Serological Evidence of USUTU Virus Occurrence in North‐Eastern Italy

Lelli, Rossella; Savini, Giovanni; Teodori, Liana; Filipponi, G.; Gennaro, Annapia Di; Leone, Alessandra; Gialleonardo, Luigina Di; Venturi, L.; Caporale, V.

doi:10.1111/j.1863-2378.2008.01146.x

Cited by 53 publications

(51 citation statements)

References 33 publications

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“…Lelli et al, 2008;Manarolla et al, 2010;Tamba et al, 2011; Vázquez et al, 2011;Cerutti et al, 2012;Ravanini et al, 2012;Buchebner et al, 2013;Calzolari et al, 2013a; Höfle et al, 2013). In Europe, USUV has been recognized as a candidate human pathogen in Austria (Weissenböck et al, 2007), Italy (Cavrini et al, 2009;Pecorari et al, 2009;Savini et al, 2011;Gaibani et al, 2012Gaibani et al, , 2013Pierro et al, 2013) and Croatia (Vilibic-Cavlek et al, 2014), but the pathogenicity for humans still requires further assessment.…”

Section: Introductionmentioning

confidence: 99%

Wide detection of Aedes flavivirus in north-eastern Italy – a European hotspot of emerging mosquito-borne diseases

Grisenti

Vázquez

Herrero

et al. 2015

Journal of General Virology

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The pattern of flavivirus infection in mosquitoes belonging to the genera Aedes and Culex collected in two regions of north-eastern Italy (Trentino and Veneto) was assessed. Mosquitoes were collected during 2012 and screened for flaviviruses using a generic reverse transcriptionnested-PCR targeted on a region of the non-structural NS5 gene. The phylogenetic analysis was performed on a fragment of~1000 bp. Virus isolation was attempted in C6/36 insect cell lines and the infected cell cultures were studied by electron microscopy. We detected a wide distribution of Aedes flavivirus (AeFV) in Aedes albopictus, with higher infection prevalence in Trentino than in Veneto. In Culex pipiens collected in Veneto, we detected a new sequence of an insect-specific flavivirus and one of Usutu virus. Interestingly, we detected AeFV in C. pipiens, for the first time to our knowledge, in both regions. Viral isolation in cell culture was successful for AeFV. AeFV sequences found in Veneto showed a high percentage of similarity to those detected in Trentino and to those previously reported in other areas of northern Italy. Co-infections with different flaviviruses were not detected. INTRODUCTIONThe genus Flavivirus (family Flaviviridae) comprises .70 viruses that, according to their mechanism of transmission, are included in one of the following three groups: (1) those infecting a range of vertebrate hosts through mosquito or tick bites, called 'arthropod-borne viruses', (2) those spread without a known vector, presumed to be limited to infecting vertebrates only, and (3) those apparently limited to insects alone, called 'insect-specific flaviviruses' (ISFs) (Ishikawa & Konishi, 2011;Huhtamo et al., 2012 and references therein). The flavivirus genome contains genes coding for three structural proteins (capsid, premembrane and envelope) and seven non-structural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5) (Lindenbach et al., 2006). Regions encoding envelope, NS3 and NS5 are the most frequently used for phylogenetic analysis of flaviviruses. The inclusion of ISFs in the genus Flavivirus is supported by similarities with other flaviviruses in terms of genomic organization, polyprotein hydropathy profiles and cleavage sites, but they are not able to replicate in mammalian cells and they have been isolated only in mosquito-derived cells (Kuno, 2007;Hoshino et al., 2009;Bolling et al., 2011;Cook et al., 2012;Haddow et al., 2013).The 'arthropod-borne viruses' group includes some important emerging human and animal pathogens, such 3These authors contributed equally to this work.The GenBank/EMBL/DDBJ accession numbers for representative sequences obtained in this work are KM871198-KM871202. Lelli et al., 2008;Manarolla et al., 2010;Tamba et al., 2011; Vázquez et al., 2011;Cerutti et al., 2012;Ravanini et al., 2012;Buchebner et al., 2013;Calzolari et al., 2013a; Höfle et al., 2013). In Europe, USUV has been recognized as a candidate human pathogen in Austria (Weissenböck et al., 2007), Italy (Cavrini et al., 2009;Pecorari et al., ...

