The estimated distribution of autochthonous leishmaniasis by Leishmania infantum in Europe in 2005-2020

BACKGROUND

This study describes the spatial and temporal distribution between 2005 and 2020 of human and animal leishmaniasis by Leishmania infantum in European countries reporting autochthonous cases, and highlights potential activities to improve disease control.

METHODOLOGY/PRINCIPAL FINDINGS

It was based on a review of the scientific literature and data reported by the World Health Organization (WHO), the World Organization for Animal Health (WOAH) and the Ministries of Health, including hospital discharges in some countries. Autochthonous infections were reported in the scientific literature from 22 countries, including 13 and 21 countries reporting human and animal infections, respectively. In contrast, only 17 countries reported autochthonous human leishmaniasis cases to the WHO and 8 countries animal infections to the WOAH. The number of WOAH reported cases were 4,203, comprising 4,183 canine cases and 20 cases in wildlife. Of 8,367 WHO reported human cases, 69% were visceral leishmaniasis cases-of which 94% were autochthonous-and 31% cutaneous leishmaniasis cases-of which 53% were imported and mostly in France. The resulting cumulative incidence per 100,000 population of visceral leishmaniasis between 2005-2020, was highest in Albania (2.15 cases), followed by Montenegro, Malta, Greece, Spain and North Macedonia (0.53-0.42), Italy (0.16), Portugal (0.09) and lower in other endemic countries (0.07-0.002). However, according to hospital discharges, the estimated human leishmaniasis incidence was 0.70 in Italy and visceral leishmaniasis incidences were 0.67 in Spain and 0.41 in Portugal.

CONCLUSIONS/SIGNIFICANCE

Overall, there was no evidence of widespread increased incidence of autochthonous human leishmaniasis by L. infantum in European countries. Visceral leishmaniasis incidence followed a decreasing trend in Albania, Italy and Portugal, and peaked in Greece in 2013, 2014 and 2017, and in Spain in 2006-2007 and 2011-2013. Animal and human cutaneous leishmaniasis remain highly underreported. In humans, hospital discharge databases provide the most accurate information on visceral leishmaniasis and may be a valuable indirect source of information to identify hotspots of animal leishmaniasis. Integrated leishmaniasis surveillance and reporting following the One Health approach, needs to be enhanced in order to improve disease control.

The role of CD1a expression in the diagnosis of cutaneous leishmaniasis, its relationship with leishmania species and clinicopathological features

Cutaneous leishmaniasis is caused by a flagellated protozoan transmitted by the bite of a female sandfly. The clinical and demographic details of this disease, predominantly affecting immunocompetent individuals, are recognized by the WHO as a Neglected Tropical Disease. We sought to determine the usability of CD1a immunohistochemical staining to detect amastigotes especially in cases where leishmaniasis is suspected but evident amastigotes could not observed. We also evaluated the relationship between CD1a expression and leishmania subtypes. A total of 84 cases diagnosed with leishmaniasis or suspected leishmania on histo-morphological evaluation of skin biopsies were included in the study. Amastigotes were easily detected in hematoxylin eosin in 18 of 84 cases. In 23 cases, amastigotes could not detect in hematoxylin eosin sections. The immunostains for CD1a are demonstrated amastigotes in 60 of 84 cases. However, a small number of amastigotes became visible by positive staining with CD1a in 43.4% of the cases in that amastigotes could not detected in hematoxylin eosin. A statistically significant correlation was found between amastigote amount in hematoxylin eosin and CD1a expression. In addition, a significant correlation was observed between CD1a expression, age and clinical pre-diagnosis of the cases. It was observed that amastigotes were easily detected in hematoxylin eosin in Leishmania Infantum / donovani positive cases in polymerase chain reaction (PCR), and at the same time, it was found that CD1a expression was significantly higher. Using histopathology examination with CD1a staining and/or PCR methods, a diagnosis of leishmaniasis can be established and early treatment initiated. This contributes to reduce transmission and prevalence.

In vivo reflectance confocal microscopic imaging of Leishmania amastigotes (Leishman bodies): A case report

Cutaneous leishmaniasis (CL) is an intracellular parasitic infectious skin disease with a chronic self-limited course. In vivo reflectance confocal microscopy (RCM) findings in CL have been described in only two cases of CL. We report another case with RCM findings; however to our knowledge, this is the first demonstration of Leishmania amastigotes in RCM imaging. A centrally eroded reddish nodular lesion with a diameter of 12 mm was observed on the leg of a 36-years-old male with a 1-month history. On dermoscopy, a central yellowish crust, and irregularly distributed whitish opaque structures ranging in size and shape (round to polygonal) were observed. There were also irregular vessels mostly at the center and dotted/glomerular vessels at the periphery. On RCM, mild epidermal disarray with some scattered bright cells at the basal layer was observed. At the dermis, dense infiltration of polymorphic/roundish cells with heterogeneous reflectivity was seen. These large, mildly reflecting cells with fine granular structures in their cytoplasm were compatible with macrophages. Histopathology was concordant with CL. The Leishmania amastigotes seen as cytoplasmic granularity on RCM were the clue feature for the initial diagnosis.

The Role of Histopathology and Immunohistochemistry in the Diagnosis of Cutaneous Leishmaniasis Without "Discernible" Leishman-Donovan Bodies

BACKGROUND

Histopathology plays an important role in the diagnosis of cutaneous leishmaniasis (CL) but Leishman-Donovan (LD) bodies may not always be discernible. Recently, anti-CD1a antibody (Ab), clone MTB1, was found to decorate LD bodies immunohistochemically.

OBJECTIVE

Can histopathology without discernible LD bodies be used to diagnose CL, and can immunohistochemistry using anti-CD1a Ab, clone MTB1, detect LD bodies in these cases.

METHODS

Suspected CL lesions were studied histopathologically and immunohistochemically, and the patients' clinical files were reviewed.

RESULTS

Of the 196 patients with suspected CL, direct smear demonstrated LD bodies in 50 (25.5%). Of the remaining 146 patients, 118 underwent biopsy. In 56 (47.5%) patients, the hematoxylin-eosin-stained sections revealed LD bodies. In 47 (39.8%) patients, LD bodies were not discerned but the histopathology demonstrated histiocytic infiltrates with varying numbers of plasma cells along with other inflammatory cells, and negative Ziehl-Neelsen and periodic acid-Schiff stains. This pattern was termed "histopathology consistent with leishmaniasis." The history, clinical findings, and response to anti-leishmania therapy supported the diagnosis of CL in all of them, and immunostains for CD1a, clone MTB1, detected LD bodies in 11 (23.4%) of these 47 patients.

CONCLUSIONS

"Histopathology consistent with CL" along with appropriate clinical findings supports the diagnosis of CL in an endemic area, and immunostains with CD1a Ab, clone MTB1, may help in the minority of the cases.