Advances toward Diagnostic Tools for Managing Zoonotic Visceral Leishmaniasis

Abstract

Visceral leishmaniasis (VL) is a life-threatening outcome of Leishmania infantum or Leishmania donovani infection. Dogs are the primary domestic reservoir of L. infantum parasites, and ownership of infected dogs increases the risk of human VL. Controlling infection within dog populations is regarded as critical to VL management in endemic countries, both preventing progression of canine disease and limiting parasite transmission to humans and dogs. Here we discuss various strategies that are used to diagnose canine visceral leishmaniasis (CVL) and the possibilities of adapting these for use within population screening and control programs. In addition, given the variable transmissibility of L. infantum to the sand fly vector, we outline some possibilities for the preferential identification of 'super-spreader' dogs among the overall infected population.

Keywords: asymptomatic; canine; diagnosis; leishmaniasis; serology.

Figure 1.. Transmission of VL-causing Leishmania among dogs and humans.

A Venn diagram depicting the progression of Leishmania-infected dogs and/or humans to an infectious state culminating in presentation of VL. While L. infantum can circulate in, and be transferred between, dog and human populations via sand fly vectors, L. donovani is limited to human populations.

Figure 2.. Diagnostic and detection strategies.

The progression of diagnostic strategies from direct detection methods to indirect, antibody-detection techniques is depicted. As antibodydetection methods are refined, the possibility of using “simpler-to-collect” (i.e., less invasive) samples that are more permissive for large-scale surveillance programs is presenting themselves.