RESUMO
A human outbreak of West Nile virus (WNV) infection caused by WNV lineage 2 is ongoing in northern Italy. Analysis of six WNV genome sequences obtained from clinical specimens demonstrated similarities with strains circulating in central Europe and Greece and the presence of unique amino acid changes that identify a new viral strain. In addition, WNV lineage 1 Livenza, responsible for a large outbreak in north-eastern Italy in 2012, was fully sequenced from a blood donor during this 2013 outbreak.
Assuntos
RNA Viral/genética , Febre do Nilo Ocidental/genética , Vírus do Nilo Ocidental/classificação , Vírus do Nilo Ocidental/genética , Sequência de Bases , Surtos de Doenças , Genoma , Humanos , Itália/epidemiologia , Epidemiologia Molecular , Filogenia , Febre do Nilo Ocidental/diagnóstico , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/virologiaRESUMO
We report here the first blood donation positive for West Nile virus (WNV) by nucleic acid amplification testing collected in north-eastern Italy in July 2012.Partial sequencing of the WNV RNA demonstrated identity with a WNV lineage 1a genome identified in the same area in 2011 and divergence from the strain responsible for the outbreak in northern Italy in 200809. These data indicate that WNV activity in northern Italy is occurring earlier than expected and that different WNV strains are circulating.
Assuntos
Doadores de Sangue , RNA Viral/genética , Febre do Nilo Ocidental/virologia , Vírus do Nilo Ocidental/genética , Doenças Endêmicas , Humanos , Itália/epidemiologia , Técnicas de Amplificação de Ácido Nucleico , Filogenia , Vigilância da População , Análise de Sequência , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/genéticaRESUMO
In July-September 2012, one month earlier than in previous years, 13 confirmed human cases of West Nile virus infection were diagnosed in northern Italy, including five with neuroinvasive disease, three with West Nile fever, and five West Nile virus (WNV)-positive blood donors. In nine cases, the presence of the WNV lineage 1a Livenza strain, characterised in 2011, was ascertained. Symptomatic patients had prolonged viruria with high viral load.
Assuntos
Surtos de Doenças , RNA Viral/genética , Febre do Nilo Ocidental/virologia , Vírus do Nilo Ocidental/genética , Doadores de Sangue , Seguimentos , Humanos , Itália/epidemiologia , Vigilância da População/métodos , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência , Carga Viral , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/genética , Vírus do Nilo Ocidental/isolamento & purificaçãoRESUMO
In 2010, for the third consecutive year, human cases of West Nile virus (WNV) infection, including three confirmed cases of neuroinvasive disease and three confirmed cases of West Nile fever, were identified in north-eastern Italy. While in 2008 and 2009 all human cases of WNV disease were recorded in the south of the Veneto region, cases of WNV disease in 2010 additionally occurred in two relatively small northern areas of Veneto, located outside those with WNV circulation in the previous years. WNV IgG antibody prevalence in blood donors resident in Veneto was estimated as ranging from 3.2 per 1,000 in areas not affected by cases of WNV disease to 33.3 per 1,000 in a highly affected area of the Rovigo province. No further autochthonous human cases of WNV disease were notified in Italy in 2010. The recurrence of human cases of WNV infection for the third consecutive year strongly suggests WNV has become endemic in north-eastern Italy.
Assuntos
Anticorpos Antivirais/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Febre do Nilo Ocidental/epidemiologia , Vírus do Nilo Ocidental/isolamento & purificação , Adulto , Idoso , Animais , Anticorpos Antivirais/imunologia , Doadores de Sangue , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Itália/epidemiologia , Masculino , Pessoa de Meia-Idade , Vigilância da População , Prevalência , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sensibilidade e Especificidade , Estudos Soroepidemiológicos , Febre do Nilo Ocidental/diagnóstico , Febre do Nilo Ocidental/virologia , Vírus do Nilo Ocidental/imunologiaRESUMO
We report here an update on human cases of West Nile virus (WNV) infection in Veneto region, northeastern Italy. In addition to two cases of WNV neuroinvasive disease notified through a surveillance programme started in September 2008, further four cases were retrospectively identified (in May 2009) by investigating patients with aseptic meningoencephalitis of unknown aetiology occurring in Veneto region in June-September 2008. All six patients had symptom onset in August-September 2008 and were resident in a wetland area close to the Po river delta in Rovigo province. Further five cases of asymptomatic WNV infection, including four residents of the same area in Rovigo, were identified in a seroprevalence study in farm workers from Veneto region. To date, no human cases have been notified in 2009.
