Sand fly pheromone to reduce transmission of visceral leishmaniasis
A cluster randomised trial is underway in Brazil to test the efficacy of a male sandfly pheromone lure combined with insecticide, to reduce Leishmania infantum incidence in both dogs (the reservoir) and humans (the incidental host). The pheromone released by Lutzomyia longipalpis males mediates blood-seeking female recruitment to lekking aggregations on the host. Under MoH routine insecticide spraying activities, particularly in animal shelters, male sandflies may be killed or prematurely interrupted in their pheromone recruiting process, such that female flies seek alternative unprotected sites/host blood sources. This would defeat the purpose of spraying and ultimately could lead to a potential increase rather than decrease in transmission. In collaboration with Keele University and local partners (Fiocruz-RG, and UNESP) this on-going three-arm trial will examine the benefits of the “lure and kill” approach as compared to insecticide-impregnated collars fitted to dogs, and to a placebo control. The outcomes will include changes in exposure, measured by host anti-sandfly saliva antibody, and changes in infection measured by anti-Leishmania antibody and quantitative PCR of canine skin Leishmania loads. Complimentary entomological data are also being collected.
Personnel: Erin Dilger, Leo Calvo-Bado, Lidija Kravar-Garde, Leopoldo Costa, Talita Branganca
Funders: Wellcome Trust (Strategic Translation Awards)
Collaborators: G. Hamilton (Keele University)
R. Brasil (Fiocruz-RG)
C. Nunes (UNESP)
S. Brandao-Filho (Fiocruz-CPqAM)
Understanding transmission pathways of mucocutaneous leishmaniasis
To understand how to manage variations in L. braziliensis disease incidence in the Atlantic Forest regions of Brazil, requires quantification of the complex transmission pathways between wild and peridomestic vector and host species. In collaboration with local partners (Fiocruz-PE and Fiocruz-RG), contributing on-going PhD studies include infection and infectivity studies of a live-mark-recaptured cohort of 600 naturally infected wild rodents to characterise epidemiologically important wildlife reservoir(s); spill-over reservoir species in peridomestic settings, and long term trends in exposure and infection in sympatric human populations involving leishmanin skin test demographic surveys.
Personnel: Juliana Figuerido da Costa Lima, José Ferreira Marinho Júnior
Funders: Brazilian government (CNPq- Science Without Borders program)
Collaborators: S. Brandao-Fiho Fiocruz-CPqAM, R. Brasil Fiocruz-RG