Abstract.In rural areas in Morocco, diagnosing cutaneous leishmaniasis (CL) can be challenging. We evaluated the accuracy of a rapid diagnostic test (RDT) based on antigen detection, CL Detect Rapid Test™ (Inbios International Inc., Seattle, WA), in this setting. We consecutively recruited patients with new skin ulcers in nine primary health centers. We took a dental broach sample for the RDT and two other tissue samples by scraping the border and center of the lesion with a scalpel and smearing it on a slide. We duplicated each smear by pressing a clean slide against it and processed the slides by microscopy, polymerase chain reaction (PCR) internal transcribed spacer 1, and kDNA minicircle PCR. In a subgroup with positive PCR, the Leishmania species was identified using PCR-restriction fragment length polymorphism and PCR-sequencing of hsp70 genes. A participant with positive microscopy and/or PCR was considered a confirmed CL case. We computed sensitivity (Se) and specificity (Sp) of the RDT compared with this reference standard (ClinicalTrials.gov registration: NCT02979002). Between December 2016 and July 2017, we included 219 patients, 50% of them were under 18 years old. Rapid diagnostic test Se was 68% [95% confidence interval (CI): 61–74], Sp 94% [95% CI: 91–97], positive predictive value 95% [95% CI: 92–98], and negative predictive value 64% [95% CI: 58–70]. Despite its low Se, this novel RDT is a useful addition to clinical management of CL in Morocco, especially in isolated localities. Rapid diagnostic test–positive lesions can be treated as CL; but when RDT negative, microscopy should be done in a second step. The Se of the RDT can probably be optimized by improving the sampling procedure.
Cutaneous leishmaniasis (CL) caused by Leishmania tropica is emerging in new areas, initially as outbreaks and then establishing endemic foci. There is little evidence of the risk factors and effectiveness of existing control measures, what limits our ability to generalize in different epidemiological settings. The disease is described as anthroponotic; however, zoonotic outbreaks have been reported in some countries. Our aim was to identify risk factors in a recently reported endemic focus in Morocco in order to design more effective control programmes. A case-control study was conducted from September 2014 to October 2015 for epidemiological data collection from families with and without CL cases. Sandflies were captured and L. tropica infection determined. The presence of potential animal reservoirs was evaluated. 71 CL cases (44 diagnosed between 2013 and 2015) and 137 healthy people were surveyed. The average age of the new cases was 33.1 ± 22.3 years, and 69.0% were women. Phlebotomus sergenti was the most abundant species with a density of 4.27 sandflies/trap/night and differences between houses with and without CL cases were detected (p-value = 0.014). Overall, 2.7% female P. sergenti and 3.0% dogs were positive for L. tropica. Human, cat, rabbit and bird blood was detected in blood-fed P. sergenti females. 45% people used preventive measures that were not translated into a reduction in the individual risk of acquiring CL. Exposure to P. sergenti was the only risk factor found, and the reduction in its density could be achieved through the improvement of water wells management, organic fertilizers' disposal and dogs control. The lack of effectiveness of indoor residual spraying and treated nets are attributable to poor compliance and misuse of them. In addition, result optimization of the awareness campaigns on the public is possible by involving patients with CL to explain their own experience.
Anthroponotic cutaneous leishmaniasis (ACL) due to Leishmania tropica is spreading to new areas in Morocco. Exposure to the vector, Phlebotomus sergenti, is the only proven risk factor. Our objective was to compare the densities and genetic characteristics of P. sergenti populations in two nearby localities in Morocco, one in an ACL endemic area (El Borouj) and another in a nonendemic area (Sidi Hajjaj). P. sergenti density was significantly higher in the endemic area than in the nonendemic town (p = 0.032). A different predominant P. sergenti mitochondrial lineage was evidenced in each one of the two localities, and for the first time, the P. sergenti lineage acting as a vector of L. tropica has been identified. Bioclimatic differences were detected between both localities. In conclusion we found differences in both the density and the mitochondrial lineage of P. sergenti populations that may explain the different epidemiological situation. Given that the density of P. sergenti in the locality without ACL cases seems sufficient to allow transmission, the main factor that would justify its nonendemic character could be the absence of P. sergenti Lineage IV, which seems to prefer warmer and drier climates.
Anthroponotic cutaneous leishmaniasis (ACL) due to Leishmania tropica is
spreading to new areas. Exposure to the vector, Phlebotomus sergenti, is
the only proven risk factor. Our objective was to compare the densities
and genetic characteristics of P. sergenti populations in two nearby
localities in Morocco, one within an ACL endemic area (El Borouj) and
another undamaged (Sidi Hajjaj). Statistically significant differences
were detected between P. sergenti densities with a higher density of P.
sergenti in the endemic town (p≤ 0.032). A different main P. sergenti
mitochondrial lineage was evidenced in each one of the 2 localities, and
for the first time, the lineage of P. sergenti specimens that are acting
as a vector of L. tropica has been identified. Bioclimatic differences
were detected between both localities. In conclusion, between an ACL
endemic locality and another ACL free there are differences in both the
density of P. sergenti and the mitochondrial lineage that may explain
the different epidemiological situation. Given that the density of P.
sergenti in the locality without ACL cases seems sufficient to allow
transmission, the main factor that would justify its ACL undamaged
character could be the absence of P. sergenti Lineage IV, which seems to
prefer warmer and drier climates.
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