The importance of the genus
Thrichomys in the retention of infection and transmission of
Leishmania species is supported by previous studies that describe an ancient interaction between caviomorphs and trypanosomatids and report the natural infection of
Thrichomys spp. Moreover, these rodents are widely dispersed in Brazil and recognized as important hosts of other tripanosomatids. Our main purpose was to evaluate the putative role of
Thrichomys laurentius in the retention of infection and amplification of the transmission cycle of
Leishmania infantum and
L. braziliensis. Male and female
T. laurentius (n = 24) born in captivity were evaluated for the retention of infection with these
Leishmania species and followed up by parasitological, serological, hematological, biochemical, histological, and molecular assays for 3, 6, 9, or 12 months post infection (mpi).
T. laurentius showed its competence as maintenance host for the two inoculated
Leishmania species. Four aspects should be highlighted: (i) re-isolation of parasites 12 mpi; (ii) the low parasitic burden displayed by
T. laurentius tissues; (iii) the early onset and maintenance of humoral response, and (iv) the similar pattern of infection by the two
Leishmania species. Both
Leishmania species demonstrated the ability to invade and maintain itself in viscera and skin of
T. laurentius, and no rodent displayed any lesion, histological changes, or clinical evidence of infection. We also wish to point out the irrelevance of the adjective dermotropic or viscerotropic to qualify
L. braziliensis and
L. infantum, respectively, when these species are hosted by nonhuman hosts. Our data suggest that
T. laurentius may act at least as a maintenance host of both tested
Leishmania species since it maintained long-lasting infections. Moreover, it cannot be discarded that
Leishmania spp. infection in free-ranging
T. laurentius could result in higher parasite burden due the more stressing conditions in the wild. Therefore the tissular parasitism of the skin, infectiveness to the vector, and amplification of the transmission cycle of both
Leishmania species could be expected.
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