Assuntos
Doenças dos Animais/virologia , Meningoencefalite/virologia , Vigilância da População , Febre do Nilo Ocidental , Vírus do Nilo Ocidental/isolamento & purificação , Adulto , Idoso , Idoso de 80 Anos ou mais , Doenças dos Animais/epidemiologia , Animais , Feminino , Cavalos , Humanos , Itália/epidemiologia , Masculino , Meningoencefalite/líquido cefalorraquidiano , Meningoencefalite/epidemiologia , Pessoa de Meia-Idade , Estudos Retrospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Estudos Soroepidemiológicos , Febre do Nilo Ocidental/sangue , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/virologia , Vírus do Nilo Ocidental/imunologia , Adulto JovemRESUMO
In 2009, six new human cases of West Nile neuroinvasive disease (WNND) were identified in Veneto region, following the six cases already reported in 2008. A human West Nile virus (WNV) isolate was obtained for the first time from an asymptomatic blood donor. Whole genome sequence of the human WNV isolate showed close phylogenetic relatedness to the Italy-1998-WNV strain and to other WNV strains recently isolated in Europe, with the new acquisition of the NS3-Thr249Pro mutation, a trait associated with avian virulence, increased virus transmission, and the occurrence of outbreaks in humans.
Assuntos
Sequência de Bases , Genoma , Vírus do Nilo Ocidental/genética , Vírus do Nilo Ocidental/isolamento & purificação , Sequência de Aminoácidos , Surtos de Doenças , Humanos , Itália , Dados de Sequência Molecular , Filogenia , Febre do Nilo Ocidental/epidemiologiaRESUMO
In recent years, West Nile virus (WNV) lineage 2 has been spreading and causing disease outbreaks in humans and animals in Europe. In order to characterize viral diversity, we performed full-length genome sequencing of WNV lineage 2 from human samples collected during outbreaks in Italy and Greece in 2013 and 2014. Phylogenetic analysis showed that these WNV lineage 2 genomes belonged to a monophyletic clade derived from a single introduction into Europe of the prototype Hungarian strain. Correlation of phylogenetic data with geospatial information showed geographical clustering of WNV genome sequences both in Italy and in Greece, indicating that the virus had evolved and diverged during its dispersal in Europe, leading to the emergence of novel genotypes, as it adapted to local ecological niches. These genotypes carried divergent conserved amino acid substitutions, which might have been relevant for viral adaptation, as suggested by selection pressure analysis and in silico and experimental modelling of sequence changes. In conclusion, the results of this study provide further information on WNV lineage 2 transmission dynamics in Europe, and emphasize the need for WNV surveillance activities to monitor viral evolution and diversity.
Assuntos
Surtos de Doenças , RNA Viral/genética , Febre do Nilo Ocidental/epidemiologia , Vírus do Nilo Ocidental/classificação , Vírus do Nilo Ocidental/genética , Substituição de Aminoácidos , Evolução Molecular , Genoma Viral , Grécia , Humanos , Itália , Modelos Moleculares , Filogenia , Filogeografia , Análise de Sequência de RNA , Febre do Nilo Ocidental/transmissãoRESUMO
During 2008-2009, several human cases of WNV disease caused by an endemic lineage 1a strain were reported in areas surrounding the Po river in north-eastern Italy. Since 2010, cases have been recorded in nearby northern areas, where, in 2011, both lineage 1a and 2 were detected. We describe here two new WNV complete genome sequences from human cases of WNV infection occurring in 2011 in the Veneto Region. Phylogenetic analysis showed that both genome sequences belonged to lineage 1a and were related to WNV strains of the Western Mediterranean subtype. The novel WNV genomes had high nucleotide and amino acid sequence divergence from each other and from the WNV strain circulating in Italy in 2008-2009. The presence of different WNV strains in a relatively small geographical area is a novel finding with unpredictable impact on human disease that requires further investigation.