ABOUT THE PROJECT

UPDATES ON PROJECT ACTIVITIES

Publications

RESEARCH GROUPS

Structure and management

Endemic Foci of Kala Azar

GALLERY

Vector Biology Charles University, Czech Republic

The team will is involved in several key aspects of the project. During the initial operational phase most of our efforts are devoted to field studies on sand flies in endemic foci in Ethiopia.  We are  participating in ecological studies of transmission cycles, sand fly colonization, sand fly taxonomy, artificial feeding for infection, development of ELISA assays for determining sero-conversion to sand fly saliva as a means for assessing the burden of exposure to biting sand flies and, thereby, the potential for infection with L. donovani. During subsequent years of the project, we will be actively involved in design, implementation and monitoring of transmission dynamics and ecology of sand fly populations densities and species composition as well as human sero-conversion to sand fly saliva.

Studies on sand fly ecology will comprise several tasks. Sand flies in the VL foci will be trapped by several methods in order to study their occurrence, seasonality, feeding and breeding site preferences and Leishmania infection rate.  Caught females will be checked for presence of Leishmania promastigotes by dissection and later by PCR (k-DNA, ITS-1) methods. Isolated Leishmania strains will be cultivated and inoculated into  appropriate mammalian hosts. All sand fly collection sites together with patient cases will be registered in GIS databases and compared with selected environmental features; such analysis and compilation of the data will bring knowledge about spatial distribution and spacing of vectors and will facilitate identification of risk factors.

The existence of sibling species, population differences and intraspecific variability of P. orientalis and other putative vectors will be tested using several molecular methods (ITS and cyt b haplotype analysis, RAPD analysis and panels of microsatellite markers) and morphological method (geometric morphometric analysis). Biological relevance of analyzed molecular differences will be evaluated by a cross-mating study, enabled by establishment of laboratory colonies.

Colonies of P. orientalis from several leishmaniasis foci over Ethiopia (and eventually those of  other putative vectors,  P. martini and P. celiae) will be established in order to complete the whole transmission cycle under laboratory conditions. Experimental infections will be used for evaluation of vector competence of different sand fly populations; localization of parasites and Leishmania morphotypes in sand fly gut will be recorded,   the intensity of experimental infections will be compared by Q-PCR and optical microscopy.

Studies of exposure to sand fly bites will pursue the development of sensitive and specific ELISA test based on human (and/or animal) antibodies against sand fly saliva. We would like to know if the antibody response correlates with numbers of sand flies inside houses and how long antibodies persist after sand fly season under natural conditions of exposure. Anti-saliva antibodies could be used also as a risk marker of Leishmania transmission. A positive association between the level of IgG antibodies against vector sand fly saliva and the probability of developing leishmaniasis (CL) has been documented in humans. In the Old World, no similar study has been done for the visceral form of disease. Detecting of anti-P. orientalis saliva antibodies in human serum samples will also allow us to associate the level of host exposure with the status of Leishmania donovani infection (measured by rk39 dip stick and other methods). Leishmania seroconversion of local people will be monitored continuously and anamnesis will be ascertained using questionnaires. In addition, study on anti-saliva antibodies will serve to evaluate intervention trials and control programmes against sand flies. It will improve our understanding of infectious disease epidemiology and may serve as a model for future studies on other vector-host combinations.

Personnel

1. Petr Volf, Group leader and Co-Principal Investigator volf@cesnet.cz
2. Jan Votypka, Co-Principal Investigator vapid@natur.cuni.cz
3.  Milena Svobodova Associate Researcher milena@natur.cuni.cz
4. Vit Dvorak, Associate Researcher icejumper@seznam.cz

Petr Volf’s Vector Biology group is at the Department of Parasitology in Charles University Prague. His group has been studying vector-parasite-host interactions with an emphasis on sand fly-Leishmania,  for many years

