Preclinical diagnosis of American visceral leishmaniasis during early onset of human Leishmania (L.) infantum chagasi-infection

American visceral leishmaniasis (AVL) is an infectious disease, often with long-duration evolution, caused by Leishmania (L.) infantum chagasi. However, although the disease is considered the major clinical manifestation of the link between L. (L.) i. chagasi and the human immune response, we have recently identified five clinical–immunological profiles of infection in the Brazilian Amazon: three asymptomatic (Asymptomatic Infection — AI, Sub-clinical Resistant Infection — SRI, and Indeterminate Initial Infection — III), and two symptomatic ones [Symptomatic Infection — SI ( = AVL) and Sub-clinical Oligosymptomatic Infection — SOI]. We confirm here the preclinical diagnosis of AVL through the IgM-antibody response in a case of an early infection (profile III) that evolved to the full disease after 6 weeks.