Emerging and Re-Emerging Leishmaniases in the Mediterranean Area: What Can Be Learned from a Retrospective Review Analysis of the Situation in Morocco during 1990 to 2010?

Abstract

In Morocco, cutaneous and visceral leishmaniases represent a public health concern. In this opinion paper, we propose to highlight chosen elements that have governed the drastic increase in the incidence of leishmaniases recorded in Morocco during the period between 1990 to 2010 in order to guide the prediction of the expansion of diseases and epidemic events. We highlight that the dispersion of the zoonotic cutaneous leishmaniasis (ZCL) form, caused by the Leishmania major parasite, appears to be closely related to that of its arthropod vector density, which is sensitive to changes in climate. The dissemination of anthroponotic cutaneous leishmaniasis (ACL) was related to an increase in human travel and local tourism during the studied decades. These are linked to economic expansion and infrastructure development. Interestingly, the main ACL foci are spatially aligned with the highways, and their occurrence was synchronized with the building of transportation infrastructure. During the above-mentioned decades, the zoonotic visceral leishmaniasis (ZVL) caused by Leishmania infantum has expanded from its historical northern territories, dispersing outwards in all directions. This spread follows the emergence of hamlets and villages connecting with major cities.

Trends in the Epidemiology of Leishmaniasis in the City of Barcelona (1996–2019)

“…Among population from foreign country of birth, there is a persistent increase of incidence since 2003, consistent with a rise in foreign population migrating to Barcelona (3.8% of the total population in 1996 to 25.7% in 2019) ( 31 ), but also to international traveling to endemic areas, due to tourism, visiting relatives and work ( 22 , 36 ). The difference between autochtonous and imported cases is difficult to establish due to the long incubation period of leishmaniasis (2 weeks to several years), and inconsistencies in the reporting of identified Leishmania species.…”

“…In Morocco, the increase in minimum temperatures has increased the survival of the sandfly larvae through the winters, extending their activity season. This combined with the increase in human circulation and tourism is thought to be one of the main causes for dissemination of cutaneous leishmaniasis ( 22 ). Spain has also experienced an increase in cases, though this phenomenon has been attributed to multiple factors, including improvements in notification, the seasonality of sandflies ( 16 ) and a growing urbanization that favors the contact between reservoirs and humans ( 23 ).…”

Impact of Climatic Factors on the Seasonal Fluctuation of Leishmaniasis Vectors in Central Morocco (Meknes Prefecture)

“…In the prefecture of Meknes, two types of leishmaniasis coexist: visceral and cutaneous leishmaniasis that might have propagated from Taounate to the foci of Meknes and Sidi-Kacem via Fez, with stray dogs carrying the infection across hamlets and villages in their quest for food and shelter [ 17 ].…”

Investigation of natural infection of Phlebotomine (Diptera: Psychodidae) by Leishmania in Tunisian endemic regions

“…Whereas CCL caused by L. tropica is no longer restricted to South-eastern Tunisia ( Haouas et al, 2012 ). Such extension over historical foci has also been recorded in Morocco ( Kholoud et al, 2018 ) ( Kholoud et al, 2020 ) ( Guernaoui et al, 2020 ). -Such expansion in territories has favored the emergence of CL mixed foci of L. tropica and L. major.…”