Phlebotomus sergenti in a cutaneous leishmaniasis focus in Azilal province (High Atlas, Morocco): molecular detection and genotyping of Leishmania tropica, and feeding behavior

PLoS Negl Trop Dis. 2015 Mar 31;9(3):e0003687. doi: 10.1371/journal.pntd.0003687. eCollection 2015 Mar.

Abstract

Background: Phlebotomus (Paraphlebotomus) sergenti is at least one of the confirmed vectors for the transmission of cutaneous leishmaniasis caused by Leishmania tropica and distributed widely in Morocco. This form of leishmaniasis is considered largely as anthroponotic, although dogs were found infected with Leishmania tropica, suggestive of zoonosis in some rural areas.

Methodology and findings: This survey aimed at (i) studying the presence of Leishmania in field caught Phlebotomus sergenti, (ii) investigating genetic diversity within Leishmania tropica and (iii) identifying the host-blood feeding preferences of Phlebotomus sergenti. A total of 4,407 sand flies were collected in three rural areas of Azilal province, using CDC miniature light traps. Samples collected were found to consist of 13 species: Phlebotomus spp. and 3 Sergentomyia spp. The most abundant species was Phlebotomus sergenti, accounting for 45.75 % of the total. 965 female Phlebotomus sergenti were screened for the presence of Leishmania by ITS1-PCR-RFLP, giving a positive rate of 5.7% (55/965), all being identified as Leishmania tropica. Nucleotide heterogeneity of PCR-amplified ITS1-5.8S rRNA gene-ITS2 was noted. Analyses of 31 sequences obtained segregated them into 16 haplotypes, of which 7 contain superimposed peaks at certain nucleotide positions, suggestive of heterozygosity. Phlebotomus sergenti collected were found to feed on a large variety of vertebrate hosts, as determined by Cytochrome b sequencing of the DNA from the blood meals of 64 engorged females.

Conclusion: Our findings supported the notion that Phlebotomus sergenti is the primary vector of Leishmania tropica in this focus, and that the latter is genetically very heterogeneous. Furthermore, our results might be suggestive of a certain level of heterozygosity in Leishmania tropica population. This finding, as well as the feeding of the vectors on different animals are of interest for further investigation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Dogs / parasitology
  • Feeding Behavior / physiology
  • Female
  • Genetic Variation*
  • Genotype
  • Haplotypes / genetics
  • Insect Vectors / parasitology*
  • Leishmania tropica / genetics*
  • Leishmaniasis, Cutaneous / epidemiology*
  • Male
  • Molecular Sequence Data
  • Morocco / epidemiology
  • Phlebotomus / parasitology*
  • Polymerase Chain Reaction
  • Polymorphism, Restriction Fragment Length
  • Sequence Analysis, DNA

Grants and funding

This work was supported by Regional Office for the Eastern Mediterranean-Committee on Science and Technological Cooperation grant; RAB&GH 10-11/09. A part of this work was also supported by the European Virus Archive (European Union Seventh Framework Programme under grant agreement no. 228292)(http://www.european-virus-archive.com/) and the EDENext Seventh Framework Programme - n°261504 EU project. The EDENext FP7- n°261504 EU project and this paper is catalogued by the EDENext Steering Committee as EDENext331 (http://www.edenext.eu). The work of RNC was done under the frame of European Network for Neglected Vectors and Vector-Borne Infections COST Action TD1303. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.