ABOUT THE PROJECT

UPDATES ON PROJECT ACTIVITIES

Publications

RESEARCH GROUPS

Structure and management

Endemic Foci of Kala Azar

GALLERY

Sand fly vectors and transmission dynamics of visceral leishmaniasis

The main vector of visceral leishmaniasis (VL) in Sudan and Northern Ethiopia is Phlebotomus orientalis,  a sand fly frequently found in forests of Acacia and Balanites trees where it transmits VL to farmers and hunters during the dry season. However, P. orientalis has also been documented inside villages and even indoors transmitting leishmaniasis to the residents. Itis primarily a lowland species, but in Ethiopia it is also found in altitudes of up to 2,000 m. It has a wide geographical distribution ranging across the Sahel from Sudan and Ethiopia into Djibouti and south Kenya.
For monitoring Kala-Azar transmission in humans, the population density of sand flies will be estimated during different seasons, levels of human exposure to biting sand flies will be estimated by monitoring the rates of sero-conversion to anti-sand fly saliva antibodies. The reservoir potential of different populations such as VL as well as post-kala azar dermal leishmaniasis (PKDL) patients will be determined. Sand fly behavior and ecology will be studied by trapping in different locations / using several methods including light traps, animal and human landing collections and emergence traps for identifying larval breeding habitats. The habitats and distances from which adult females arrive at villages will be estimated using dyed sugar baits to mark flies at different sites. Collections will be performed in and around villages, at different times during the night and at different seasons of the year. Host preferences of vector sand flies as well as Leishmania infection rates will be determined using PCR.
Undoubtedly the widest gap in our knowledge of phlebotomine sand fly biology remains their larval ecology. P. orientalis, the main vector of VL were reported to emerge from cracks in vertisols. Vertisols swell when wet and shrink when dry, consequently promoting cracking in the dry season and flooding during the rainy season. To characterize breeding habitats, sites where many flies emerge from cracks will be compared with sites with relatively few sand flies. The vegetation and/or farming activities will be documented , soil samples will be obtained from different depths, chemically and physically analyzed. Water content and temperature in the soil will be measured continuously comparing productive sand fly breeding habitats and others with very few sand flies. Results should should provide positive and/or negative indicators for sand fly breeding sites.
A thorough understanding of the ecology and behavior of the vector(s) constitutes a crucial aim of the proposed project: including: vector(s) incrimination, where are sand flies breeding? What animals and plants are they feeding upon? Where and when do they transmit L. donovani to humans? A combination of strategies carefully selected following comprehensive ecological/epidemiological studies, will be necessary to combat VL in Ethiopian foci.

Project personnel

1. Alon Warburg, PhD (Principal Investigator) team leader:  alonw@ekmd.huji.ac.il
2. Ibrahim Abassi, PhD (Research associate):  ibrahim@md.huji.ac.il
3. Roy Faiman, MSc (PhD student):  roy.faiman@mail.huji.ac.il
4. Adi Moncaz, MSc  (PhD student):  moncaz@walla.com
5. Oscar David Kirstein, MSc (PhD candidate):  od.kirstein@mail.huji.ac.il
6. Samar Aramin (MSc student):  samar.aramin@gmail.com
   

Alon Warburg’s Vector Biology Laboratory is at the Kuvin Center for the Study of Infectious and Tropical Diseases within The Institute for Medical Research  Israel-Canada at the Hebrew University Faculty of Medicine in Ein Kerem, Jerusalem, Israel. Alon has been studying sand fly vectors of leishmaniasis for many years in several countries. He has also conducted laboratory studies on the development of Leishmania in sand flies as well as Plasmodium (malaria) parasites in mosquitoes.

