Recurrent Visceral Leishmaniasis in HIV Co-Infection

Prospective and retrospective observational cohort study

Main objective

\- To identify the key host and pathogen factors that contribute to active chronicity (=recurrent or chronic parasite presence in blood, tissue and/or skin in combination with clinical symptoms) in VL/HIV patients in northern Ethiopia

Specific objectives

* To describe the VL/HIV patients by level of chronicity using routine clinical and laboratory data * To monitor parasite presence by molecular diagnostic in peripheral blood and - if available - tissue aspirates before, during, after treatment as well as during follow-up by level of disease chronicity * To broadly characterize the underlying HIV co-infection and potential of ART resistance by level of disease chronicity * To genotype the Leishmania parasites by level of disease chronicity to assess re-infection, recrudescence, drug resistance, and quiescence/virulence * To identify other concomitant (latent) co-infections (TB, malaria, intestinal helminths, viral infections) and its impact on disease chronicity * To study the level of exhaustion and immune checkpoint inhibition pathways, as potential therapy targets, by disease chronicity * To assess the quality of life by a standardised questionnaire at admission and during follow-up

Exploratory objective:

* To study the persistence and quantity of parasites within the skin * To study the stool microbiome of VL-HIV patients * To assess the potential impact of secondary prophylaxis on relapse frequency, relapse intervals, relapse intensity, and exhaustion marker (compared with historical cohort/patients without secondary prophylaxis)