Do humans comprise a significant source of infection for the sand fly vectors of visceral leishmaniasis in north Brazil?

• Grant number: 11/51404-9
• Support Opportunities: Regular Research Grants
• Start date: December 01, 2011
• End date: July 31, 2014
• Field of knowledge: Health Sciences - Medicine - Pathological Anatomy and Clinical Pathology
• Agreement: Hebrew University of Jerusalem - HUJ
• Principal Investigator: Marcia Dalastra Laurenti
• Grantee: Marcia Dalastra Laurenti
• Principal researcher abroad: Alon Warburg
• Institution abroad: Hebrew University of Jerusalem, Israel
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

In Brazil transmission of visceral leishmaniasis (VL) is mostly zoonotic with dogs serving as reservoir hosts. However culling of infected dogs has failed to reduce transmission suggesting the possible contribution of humans as parasite reservoirs for infecting sand flies. Competent reservoir hosts must be abundant and long lived. The infection should be long enough and non-pathogenic to permit survival of the infected/infective hosts. Sufficient parasite loads should be present in the skin and/or blood to promote high infection rates in biting vectors. The current project will evaluate whether humans living in a VL endemic area, fulfill these criteria. An epidemiological survey in a peri-urban focus Bujarú near Belem will characterize different immunological/clinical profiles (skin test, immuno-fluorescent assay) with respect to VL and verify the physical presence of parasites in the blood by real-time PCR, parasite culture and artificial xenodiagnosis. The data will be used to assess which sub-population contributes most to infection of sand flies. Data will be compared with similar data derived from a project on going in Ethiopia where the disease is primarily anthroponotic. Results will shed light on the possible role of humans as reservoir hosts of L. infantum in Brazil. (AU)