We quantified Leishmania infantum parasites transmitted by natural vectors for the first time. Both L. infantum strains studied, dermotropic CUK3 and viscerotropic IMT373, developed well in Phlebotomus perniciosus and Lutzomyia longipalpis. They produced heavy late-stage infection and colonized the stomodeal valve, which is a prerequisite for successful transmission. Infected sand fly females, and especially those that transmit parasites, feed significantly longer on the host (1.5-1.8 times) than non-transmitting females. Quantitative PCR revealed that P. perniciosus harboured more CUK3 strain parasites, while in L. longipalpis the intensity of infection was higher for the IMT373 strain. However, in both sand fly species the parasite load transmitted was higher for the strain with dermal tropism (CUK3). All but one sand fly female infected by the IMT373 strain transmitted less than 600 promastigotes; in contrast, 29% of L. longipalpis and 14% of P. perniciosus infected with the CUK3 strain transmitted more than 1000 parasites. The parasite number transmitted by individual sand flies ranged from 4 up to 4.19×10(4) promastigotes; thus, the maximal natural dose found was still about 250 times lower than the experimental challenge dose used in previous studies. This finding emphasizes the importance of determining the natural infective dose for the development of an accurate experimental model useful for the evaluation of new drugs and vaccines.

Department of Parasitology Charles University Prague Czech Republic

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WHO. 2010. Working to overcome the global impact of neglected tropical diseases. Available: http://www.who.int/neglected_diseases/2010report/NTD_2010report_web.pdf. Accessed 2 November 2010.

Gradoni L, Gramiccia M. Leishmania infantum tropism: strain genotype or host immune status? Parasitol Today. 1994;10:264–267. PubMed

Campino L, Abranches P. Cutaneous leishmaniasis. Unusual disease in Portugal? Acta Med Port. 2002;15:387–390. PubMed

García-Almagro D. Cutaneous leishmaniasis. Actas Dermosifiliogr. 2005;96:1–24. PubMed

Lima H, Rodríguez N, Feliciangeli M, Barrios M, Sosa A, et al. Cutaneous leishmaniasis due to Leishmania chagasi/Le. infantum in an endemic area of Guarico State, Venezuela. Trans R Soc Trop Med Hyg. 2009;103:721–726. PubMed

Svobodova M, Alten B, Zidkova L, Dvorak V, Hlavackova J, et al. Cutaneous leishmaniasis caused by Leishmania infantum transmitted Phlebotomus tobbi. . Int J Parasitol. 2008;39:251–256. PubMed

Titus R, Ribeiro J. Salivary gland lysates from the sand fly Lutzomyia longipalpis enhance Leishmania infectivity. Science. 1988;239:1306–1308. PubMed

Rogers M, Chance M, Bates P. The role of promastigote secretory gel in the origin and transmission of the infective stage of Leishmania mexicana by the sandfly Lutzomyia longipalpis. . Parasitology. 2002;124:495–507. PubMed

Rohousova I, Volf P. Sandfly saliva: effects on host immune response and Leishmania transmission. Folia Parasitol. 2006;53:161–171. PubMed

Melby P, Yang Y, Cheng J, Zhao W. Regional differences in the cellular immune response to experimental cutaneous or visceral infection with Leishmania donovani. Infect Immun. 1998;66:18–27. PubMed PMC

Rolão N, Melo C, Campino L. Influence of the inoculation route in BALB/c mice infected by Leishmania infantum. Acta Trop. 2004;90:123–126. PubMed

Ahmed S, Colmenares M, Soong L, Goldsmith-Pestana K, Munstermann L, et al. Intradermal infection model for pathogenesis and vaccine studies of murine visceral leishmaniasis. Infect Immun. 2003;71:401–410. PubMed PMC

Maia C, Rolão N, Nunes M, Campino L. Infectivity of Leishmania infantum treated with amphotericin B plus Phlebotomus salivary gland in BALB/c mice. Int J Integr Biol. 2009;6:105–111.

Kimblin N, Peters N, Debrabant A, Secundino N, Egen J, et al. Quantification of the infectious dose of Leishmania major transmitted to the skin by single sand flies. Proc Natl Acad Sci USA. 2008;105:10125–10130. PubMed PMC

Rogers M, Corware K, Müller I, Bates P. Leishmania infantum proteophosphoglycans regurgitated by the bite of its natural sand fly vector, Lutzomyia longipalpis, promote parasite establishment in mouse skin and skin-distant tissues. Microbes Infect. 2010;12:875–879. PubMed

Killick-Kendrick R. Phlebotomine vectors of the leishmaniases: a review. Med Vet Entomol. 1990;4:1–24. PubMed

Warburg A, Schlein Y. The effect of post-bloodmeal nutrition of Phlebotomus papatasi on the transmission of Leishmania major. Am J Trop Med Hyg. 1986;35:926–930. PubMed

Schlein Y. Leishmania and sandflies: interactions in the life cycle and transmission. Parasitol Today. 1993;9:255–258. PubMed

Volf P, Hajmova M, Sadlova J, Votypka J. Blocked stomodeal valve of the insect vector: Similar mechanism of transmission in two trypanosomatid models. Int J Parasitol. 2004;34:1221–1227. PubMed

Rogers M, Hajmová M, Joshi M, Sadlova J, Dwyer D, et al. Leishmania chitinase facilitates colonization of sand fly vectors and enhances transmission to mice. Cell Microbiol. 2008;10:1363–1372. PubMed PMC

Rogers M, Bates P. Leishmania manipulation of sand fly feeding behaviour results in enhanced transmission. PLoS Pathog. 2007;3(6):e91. doi: 10.1371/journal.ppat.0030091. PubMed DOI PMC

Maia C, Nunes M, Cristóvão J, Campino L. Experimental canine leishmaniasis: clinical, parasitological and serological follow-up. Acta Trop. 2010;116:193–199. PubMed

Volf P, Volfova V. Establishment and maintenance of sand fly colonies. J Vector Ecol. In press 2011 PubMed

Cihakova J, Volf P. Development of different Leishmania major strains in the vector sandflies Phlebotomus papatasi and P. duboscqi. Annals of tropical Medicine and Parasitology. 1997;91:267–279. PubMed

Mary C, Faraut F, Lascombe L, Dumon H. Quantification of Leishmania infantum DNA by a realtime PCR assay with high sensitivity. J Clin Microbiol. 2004;42:5249–5255. PubMed PMC

Myskova J, Votypka J, Volf P. Leishmania in sand flies: comparison of quantitative polymerase chain reaction with other techniques to determine the intensity of infection. J Med Entomol. 2008;45:133–138. PubMed

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Experimental transmission of Leishmania (Mundinia) parasites by biting midges (Diptera: Ceratopogonidae)

Central Asian Rodents as Model Animals for Leishmania major and Leishmania donovani Research

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