Recombinant Antigens from Phlebotomus perniciosus Saliva as Markers of Canine Exposure to Visceral Leishmaniases Vector

Jan Drahota,Ines Martin-Martin,Petra Sumova,Maribel Jimenez,Ricardo Molina,Petr Volf,Iva Rohousova,Shaden Kamhawi

doi:10.1371/journal.pntd.0002597

Abstract

Background Phlebotomus perniciosus is the main vector in the western Mediterranean area of the protozoan parasite Leishmania infantum, the causative agent of canine and human visceral leishmaniases. Infected dogs serve as a reservoir of the disease, and therefore measuring the exposure of dogs to sand fly bites is important for estimating the risk of L. infantum transmission. In bitten hosts, sand fly saliva elicits a specific antibody response that reflects the intensity of sand fly exposure. As screening of specific anti-saliva antibodies is limited by the availability of salivary gland homogenates, utilization of recombinant salivary proteins is a promising alternative. In this manuscript we show for the first time the use of recombinant salivary proteins as a functional tool for detecting P. perniciosus bites in dogs.Methodology/Principal FindingsThe reactivity of six bacterially-expressed recombinant salivary proteins of P. perniciosus, yellow-related protein rSP03B, apyrases rSP01B and rSP01, antigen 5-related rSP07, ParSP25-like protein rSP08 and D7-related protein rSP04, were tested with sera of mice and dogs experimentally bitten by this sand fly using immunoblots and ELISA. In the immunoblots, both mice and canine sera gave positive reactions with yellow-related protein, both apyrases and ParSP25-like protein. A similar reaction for recombinant salivary proteins was observed by ELISA, with the reactivity of yellow-related protein and apyrases significantly correlated with the antibody response of mice and dogs against the whole salivary gland homogenate.Conclusions/SignificanceThree recombinant salivary antigens of P. perniciosus, yellow-related protein rSP03B and the apyrases rSP01B and rSP01, were identified as the best candidates for evaluating the exposure of mice and dogs to P. perniciosus bites. Utilization of these proteins, or their combination, would be beneficial for screening canine sera in endemic areas of visceral leishmaniases for vector exposure and for estimating the risk of L. infantum transmission in dogs.

Highlights

Canine leishmaniasis (CanL) is a systemic disease with variable clinical symptoms
CanL is not just a veterinary problem; infected dogs serve as a reservoir host of human visceral leishmaniasis and there is a correlation between the prevalence of leishmaniasis in the canine population and the human disease in many countries [1]
The protozoan parasite Leishmania infantum is a causative agent of zoonotic visceral leishmaniasis, an important and potentially fatal human disease

Summary

Introduction

Canine leishmaniasis (CanL) is a systemic disease with variable clinical symptoms. Its causative agent, the protozoan parasite Leishmania infantum, is transmitted by phlebotomine sand flies (Diptera: Phlebotominae). CanL is not just a veterinary problem; infected dogs serve as a reservoir host of human visceral leishmaniasis and there is a correlation between the prevalence of leishmaniasis in the canine population and the human disease in many countries [1]. Phlebotomus perniciosus is the main vector in the western Mediterranean area of the protozoan parasite Leishmania infantum, the causative agent of canine and human visceral leishmaniases. As screening of specific anti-saliva antibodies is limited by the availability of salivary gland homogenates, utilization of recombinant salivary proteins is a promising alternative. In this manuscript we show for the first time the use of recombinant salivary proteins as a functional tool for detecting P. perniciosus bites in dogs

Methods

Results

Discussion

Conclusion