A Mother’s Gift: Congenital Transmission of Trypanosoma and Leishmania Species

Kinetoplastids Leishmania infantum and Trypanosoma cruzi, the causative agents of zoonotic visceral leishmaniasis (ZVL) and Chagas’ disease (CD), respectively, can both be transmitted vertically in utero from mother to infant [1]. Congenital infection can be either asymptomatic infection or overt, symptomatic infection [2]. Dogs are a primary domestic reservoir associated with human CD in certain endemic areas and with human ZVL where L. infantum infection predominates. CD, or American Trypanosomiasis, is endemic in 21 countries within the Americas, where classical transmission is via reduviid bugs. Dogs can present with clinical CD. Although rarer, vertical transmission of CD has been reported in dogs. L. infantum (syn. L. chagasi) is one of the Leishmania species causing visceral leishmaniasis (VL). L. donovani, another causative agent of VL and predominantly a human pathogen, has not demonstrated vertical transmission, but this is an understudied area. L. infantum is endemic in the Americas and the Mediterranean region, with primary transmission by sand fly. Although both Lutzomyia shannoni and Lu. anthophora, present in North America, are potential vectors for Leishmania spp. [3], sand fly transmission of L. infantum in North America has not been confirmed. VL is not endemic in North American human populations, but it is endemic in hunting dogs due to vertical transmission of L. infantum [4,5].