Visceral Leishmaniasis in Emilia-Romagna (Leishmania-2019)

The term leishmaniasis refers to a heterogeneous group of anthropo-zoonoses caused by protozoa obligate intracellular protozoa, parasites of humans and various wild and domestic animals, belonging to the genus Leishmania. Despite being the cause of recurrent epidemic outbreaks with high rates of morbidity and mortality rates in certain geographical areas, the World Health Organisation (WHO) includes them among the Neglected Tropical Diseases. About 350 million people live in areas at risk for leishmaniasis with an estimated global prevalence of 12 million. The annual global incidence is estimated to be between 0.2 and 0.4 million cases for Visceral Leishmaniasis (LV) and between 0.7 and 1.2 million cases for Cutaneous Leishmaniasis Cutaneous. Leishmaniases are endemic infections in tropical, subtropical and temperate zones of all continents except Australia and Antarctica. More than 90% of LV cases are diagnosed in six countries: Bangladesh, Brazil, Ethiopia, India, South Sudan and Sudan, while the majority of LC cases are diagnosed in Afghanistan, Algeria, Brazil, Colombia, Iran, Pakistan, Peru, Saudi Arabia and Syria.

Leishmaniasis is also endemic in the Mediterranean Basin, including Italy, and in this area about 5% of global cases are found there, with a clear prevalence of visceral forms.

The incubation period varies from 4 to 10 months, but cases have been described in which incubation lasted for several years.

The onset is mostly gradual and insidious and the most characteristic clinical manifestations are asthenia fever (often initially framed as FUO), night sweats, anorexia and weight loss, splenomegaly, hepatomegaly and lymphadenomegaly. From a laboratory point of view, characteristic are anaemia, leucopenia and thrombocytopenia, more or less associated with each other, up to full-blown pancytopenia.

Dysprotidemia with hypergammaglobulinemia and hypoalbuminemia is typical. If not adequately treated, visceral leishmaniasis evolves towards a condition of cachexia and profound general decay and may prove fatal. A rare and serious complication of LV is the haemophagocytic syndrome. According to the 2010 WHO Leishmaniasis Control Report, a confirmed case of LV is defined as the association between typical clinical signs and symptoms (fever, splenomegaly, weight loss, etc.) and positivity of a parasitological examination (microscopy, RT-PCR or culture) in the presence or absence of positivity of serological investigations.

The methods available for the diagnosis of LV include:

• Serological tests: detection of Leishmania-specific IgG (or total Ig) in plasma or serum. enzyme immunoassay (EIA), indirect immunofluorescence assay (IFAT), immunochromatographic test (ICT) based on the immunochromatographic test (ICT) based on rK39 antigen, Western blot (WB). Disadvantages: these tests remain positive over time (it is not always possible to distinguish relapses); they may be positive in individuals with asymptomatic infection; they may be falsely negative in immunodepressed individuals (20-60% of cases).
• Molecular biology tests: detection of Leishmania DNA by RT-PCR on peripheral blood bone marrow blood or any other material. Molecular tests are now considered the most sensitive methods sensitive for the diagnosis of LV and the accuracy in identifying Leishmania DNA is high for bone marrow aspirate and peripheral blood samples. RT-PCR should be performed in case the presence of suspicious symptoms and serological test positivity. However, in the presence of strong suspicion clinical suspicion or in immunocompromised patients, RT-PCR should also be performed in case of a negative serology test.

Quantitative RT-PCR on peripheral blood may be useful in patients immunocompromised patients for monitoring parasitukaemia during therapy.

Direct microscopic examination on bone marrow blood smear: sensitivity is variable (25-85%) and lower than the sensitivity of molecular methods.

• Culture examination: culture isolation from bone marrow blood takes a long time (at least 4 weeks). Culture allows the isolation of the strain of Leishmania responsible for the disease and can also be can also be performed from biopsy tissue.

According to reports in the literature, from 2012 to date, there has been an increase in the number of diagnosed cases of autochthonous visceral Leishmania in the Province of Bologna.

In this context, it was decided to carry out a retrospective prospective observational study, which is essential to describe the epidemiology of LV in order to outline the scientific and rational bases necessary for the drafting of guidelines to standardise the diagnostic and therapeutic approach to this disease, in order to reduce the diagnostic delay and improve therapeutic results.

therapeutic outcome. In addition, epidemiological data will make it possible to identify possible new strategies to control the disease, which are essential for reducing its transmission.