Examining the reservoir potential of animal species for $$\varvec{\textit{Leishmania infantum}}$$ Leishmania infantum infection

Abstract

Leishamaniasis is a parasitic disease transmitted by sandfly Phlebotomus spp. and is seen in tropical and subtropical countries in which an estimated 12 million persons are infected. Among various types of leishmaniasis, zoonotic visceral leishmaniasis (ZVL) caused by Leishmania infantum is an important amphixenosis shared by human and other animals. Although identifying the natural reservoir host would help better understand the transmission dynamics of Leishmania spp., little effort has been made to quantitatively clarify the dynamics involving the reservoir host of ZVL. The present study investigated the reservoir potential of four wild animals in maintaining ZVL, using prevalence data from Latin American countries in Amazons and examining the role of crab-eating fox, spiny rat, common opossum and black rat in maintaining the transmission. Reflecting frequent reinfections, a susceptible-infectedsusceptible model was employed, enabling us to estimate model parameters from endemic prevalence data. The next generation matrix of the multi-host system was computed, permitting us to theoretically examine the reservoir potential of each animal species. Our estimates indicated that there is no unique reservoir host consisting of single animal species. Crab eating fox was considered to play an important role in maintaining L. infantum transmission, but this was the case only in combination with other hosts. The present study indicates that animal species other than canine play important roles in maintaining transmission of Leishmania infantum, which is different from conventional wisdom that centered on the importance of canine only. Greater sample size with additional entomological and genetic insights into inter-specific contact would be required to implement more explicit assessments.