Occurrence of Phlebotomine sand flies (Diptera: Psychodidae) in the northeastern plain of Italy

Abstract

Background Recent climate and environmental changes have resulted in the geographical expansion of Mediterranean Leishmania infantum vectors towards northern latitudes and higher altitudes in different European countries, including Italy, where new foci of canine leishmaniasis have been observed in the northern part of the country. Northern Italy is also an endemic area for mosquito-borne diseases. During entomological surveillance for West Nile virus, mosquitoes and other hematophagous insects were collected, including Phlebotomine sand flies. In this study, we report the results of Phlebotomine sand fly identification during the entomological surveillance conducted from 2017 to 2019. Methods The northeastern plain of Italy was divided by a grid with a length of 15 km, and a CO2-CDC trap was placed in each geographical unit. The traps were placed ~ 15 km apart. For each sampling site, geographical coordinates were recorded. The traps were operated every two weeks, from May to November. Sand flies collected by CO2-CDC traps were identified by morphological and molecular analysis. Results From 2017 to 2019, a total of 303 sand flies belonging to the species Phlebotomus perniciosus (n = 273), Sergentomyia minuta (n = 5), P. mascittii (n = 2) and P. perfiliewi (n = 2) were collected, along with 21 unidentified specimens. The trend for P. perniciosus collected during the entomological surveillance showed two peaks, one in July and a smaller one in September. Sand flies were collected at different altitudes, from −2 m above sea level (a.s.l.) to 145 m a.s.l. No correlation was observed between altitude and sand fly abundance. Conclusions Four Phlebotomine sand fly species are reported for the first time from the northeastern plain of Italy. Except for S. minuta, the sand fly species are competent vectors of Leishmania parasites and other arboviruses in the Mediterranean Basin. These findings demonstrate the ability of sand flies to colonize new environments previously considered unsuitable for these insects. Even though the density of the Phlebotomine sand fly population in the plain areas is consistently lower than that observed in hilly and low mountainous areas, the presence of these vectors could herald the onset of epidemic outbreaks of leishmaniasis and other arthropod-borne diseases in areas previously considered non-endemic.

Exposure to Major Vector-Borne Diseases in Dogs Subjected to Different Preventative Regimens in Endemic Areas of Italy

“…Although only a single dog tested positive for anti- L. infantum igG in northern Italy (site A), this finding confirms the stable presence of this protozoan in the north of the country, where the vectors of L. infantum are now endemic [ 56 , 57 ]. Colonization by sandflies and dog relocation from South to North Italy contributed to the establishment of the parasite, which should nowadays also be considered endemic in northern areas of Italy [ 58 , 59 ]. Accordingly, endemic foci in Veneto (site A) have been previously described [ 56 ].…”

Monitoring of Insecticide Resistance Mutations and Pathogen Circulation in Sand Flies from Emilia-Romagna, a Leishmaniasis Endemic Region of Northern Italy

“…L. infantum has been exclusively documented in the surveyed regions in the past, based on specific molecular typing, implying that the isolates herein also belong to this species. In 2012, after almost 30 years, human leishmaniasis re-emerged in northern Italy, with P. perfiliewi “driving” several outbreaks (of canine leishmaniasis, as well) so far [ 29 , 30 , 31 , 32 ]. Interestingly, Calzolari et al, 2019 [ 31 ] described that L. infantum strains circulating in ER differ genetically based on their reservoir host (humans or dogs), suggesting that two distinct but overlapping Leishmania transmission cycles may occur in the region.…”

Distribution of Phlebotomine Sand Flies (Diptera: Psychodidae) in the Lombardy Region, Northern Italy

“…Ph. mascitti is a suspected vector of L. infantum [ 6 , 32 ]. However, its vector competence has still not been experimentally verified, although the repeated signals of leishmaniasis cases in Germany and Austria [ 33 , 34 ] may indicate the possible role of Ph.…”