Selected Publications

1. Drahota J., Lipoldova M., Volf P., Rohousova I. Specificity of anti-saliva immune response in mice repeatedly bitten by Phlebotomus sergenti. Parasite Immunology (2009) 31:766-770
2. Sadlova J., Volf P. Peritrophic matrix of Phlebotomus duboscqi and its kinetics during Leishmania major development Cell And Tissue Research (2009) 337: 313-325
3. Hostomska J., Volfova V., Mu JB, Garfield M, Rohousova I, Volf P, Valenzuela JG, Jochim RC Analysis of salivary transcripts and antigens of the sand fly Phlebotomus arabicus BMC Genomics (2009) 10: 282
4. Jecna L., Svarovska A., Besteiro S., Mottram JC, Coombs GH, Volf P Inhibitor of Cysteine Peptidase Does Not Influence the Development of Leishmania mexicana in Lutzomyia longipalpis. Journal Of Medical Entomology (2009) 46: 605-609
5. Svobodova M., Alten B., Zidkova L., Dvorak V., Hlavackova J., Myskova J., Seblova V., Kasap O. E., Belen A., Votypka J., Volf P. (2009) Cutaneous leishmaniasis caused by Leishmania infantum transmitted by Phlebotomus tobbi. International Journal for Parasitology 39: 251–256.
6. Volf P, Myskova J. Sand flies and Leishmania: specific versus permissive vectors. Trends Parasitol. (2007) 23:91-2.
7. Myskova J., Svobodova M., Beverley S. M. , Volf P. A lipophosphoglycan-independent development of Leishmania in permissive sand flies. Microbes Infect. (2007) 9: 317-24
8. Volf P, Benkova I, Myskova J, Sadlova J, Campino L, Ravel C. Increased transmission potential of Leishmania major/Leishmania infantum hybrids. Int J Parasitol. (2007) 37:589-93.
9. Benkova I, Volf P. Effect of temperature on metabolism of Phlebotomus papatasi (Diptera: Psychodidae). J Med Entomol.(2007) 44:150-4.
10. Svobodova M, Volf P, Votypka J. (2006) Experimental transmission of Leishmania tropica to hyraxes (Procavia capensis) by the bite of Phlebotomus arabicus. Microbes Infect. (2006) 8:1691-4
11. Havelkova H, Badalova J, Svobodova M, Vojtiskova J, Kurey I, Vladimirov V, Demant P, Lipoldova M. (2006) Genetics of susceptibility to leishmaniasis in mice: four novel loci and functional heterogeneity of gene effects. Genes Immun. 7: 220-33.
12. Svobodova M., Votypka J., Peckova J., Dvorak V., Nasereddin A., Baneth G., Sztern J., Kravchenko V., Orr A., Meir D., Schnur L. F., Volf P., Warburg A. (2006) Distinct Transmission Cycles of Leishmania tropica in 2 Adjacent Foci, Northern Israel. Emerging Infectious Diseases 12: 1860-8
13. Dvorak V, Aytekin AM, Alten B, Skarupova S, Votypka J, Volf P. A comparison of the intraspecific variability of Phlebotomus sergenti Parrot, 1917 (Diptera: Psychodidae). J Vector Ecol. (2006) 31:229-38.
14. Rohousova I, Volf P. Sand fly saliva: effects on host immune response and Leishmania transmission. Folia Parasitol (Praha). (2006) 53161-71. Review.
15. Kato H, Anderson JM, Kamhawi S, Oliveira F, Lawyer PG, Pham VM, Sangare CS, Samake S, Sissoko I, Garfield M, Sigutova L, Volf P, Doumbia S, Valenzuela JG. High degree of conservancy among secreted salivary gland proteins from two geographically distant Phlebotomus duboscqi sandflies populations (Mali and Kenya). BMC Genomics. (2006) 7:226.
16. Rohousova I., Ozensoy S., Ozbel Y., Volf P. (2005) Detection of species-specific antibody response of humans and mice bitten by sand flies. Parasitology 130: 443-449
17. Rohousova I., Volf P., and Lipoldova M. (2005) Modulation of murine cellular immune response and cytokine production by salivary gland lysate of three sand fly species. Parasite Immunology 27: 469-473
18. Thiakaki M., Rohousova I., Volfova V., Volf P., Chang K.P., and Soteriadou K., (2005) Sand fly species-specificity of saliva-mediated protective immunity in Leishmania amazonensis-BALB/c mouse model. Microbes and Infection 7: 760-766
19. Hajmova M., Chang K.P., Kolli B., Volf P. (2004) Down-regulation of gp63 in Leishmania amazonensis reduces its early development in Lutzomyia longipalpis. Microbes and Infection 6: 646-649
