Entomological Surveillance in Former Malaria-endemic Areas of Southern Italy.

Donato Antonio Raele,Ilaria Vasco,Maria Assunta Cafiero,Francesco Severini,Francesco Desiante,Luciano Toma,Pasquale Miccolis,Daniela Boccolini,Pietrangelo Salerno,Ettore Franco,Michela Menegon,Vincenzo Nola,Marco Di Luca

doi:10.3390/pathogens10111521

Abstract

Malaria still represents a potential public health issue in Italy, and the presence of former Anopheles vectors and cases imported annually merit continuous surveillance. In areas no longer endemic, the concurrent presence of gametocyte carriers and competent vectors makes re-emergence of local transmission possible, as recently reported in Greece. In October 2017, due to the occurrence of four suspected introduced malaria cases in the province of Taranto (Apulia region), entomological investigations were performed to verify the involvement of local anopheline species. In 2019–2020 entomological surveys were extended to other areas historically prone to malaria between the provinces of Taranto and Matera and the province of Foggia (Gargano Promontory). Resting mosquitoes were collected in animal shelters and human dwellings, larvae were sampled in natural and artificial breeding sites, and specimens were both morphologically and molecularly identified. A total of 2228 mosquitoes were collected, 54.3% of which were anophelines. In all the investigated areas, Anopheles labranchiae was the most widespread species, while Anopheles algeriensis was predominant at the Gargano sites, and Anopheles superpictus and Anopheles plumbeus were recorded in the province of Matera. Our findings showed a potentially high receptivity in the surveyed areas, where the abundance of the two former malaria vectors, An. labranchiae and An. superpictus, is related to environmental and climatic parameters and to anthropic activities.

Highlights

Malaria transmission in Italy was associated primarily with the presence of two vector species, Anopheles labranchiae Falleroni, 1926, and Anopheles sacharovi Favre, 1903, both belonging to the Anopheles maculipennis Meigen complex
Nineteen species belonging to six genera were identified in the total sample: Aedes albopictus (Skuse, 1894), Aedes caspius (Pallas, 1771), Aedes detritus (Haliday, 1833), Aedes geniculatus (Olivier, 1791), Aedes vexans (Meigen, 1830), Anopheles algeriensis Theobald, 1903, Anopheles plumbeus Stephens, 1828, Anopheles labranchiae Falleroni, 1926, Anopheles superpictus Grassi, 1899, Culex hortensis Ficalbi, 1889, Culex laticinctus Edwards, 1913, Culex pipiens Linnaeus, 1758, Culex territans Walker, 1856, Culex theileri Theobald, 1903, Culex univittatus Theobald, 1901, Culiseta annulata (Schrank, 1776), Culiseta longiareolata (Macquart, 1838), Coquillettidia richiardii (Ficalbi, 1899) and Uranotaenia unguiculata (Edwards, 1913)
As our study focused on Anopheles, the results of collections by site, year and capture method refer to this genus only (Table 3)

Summary

Introduction

In countries no longer endemic, primarily those bordering the Mediterranean basin where malaria was eradicated, the concurrent presence of gametocyte carriers and competent mosquitoes may favor the re-emergence of sporadic autochthonous cases but may make local transmissions sustainable, as recently reported in Greece [4,5]. Malaria transmission in Italy was associated primarily with the presence of two vector species, Anopheles labranchiae Falleroni, 1926, and Anopheles sacharovi Favre, 1903, both belonging to the Anopheles maculipennis Meigen complex. The first species, which is still present in Italy in scattered foci, was considered the main vector along the central and southern coasts and in Sicily and Sardinia. Following the malaria eradication campaign (1947–1951), the abundance of An. sacharovi was greatly reduced, and this species has not been found in the country since the 1960s, probably because of the progressive disappearance and/or modification of its larval habitats [8,9,10,11]

Methods

Results

Discussion

Conclusion