Visceral leishmaniasis in a patient with AIDS: early pathological diagnosis using conventional histology, PCR and electron microscopy is the key for adequate treatment

Leishmaniases diagnosis: an update on the use of immunological and molecular tools

Leishmaniases are caused by obligate intracellular protozoan parasites of the genus Leishmania. They cause a spectrum of diseases, most notably visceral (VL), cutaneous (CL), and mucosal (ML) leishmaniasis, which affect millions of people around the world, each year. Despite scientific advances, leishmaniases cases are expanding, constituting an important public health problem. Immunological and molecular diagnostic tools have been increasingly applied for the early detection of these parasitic infections, since the existence of limitations in clinical and parasitological examinations may provide false results, thus interfering in epidemiological research and diseases control. Although there is a great diversity of available immunological assays, important common deficiencies persist, which explains the current exploration of the molecular biology in research fields, especially the Polymerase Chain Reaction (PCR) and its variants, such as real-time quantitative PCR. However, in the last years, significant results have also been reached inside of immunological context (especially by Flow Cytometry), for humans and dogs, demonstrated by research works of the New and Old worlds. In spite of their potential to clarify and minimize the present global situation of the diseases, the implementation of molecular or immunological innovative reference assays for VL and CL at health services is still a challenge due to several reasons, including lack of standardization among laboratories and structural concerns. In this article we bring classical and current information about technological advances for the immunological and molecular leishmaniases diagnosis, their features, and applications.

Current clinical, laboratory, and treatment outcome characteristics of visceral leishmaniasis: results from a seven-year retrospective study in Greece

OBJECTIVES

Visceral leishmaniasis (VL) is re-emerging in endemic areas. The epidemiological, clinical, laboratory, and treatment outcome characteristics in a large cohort of VL patients is described herein.

METHODS

The cases of 67 VL patients (57% male, mean age 56 years) treated in two Greek hospitals over the last 7 years were identified and evaluated retrospectively.

RESULTS

Forty-six percent of patients reported contact with animals. Seventeen patients (25%) were immunocompromised, and 22% were co-infected with another pathogen. Sixty-four percent of patients had fever, 57% had weakness, 37% had sweats, 21% had weight loss, and 13% had a dry cough, while 6% developed haemophagocytic syndrome. The median duration of symptoms was 28 days. Fifty-eight percent of patients had splenomegaly, 49% had hepatomegaly, and 36% had lymphadenopathy. The diagnosis was established by positive PCR in peripheral blood (73%) and/or bone marrow specimens (34%). Sixty-one patients (91%) received liposomal amphotericin (L-AMB). Six patients (10%) did not respond or relapsed but were eventually cured after a second cycle of L-AMB. During a 6-month follow-up, the overall mortality was 9%, although none of these deaths was attributed to VL.

CONCLUSIONS

VL is still a common disease in endemic areas, affecting immunocompetent and immunocompromised patients. Its diagnosis is challenging, and molecular techniques are valuable and helpful tools to achieve this. Treatment with L-AMB is safe and very effective.

Immune regulation during chronic visceral leishmaniasis

Visceral leishmaniasis is a chronic parasitic disease associated with severe immune dysfunction. Treatment options are limited to relatively toxic drugs, and there is no vaccine for humans available. Hence, there is an urgent need to better understand immune responses following infection with Leishmania species by studying animal models of disease and clinical samples from patients. Here, we review recent discoveries in these areas and highlight shortcomings in our knowledge that need to be addressed if better treatment options are to be developed and effective vaccines designed.