20. Volf P., Hajmova M., Sadlova J., Votypka J. (2004) Blocked stomodeal valve of the insect vector: similar mechanism of tranmsission in two trypanosomatid models. Int. J. Parasitol. 34: 1221-1227
21. Soares R.P.P., Barron T., McKoy-Simandle K., Svobodova M., Warburg A., Turco S.J. (2004) Leishmania tropica: intraspecific polymorphisms in lipophosphoglycan correlate with transmission by different Phlebotomus species. Exp. Parasitol. 107: 105-114
22. Boulanger N., Lowenberger D., Volf P., Ursic R., Sigutova L., Sabatier L., Svobodova M., Beverley S.M., Spath G., Brun R., Pesson B., Bulet P. (2004) Characterization of a defensin from tha sand fly Phlebotomus duboscqi induced by challenge with bacteria or the protozoan parasite Leishmania major. Infect. Immun. 72: 7140-7146
23. Svobodova M., Sadlova J., Chang K.P. and Volf P. (2003): Spatial distribution and feeding preferences of Phlebotomus sergenti and P. papatasi sand flies in cutaneous leishmaniasis focus of Sanliurfa, Turkey. Am. J. Trop. Med. Hyg. 68: 6-9
24. Svobodova M., Votypka J., Nicolas L., Volf P. (2003) Leishmania tropica in the black rat (Rattus rattus): persistance and transmission from asymptomatic host to sand fly vector Phlebotomus sergenti. Microbes and Infection 5: 361-364
25. Svobodova M., Votypka J. (2003) Experimental transmission of Leishmania tropica to hamsters and mice by the bite of Phlebotomus sergenti. Microbes and Infection 5: 471-474
    Jacobson R.L., Eisenberger C., Svobodova M. et al. (2003) Outbreak of cutaneous leishmaniasis in northern Israel. J. Inf. Dis. 188: 1065-73
26. Sadlova J, Hajmova M, Volf P. (2003) Phlebotomus (Adlerius) halepensis vector competence for Leishmania major and Le. tropica. Med. Vet. Entomol. 17: 244-250
27. Depaquit J., Ferte H., Leger N., Lefranc F., Alves-Pirez C., Hanafi H., Maroli M., Morillas-Marquez F., Rioux J.A., Svobodova M. and Volf P.(2002): ITS2 sequences heterogeneity in Phlebotomus sergenti and P. similis: possible consequences in their ability to transmit Leishmania tropica. Int. J. Parasitol. 32: 1123-1131.
28. Lipoldova M., Svobodova M., Havelkova H., Krulova M., Badalova J., Nohynkov? E., Hurt A.A.M., Schlegel D., Volf P. and Demant P. (2002): Mouse genetic model for clinical and immunological heterogeneity of leishmaniasis. Immunogenetics 54: 174-183.
29. Badalova J., Svobodova M., Havelkova H., Vladimirov V., Vojtiskova J., Engova J., Pilcik T., Volf P., Demant P. and Lipoldova M. (2002): Separation and mapping genes that control IgE level in Leishmania major infected mice. Genes and Immunity 3: 183-195.
30. Votypka J., Obornik M., Volf P., Svobodova M. and Lukes J. (2002): Trypanosoma avium of raptors (Falconiformes): phylogeny and identification of vectors. Parasitology 125: 253-263.
31. Volf P., Skarupova S. and Man P. (2002): Characterization of the lectin from females of Phlebotomus duboscqi sand flies. Eur. J. Biochem. 269: 6294-6301.
32. Volf P., Rohousova I. (2001): Species-specific antigens in salivary glands of phlebotomine sandflies. Parasitology 122: 37-41.
33. Volf P., Svobodova M. and Dvorakova E. (2001): Bloodmeal digestion and Leishmania major infections in Phlebotomus duboscqi: effect of carbohydrates inhibiting midgut lectin activity. Med. Vet. Entomol. 15: 281-286.
34. Volf P., Ozbel Y., Akkafa F., Svobodova M., Votypka J. and Chang K.P. (2001): Sand flies (Diptera: Phlebotominae) in Sanliurfa, Turkey: relationship of Phlebotomus sergenti with the epidemic of anthroponotic cutaneous leishmaniasis. J. Med.Entomol.39:12-15.
35. Volf P., Tesarova P., Nohynkova E. (2000): Salivary proteins and glycoproteins in sandflies of various species, sex and age. Medical and Veterinary Entomology 14: 251-256.

Vit Dvorak (front) and Jan Votypka collecting sand flies inside a house in Turkey

Members of petr Volf’s Laboratory (Milena Svobodova [standing front-left]; Jan Votypka [sitting front row -left], Petr Volf [sitting back row-center], Vit Dvorak [standing back row-right]

Volcani Center, Israel