Persistence of phlebotomine Leishmania vectors in urban sites of Catania (Sicily, Italy)

Background: Pioneering research on “Mediterranean Kala-Azar” carried out by Adler and Theodor early in the pastcentury (~1930s) had identified Catania city (Sicily) as a major focus of the disease nowadays known as zoonoticvisceral leishmaniasis (VL). Despite the fact that disease in both humans and dogs has continued to be highlyprevalent in the Catania province up to the present times, research on Leishmania vectors in this urban focus datesback to that distant period. This study aimed to evaluate the persistence and current composition of the sand flyfauna in urban environments of Catania in recent years, 2006 and 2013.Methods: In 2006 fifty-one suitable collecting sites were identified within 44 sub-units of a grid drawn to includethe urban Catania area. In 2013 the survey was restricted to four of the most productive and representative sitesresulting from the 2006 survey. In both periods 3 collections per month were performed using standard sticky trapsset for 3 days in wall holes/cavities along public roads, from the end of April through December.Results: 43/51 sites (84.3%) were found positive for sand flies. The 2006 collections accounted for a total of 4341specimens including six species. Among competent Leishmania vector species, P. perniciosus was the mostprevalent (36.5%) being identified in all sand fly-positive sites, with significant abundance in those of the old citycentre. Other species of interest were P. sergenti (2.5%) and P. neglectus (1.5%). The 2013 survey produced 1130 sandflies, of which 39.5% were P. perniciosus, 1.6% P. sergenti and 0.7% P. neglectus. A search for Leishmania DNA in asmall sample of 72 P. perniciosus females revealed 11% infection prevalence.Conclusions: Our findings from an old urban focus of leishmaniasis demonstrate that phlebotomine sand flies haveadapted fairly well to the drastic environmental changes that have occurred in cities of the Western world in thepast century and still represent a potential risk for Leishmania transmission.