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