Open Access Research

Detection of a new insect flavivirus and isolation of Aedes flavivirus in Northern Italy

David Roiz12*, Ana Vázquez3, Fausta Rosso2, Daniele Arnoldi2, Matteo Girardi2, Laureano Cuevas4, Esperanza Perez-Pastrana4, Mari Paz Sánchez-Seco3, Antonio Tenorio3 and Annapaola Rizzoli2

Author Affiliations

1 Wetland Ecology Department, Doñana Biological Station, CSIC, Sevilla, Spain

2 Biodiversity and Molecular Ecology Department, Research and Innovation Centre - Fondazione Edmund Mach. San Michelle all’Adige, Trento, Italy

3 Laboratory of Arboviruses and Viral Imported Diseases. National Center of Microbiology. Institute of Health “Carlos III”, Majadahonda, Madrid, Spain

4 Electron Microscopy Department, National Center of Microbiology. Institute of Health “Carlos III”, Majadahonda, Madrid, Spain

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Parasites & Vectors 2012, 5:223  doi:10.1186/1756-3305-5-223

Published: 8 October 2012

Abstract

Background

During recent years, numerous novel ‘insect flaviviruses’ have been discovered in natural mosquito populations. In a previous study we described the presence of flavivirus DNA sequences integrated in Aedes albopictus (Asian tiger mosquito) populations from Northern Italy in 2007.

Methods

During 2008 we collected and tested Aedes females for flavivirus presence and developed phylogenetic analysis, virus isolation, electron microscopy studies and RNAse treatments.

Results

We detected a high prevalence of flavivirus in Ae. albopictus (77.5%). The phylogenetic analysis identified the insect flavivirus sequences as Aedes flavivirus (AEFV) recently described in Japan, and that may have been introduced in Italy travelling with the tiger mosquito. Some of these pools grew in C6/36 cells, producing cytopathic effects, and the RNase treatment results showed the presence of the detected sequences in RNA forms. Furthermore, we detected a new insect flavivirus in one pool of Aedes cinereus/geminus mosquitoes. Phylogenetic analysis of this virus shows that it forms a distinct cluster within the clade of insect flavivirus.

Conclusions

This is the first study to report a high prevalence, to describe the seasonal activity and an isolation of the insect flavivirus Aedes flavivirus in Europe. Moreover we describe the detection of a new insect flavivirus detected from Ae. cinereus mosquitoes from Italy. These flavivirus may be common, ubiquitous and diverse in nature and we discuss the implications of the insect flavivirus group in virus evolution and transmission.

Keywords:
Aedes albopictus; Aedes cinereus/geminus; Italy; Aedes flavivirus; Integrated sequences; Insect flavivirus; Non-retroviral integrated RNA viruses