Shifts in surface climate may have changed the dynamic of zoonotic cutaneous leishmaniasis (ZCL) in the pre-Saharan zones of North Africa. Caused by Leishmania major, this form multiplies in the body of rodents serving as reservoirs of the disease. The parasite is then transmitted to human hosts by the bite of a Phlebotomine sand fly (Diptera: Psychodidae) that was previously fed by biting an infected reservoir. We examine the seasonal and interannual dynamics of the incidence of this ZCL as a function of surface climate indicators in two regions covering a large area of the semi-arid Pre-Saharan North Africa. Results suggest that in this area, changes in climate may have initiated a trophic cascade that resulted in an increase in ZCL incidence. We find the correlation between the rainy season precipitation and the same year Normalized Difference Vegetation Index (NDVI) to be strong for both regions while the number of cases of ZCL incidence lags the precipitation and NDVI by 2 years. The zoonotic cutaneous leishmaniasis seasonal dynamic appears to be controlled by minimum temperatures and presents a 2-month lag between the reported infection date and the presumed date when the infection actually occurred. The decadal increase in the number of ZCL occurrence in the region suggests that changes in climate increased minimum temperatures sufficiently and created conditions suitable for endemicity that did not previously exist. We also find that temperatures above a critical range suppress ZCL incidence by limiting the vector’s reproductive activity.
Abstractobjective The incidence of cutaneous leishmaniasis (CL) caused by Leishmania major has increased in Morocco over the last decade, prompting the Ministry of Health to take intersectoral response measures including vector and reservoir control. The aim of this article was to describe the CL outbreak response measures taken in the province of Errachidia, where the reservoir of L. major, a sand rat (Meriones shawi), was targeted using strychnine-poisoned wheat baits from 2010 to 2012.method We analysed routine surveillance data and other information using the data of the CL control programme.results We present data on the evolution and the extension of CL in this province as well as the epidemiological profile of the disease. Between 2004 and 2013, 7099 cases of CL were recorded in Errachidia Province, gradually affecting all districts. Our results demonstrate that more women were affected than men and that all age groups were represented.conclusion Errachidia Province was the epicentre of the recent CL outbreak in Morocco. A notable decline in incidence rates was observed after 2011. The outbreak control measures may have contributed to this decline, as well as climatic trends or progressing herd immunity.
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