Transmission of Leishmania infantum in the Canine Leishmaniasis Focus of Mont-Rolland, Senegal: Ecological, Parasitological and Molecular Evidence for a Possible Role of Sergentomyia Sand Flies.
Leishmania (L.) infantum is the causative agent in an endemic focus of canine leishmaniasis in the Mont-Rolland district (Thiès, Senegal). In this area, the transmission cycle is well established and more than 30% of dogs and 20% of humans are seropositive for L. infantum. However, the sand fly species involved in L. infantum transmission cycle are still unknown. Between 2007 and 2010, 3654 sand flies were collected from different environments (indoor, peridomestic, farming and sylvatic areas) to identify the main L. infantum vector(s). Nine sand fly species were identified. The Phlebotomus genus (n = 54 specimens; Phlebotomus (Ph) duboscqi and Phlebotomus (Ph). rodhaini) was markedly under-represented in comparison to the Sergentomyia genus (n = 3600 specimens; Sergentomyia (Se) adleri, Se. clydei, Se. antennata, Se. buxtoni, Se. dubia, Se. schwetzi and Se. magna). Se. dubia and Se. schwetzi were the dominant species indoor and in peridomestic environments, near humans and dogs. Blood-meal analysis indicated their anthropophilic behavior. Some Se. schwetzi specimens fed also on dogs. The dissection of females in the field allowed isolating L. infantum from sand flies of the Sergentomyia genus (0.4% of Se. dubia and 0.79% of Se. schwetzi females). It is worth noting that one Se. dubia female not engorged and not gravid revealed highly motile metacyclic of L. infantum in the anterior part of the midgut. PCR-based diagnosis and sequencing targeting Leishmania kinetoplast DNA (kDNA) highlighted a high rate of L. infantum-positive females (5.38% of Se. dubia, 4.19% of Se. schwetzi and 3.64% of Se. magna). More than 2% of these positive females were unfed, suggesting the parasite survival after blood-meal digestion or egg laying. L. infantum prevalence in Se. schwetzi was associated with its seroprevalence in dogs and humans and L. infantum prevalence in Se. dubia was associated with its seroprevalence in humans. These evidences altogether strongly suggest that species of the Sergentomyia genus are probably the vectors of canine leishmaniasis in the Mont-Rolland area and challenge one more time the dogma that in the Old World, leishmaniasis is exclusively transmitted by species of the Phlebotomus genus.
Laboratory of Terrestrial Invertebratede Zoology, IFAN (Institut Fondamental d'Afrique Noire), Université Cheikh Anta Diop, Dakar, Senegal.|MIVEGEC (UMR IRD 224-CNRS 5290- Université Montpellier), Montpellier, France.
Massila Wagué
MW
Senghor
Laboratory of Terrestrial Invertebratede Zoology, IFAN (Institut Fondamental d'Afrique Noire), Université Cheikh Anta Diop, Dakar, Senegal.
Abdoul Aziz
AA
Niang
Laboratory of Parasitology Mycology, Faculty of Medicine, Pharmacy and Odonto-Stomatology, University Cheikh Anta Diop, Dakar, Senegal.
Jérome
J
Depaquit
Laboratory of Parasitology Mycology, Faculty of Medicine, Pharmacy and Odonto-Stomatology, University Cheikh Anta Diop, Dakar, Senegal.
Hubert
H
Ferté
Laboratory of Terrestrial Invertebratede Zoology, IFAN (Institut Fondamental d'Afrique Noire), Université Cheikh Anta Diop, Dakar, Senegal.
Malick Ndao
MN
Faye
MIVEGEC (UMR IRD 224-CNRS 5290- Université Montpellier), Montpellier, France.
Eric
E
Elguero
Université de Reims Champagne-Ardenne, ANSES, EA4688 - USC «transmission vectorielle et épidémiosurveillance de maladies parasitaires (VECPAR)», SFR Cap Santé, Faculté de Pharmacie, Reims, France.
Oumar
O
Gaye
MIVEGEC (UMR IRD 224-CNRS 5290- Université Montpellier), Montpellier, France.|Department of Biology (Zoology Section) Faculty of Science, Hacettepe University, Beytepe - Ankara, Turkey.
Bulent
B
Alten
Department of Biology (Zoology Section) Faculty of Science, Hacettepe University, Beytepe - Ankara, Turkey.
Utku
U
Perktas
MIVEGEC (UMR IRD 224-CNRS 5290- Université Montpellier), Montpellier, France.
Cécile
C
Cassan
Université de Reims Champagne-Ardenne, ANSES, EA4688 - USC «transmission vectorielle et épidémiosurveillance de maladies parasitaires (VECPAR)», SFR Cap Santé, Faculté de Pharmacie, Reims, France.
Babacar
B
Faye
MIVEGEC (UMR IRD 224-CNRS 5290- Université Montpellier), Montpellier, France.
Anne-Laure
AL
Bañuls
D000818:Animals; D004283:Dog Diseases / Q000097:blood / Q000453:epidemiology / Q000469:parasitology / Q000635:transmission*; D004285:Dogs; D004463:Ecology; D005260:Female; D006801:Humans; D007303:Insect Vectors / Q000469:parasitology*; D018314:Leishmania infantum / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D007896:Leishmaniasis / Q000453:epidemiology / Q000469:parasitology / Q000635:transmission* / Q000662:veterinary*; D008297:Male; D011576:Psychodidae / Q000469:parasitology*; D012675:Senegal / Q000453:epidemiology; D016036:Seroepidemiologic Studies