Selected Publications

1. Wasserberg G., Abramsky Z., Kotler  B.P., Ostfeld R. S., Yarom I .,Warburg A. 2003. Anthropogenic disturbances enhance occurrence of cutaneous leishmaniasis in Israel deserts: patterns and mechanisms. Ecol  Applications 13: 868-881.
2.  Jacobson R.L., Eisenberger C. L.,  Svobodova M., Baneth G., Sztern J.  Carvalho J., Naseredeen  A., El Fari M.  Shalom, U.  Volf P. Votypka J. ,  Dedet J.  Pratlong F. , Sch?nian G. , Schnur L. F. ,  Jaffe C. L. and Warburg A.  2003. Outbreak of cutaneous leishmaniasis in Northern Israel. J Inf Dis  7: 1065-1073.
3. Wasserberg G , Yarom, and Warburg A.  2003. Seasonal Abundance Patterns of Phlebotomus papatasi (Diptera: Psychodidae) in Two Climatically Distinct Foci of Cutaneous Leishmaniasis in Israeli Deserts. Med Vet Entomol, 17: 452-456.
4.  Schnur L.F., Nasereddin A., Eisenberger C., Jaffe C.L., El Fari, Azmi K.,  Anders G., Killick-Kendrick R., Dedet J-P., Pratlong G., Kanaan M., Grossman T.,  Jacobson R.L., Schonian G., and Warburg A. 2004. Multifarious characterization of Leishmania tropica from a Judean desert focus, exposing intraspecific diversity and incriminating Phlebotomus sergenti as its vector. Am J Trop Med Hyg 70: 364-372.
5. Jaffe C.L. , Baneth G. , Abdeen Z. , Schlein, Y . and Warburg ,A 2004. Leishmaniasis in Israel and the Palestinian Authority. Trends Parasitol, 20: 328-332
6. Kravchenko, V., Wasserberg, G. & Warburg, A. 2004. Bionomics of phlebotomine sandflies in the Galilee focus of cutaneous leishmaniasis in northern Israel. Med Vet Entomol. 18:418-428.
7. Svobodov?, M . Vot?pka, J . Peckov?, J . Dvo??k, V . Nasereddin, A. , Baneth, G. , Sztern, J. Kravchenko, V . Orr. A.  Meir, D . Schnur, L.F . Volf, P. and Warburg, A. (2006). Distinct transmission cycles of Leishmania tropica in 2 adjacent foci, northern israel. Emerg Infect Dis, 12: 1860-1868.
8. Warburg, A. Shtern, S.  Cohen ,N.  and Dahan, N.  (2007). Laminin and a Plasmodium ookinete surface protein inhibit melanotic encapsulation of Sephadex beads in the hemocoel of mosquitoes. Microbes Infect,  9: 192-199.
9. Warburg, A, Gelman S . & Deutsch J .  (2008). Xanthine in urine stimulates growth of Leishmania promastigotes in vitro. J Med Microbiol, 57: 136-138.
10. Warburg, A. (2008). The structure of the female sand fly (Phlebotomus papatasi) alimentary canal. Trans R Soc Trop Med Hyg, 102: 161-166.
11. Sirak-Weizman, M., Cunio R., Faiman R. & Warburg A. (2008). Control of phlebotomine sand flies in confined spaces using diffusible repellents and insecticides. Med Vet Entomol, 22:405-412
12. Abbasi, I. Cunio, R. & Warburg, A (2009). Identification of blood meals imbibed by phlebotomine sand flies using cytochrome b PCR and reverse line blotting. Vec Borne Zoonot Dis 9: 79-86.
13. Faiman, R , Cu?o, R   and  Warburg A   (2009). Comparative efficacy of three suction traps for collecting phlebotomine sand flies (Diptera:Psychodidae) in open habitats. J Vec Ecol 34:114-118.
14. Faiman, R , Cu?o, R   and  Warburg A  (2009). Control of Phlebotomine Sand Flies with Vertical Fine-Mesh Nets. J Med Entomol ,46: 820-831.

Alon, dissecting voles to determine infection rates with Leishmania major in Sde Eliyahu

Oscar, counting marked sand flies trapped on sticky surface under the window of an experimental house in Kfar Adumim

Roy, examining emergence traps for presence of sand flies (Sde Boker)

The flight barrier against sand flies transmitting cutaneous leishmaniasis in Sde Eliyahu

Ibrahim Abassi (center right) with Asrat Hailu (left), Teshome Gebre-Michael (center left) and Petr Volf (right) during a tour of Jerusalem (Nov 2009)

Volcani Center, Israel