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Section: Introductionmentioning

confidence: 99%

Wide detection of Aedes flavivirus in north-eastern Italy – a European hotspot of emerging mosquito-borne diseases

Grisenti

Vázquez

Herrero

et al. 2015

Journal of General Virology

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“…64 However, further studies conducted in the UK did not confirm USUV circulation in the country. 65,66 Seroconversion was also observed in Italy in the summer of 2005 67 and in 2007-2008, 68 although no virus could be rescued from these animals, and in France in 2009-2010, even though cross-reactivity with WNV could not be discarded. 71 Although the drop in screened positive birds in the region during the course of the sampled years may be due to herd immunity acquired in previous seasons, the study showed that the virus spread from the original area of emergence to surrounding areas of the country.…”

Section: µMmentioning

confidence: 96%

Usutu virus: current knowledge and future perspectives

Saiz¹,

Blázquez²

2017

VAAT

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Abstract:The Flavivirus genus (Flaviviridae family) contains important pathogens such as yellow fever virus, Japanese encephalitis virus, St Louis encephalitis virus, West Nile virus, Usutu virus (USUV), Zika virus, and dengue virus, many of which constitute a worrisome threat to global human and animal health. USUV is transmitted by mosquitoes and, as any other flavivirus, is an enveloped plus-strand RNA virus. The virus was first isolated from Culex neavei mosquitoes in South Africa in 1959 near the Usutu River, from where it takes its name. Since then, the virus was confined to Africa until its first detection in Austria in 2001, although it was probably present in Europe since 1996 or even earlier. After that, USUV has spread throughout Europe, causing a considerable mortality among birds and a few neurologic cases in humans. The main USUV natural hosts are birds, but infection has also been reported in other vertebrate species, including humans. The fast spread of the virus through the continent, the relatively high mortality caused in birds, and the recent neuroinvasive human cases related to USUV infection reported in Europe have raised serious concerns about its possible consequences for public health. Here, an updated review of current knowledge about this emerging pathogen is presented. Keywords: Usutu virus, flavivirus, host cell-virus interactions, surveillance, prophylaxis Biology of the virus Molecular classification and phylogenyUsutu virus (USUV) is a member of the Flavivirus genus within the Flaviviridae family ( Figure 1A). In 2004, the complete genomic sequences of two USUV strains, one African (South Africa-1959) and one European (Vienna-2001), were used to build a phylogenetic tree. These two strains showed a 97% and 99% homology at the nucleotide (nt) and amino acid (aa) level, respectively.1 Both strains were closely related to Murray valley encephalitis virus (73% and 82% nt and aa similarity), Japanese encephalitis virus (71% and 81% nt and aa similarity), and to West Nile virus (WNV; 68% and 75% nt and aa similarity). Nowadays, dozens of complete sequences are available in the data banks. In a recent study, the sequence identity among seven USUV strains was 96%-99% and 99% at the nt and aa levels, respectively.2 The only exception was a 1969 isolate from Central African Republic (CAR-1969) that presented homologies of 81% and 94% at the nt and aa levels with other African sequences ( Figure 1B). Due to these differences, it has been suggested that CAR-1969 formed an USUV subtype strain.3 A comparison with the original South African SAAR-1776 strain showed that the mutations found among different European and African strains were scattered throughout the genome, with some unique substitutions and some that were present

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“…In northern Italy, antibodies against USUV were found in sera of sentinel chickens from 2005 and 2007 [45,46]. Also in Italy, sera of horses in the Tuscany region and North-East Italy collected in 2008 and 2009 were positive for USUV-specific antibodies [47].…”

Section: Current Knowledge About the Pathogenmentioning

confidence: 99%

Usutu Virus

2013

Transfus Med Hemother

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Serological Evidence of USUTU Virus Occurrence in North‐Eastern Italy

Cited by 53 publications

References 33 publications

Wide detection of Aedes flavivirus in north-eastern Italy – a European hotspot of emerging mosquito-borne diseases

Wide detection of Aedes flavivirus in north-eastern Italy – a European hotspot of emerging mosquito-borne diseases

Usutu virus: current knowledge and future perspectives

Usutu Virus

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