Visceral Leishmaniasis: Epidemiology, Diagnosis, and Treatment Regimens in Different Geographical Areas with a Focus on Pediatrics

Abstract

Visceral Leishmaniasis (VL) is a vector-borne disease caused by an intracellular protozoa of the genus Leishmania that can be lethal if not treated. VL is caused by Leishmania donovani in Asia and in Eastern Africa, where the pathogens’ reservoir is represented by humans, and by Leishmania infantum in Latin America and in the Mediterranean area, where VL is a zoonotic disease and dog is the main reservoir. A part of the infected individuals become symptomatic, with irregular fever, splenomegaly, anemia or pancytopenia, and weakness, whereas others are asymptomatic. VL treatment has made progress in the last decades with the use of new drugs such as liposomal amphotericin B, and with new therapeutic regimens including monotherapy or a combination of drugs, aiming at shorter treatment duration and avoiding the development of resistance. However, the same treatment protocol may not be effective all over the world, due to differences in the infecting Leishmania species, so depending on the geographical area. This narrative review presents a comprehensive description of the clinical picture of VL, especially in children, the diagnostic approach, and some insight into the most used pharmacological therapies available worldwide.

Case report: Diagnosis of visceral leishmaniasis using metagenomic next-generation sequencing and bone marrow smear

“…The condition is most prevalent in India, Bangladesh, Sudan, South Sudan, and Ethiopia, where cases are caused primarily by Leishmania donovani, and in Brazil, where Leishmania infantum is prevalent. These six countries account for more than 90% of all VL cases (Ejazi and Ali, 2013;Zijlstra, 2019;Scarpini et al, 2022). In the early 1950s, leishmaniasis was one of the most serious parasitic diseases in China.…”

“…There are three main clinical types of leishmaniasis: visceral, cutaneous, and mucosal (Scarpini et al, 2022). Cutaneous leishmaniasis is relatively rare in China, whereas VL occurs sporadically.…”

“…PCR tests have high sensitivity (>95%) in spleen, bone marrow, lymph node, and peripheral blood samples. However, the specificity is low, and false-positive results may occur (van Griensven and Diro, 2019;Scarpini et al, 2022). In recent years, some studies have found that qPCR analysis of mitochondrial DNA minicircle network (kDNA) based on the characteristics of Leishmania genus has high sensitivity and specificity, and can thus be useful for quantitative detection of pan-Leishmania (Ceccarelli et al, 2020;de Carvalho et al, 2022;Mota et al, 2022).…”

“…The clinical symptoms of VL include fever, pancytopenia, splenomegaly, and emaciation. Patients may be asymptomatic in the initial stage of the disease, and the incubation period typically lasts several weeks to more than one year (van Griensven and Diro, 2019;Scarpini et al, 2022). The case fatality rate is more than 95% in individuals with symptomatic disease, if untreated or if treatment is delayed (Gao et al, 2022).…”

Leishmaniasis: Recent epidemiological studies in the Middle East

“…Worldwide, over 12 million people are infected with Leishmania spp., and an additional 350 million are at risk of infection ( Lockard et al, 2019 ). A high prevalence of leishmaniasis is found primarily among poor populations of the poorest countries impacted by underfunded elimination programs, little to no interest from pharmaceutical industries, and inadequate healthcare infrastructure ( Choi et al, 2021 ; Oliìas-Molero et al, 2021 ; Scarpini et al, 2022 ). These factors contribute to the spread and proliferation of the disease.…”