Natural infection of Phlebotomus (Larroussius) langeroni (Diptera: Psychodidae) with Leishmania infantum in Tunisia

Abstract

Phlebotomine sand flies were captured from an active transmission focus of sporadic cutaneous leishmaniasis, caused by Leishmania infantum, in El Kef region, northern Tunisia. Both Phlebotomus perniciosus and P. langeroni were found. Phlebotomus langeroni females showed a statistically significant intradomiciliary dominance (P<0.01 for the 2003 and 2004 seasons) when compared to animal shelters. During the 2003 season, dissection of collected female specimens showed the presence of flagellates within the digestive tracts of two P. perniciosus among 1086 observed, but none in 232 P. langeroni. Amplification of kinetoplast minicircles of Leishmania parasites was applied to DNA samples extracted from 298 frozen females including 249 P. perniciosus, 36 P. langeroni, 5 P. longicuspis and 8 P. perfiliewi and revealed by radioactive probe hybridization. Two P. langeroni females showed a signal of the size expected for L. infantum (800bp) indicating infection with these parasites. However, this PCR-hybridization method failed to identify any positive P. perniciosus females in pools of specimens. These results show for the first time the natural infection of P. langeroni with L. infantum in Tunisia, and support the existence of different L. infantum transmission cycles in Tunisia, with a potential role for P. langeroni as a vector.

Retrospective Analysis of Leishmaniasis in Central Tunisia: An Update on Emerging Epidemiological Trends

“…This knowledge greatly benefited of the availability of techniques used in typing isolates obtained from humans or from reservoirs and sandflies. In this respect, IEE or molecular techniques allowed a more precise identification of the Leishmania at the species, zymodeme and genomic (schizodeme) level (Ben Hammouda et al, 2000;Ben Said et al, 2006;Guerbouj et al, 2007;Guizani et al, 1993Guizani et al, , 1994aGuizani et al, , 1994bGuizani et al, 2002;Hanafi et al, 2001;Kallel et al, 2008b). As far as zymodemes are concerned, it was shown that L. major was much more homogeneous than L. infantum.…”

“…This was attributed to the emergent character of Kairouan foci which may favour and select atypical or rare variants (Aoun et al, 2008;Ben Abda et al, 2009). Involvement of different www.intechopen.com sandfly species in transmission of different L. infantum parasites can not be excluded (Guerbouj et al 2007). It is well established that different sandfly species belonging to the sub-genus Larroussius are involved in the transmission of L. infantum; in Tunisia clear association between sandfly species and bioclimate was demonstrated and presence of species of this subgenus in the different bioclimatic zones allowed explaining the extension of VL (Zhioua et al, 2007).…”

“…An additional advantage of the molecular techniques is their rapidity in that culture of isolates is no more needed. On the other hand, they are much adapted for both diagnostic (PCR, Multiplex PCR, Real time-PCR) and epidemiological (PCR-RFLP, Multiplex PCR, RAPD) purposes (Aoun et al, 2008;Bel Hadj et al, 2002;Ben Said et al, 2006;Chargui et al, 2005;Guerbouj et al, 2007;Guizani et al, 1994aGuizani et al, , 1994bGuizani et al, 2002;Hanafi et al, 2001;Saadi et al, in preparation). In addition, molecular techniques are specific and highly sensitive, allowing identification of parasite species hard to isolate or to maintain in vitro in culture or too scarce to be detected or cultured.…”

“…In this situation, molecular techniques would be much more suitable for this purpose. Using DNA tools, P. langeroni was found infected with L. infantum in an active transmission focus of SCL (Guerbouj et al, 2007). It may be concluded from all these findings that identification and typing of isolates are much needed in order to best assess the epidemiology and to investigate the diversity and changing patterns of leishmaniasis.…”

Leishmaniasis in Tunisia: History and New Insights into the Epidemiology of a Neglected Disease

“…Nevertheless, no L. infantum strain has been isolated from this phlebotomine sand fly species yet. Also, L. infantum DNA was detected from a P. langeroni, P. longicuspis, P. perfiliewi, P. papatasi, and Sergentomyia minuta using molecular tools [45,46]. However, neither parasite isolation from these sand flies species nor L. infantum isoenzymatic identification were carried out in Tunisia yet to confirm their role as vector of L. infantum taxon.…”