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

Alice Michelutti,Giulia Simonato,Michela Bertola,Silvia Ravagnan,Fabrizio Montarsi,Federica Toniolo,Marika Grillini

doi:10.1186/s13071-021-04652-2

Alice Michelutti, Giulia Simonato + Show 5 more

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https://doi.org/10.1186/s13071-021-04652-2

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Abstract

BackgroundRecent 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.MethodsThe 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.ResultsFrom 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.ConclusionsFour 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.Graphical

Highlights

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
Entomological surveys conducted in these regions have confirmed the geographical expansion of Phlebotomine sand flies to northern latitudes: P. perniciosus was the most widespread species in both pre-Alpine and pre-Apennine territories, while P. neglectus was present only in pre-Alpine and P. perfiliewi in pre-Apennine sites [14]
A total of 303 sand flies belonging to the species P. perniciosus (n = 273), S. minuta (n = 5), P. mascittii (n = 2) and P. perfiliewi (n = 2) were collected

Summary

Introduction

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. Entomological surveys conducted in these regions have confirmed the geographical expansion of Phlebotomine sand flies to northern latitudes: P. perniciosus was the most widespread species in both pre-Alpine and pre-Apennine territories, while P. neglectus was present only in pre-Alpine and P. perfiliewi in pre-Apennine sites [14] These studies confirmed the most suitable habitat for these vectors is represented by hilly and low mountainous areas [11,12,13, 15, 18,19,20]

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