scholarly journals Evolutionary Dynamics of the Lineage 2 West Nile Virus That Caused the Largest European Epidemic: Italy 2011–2018

Viruses ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 814 ◽  
Author(s):  
Carla Veo ◽  
Carla della Ventura ◽  
Ana Moreno ◽  
Francesca Rovida ◽  
Elena Percivalle ◽  
...  

Lineage 2 West Nile virus (WNV) caused a vast epidemic in Europe in 2018, with the highest incidence being recorded in Italy. To reconstruct the evolutionary dynamics and epidemiological history of the virus in Italy, 53 envelope gene and 26 complete genome sequences obtained from human and animal samples were characterised by means of next-generation sequencing. Phylogenetic analysis revealed two Italian strains originating between 2010 and 2012: clade A, which apparently became extinct in 2013–2014, and clade B, which was responsible for the 2018 epidemic. The mean genetic distances in clade B increased over time and with the distance between sampling locations. Bayesian birth-death and coalescent skyline plots of the clade B showed that the effective number of infections and the effective reproduction number (Re) increased between 2015 and 2018. Our data suggest that WNV-2 entered Italy in 2011 as a result of one or a few penetration events. Clade B differentiated mainly as a result of genetic drift and purifying selection, leading to the appearance of multiple locally circulating sub-clades for different times. Phylodynamic analysis showed a current expansion of the infection among reservoir birds and/or vectors.

Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 908 ◽  
Author(s):  
Cécile Beck ◽  
Isabelle Leparc Goffart ◽  
Florian Franke ◽  
Gaelle Gonzalez ◽  
Marine Dumarest ◽  
...  

Since 2015, annual West Nile virus (WNV) outbreaks of varying intensities have been reported in France. Recent intensification of enzootic WNV circulation was observed in the South of France with most horse cases detected in 2015 (n = 49), 2018 (n = 13), and 2019 (n = 13). A WNV lineage 1 strain was isolated from a horse suffering from West Nile neuro-invasive disease (WNND) during the 2015 episode in the Camargue area. A breaking point in WNV epidemiology was achieved in 2018, when WNV lineage 2 emerged in Southeastern areas. This virus most probably originated from WNV spread from Northern Italy and caused WNND in humans and the death of diurnal raptors. WNV lineage 2 emergence was associated with the most important human WNV epidemics identified so far in France (n = 26, including seven WNND cases and two infections in blood and organ donors). Two other major findings were the detection of WNV in areas with no or limited history of WNV circulation (Alpes-Maritimes in 2018, Corsica in 2018–2019, and Var in 2019) and distinct spatial distribution of human and horse WNV cases. These new data reinforce the necessity to enhance French WNV surveillance to better anticipate future WNV epidemics and epizootics and to improve the safety of blood and organ donations.


2019 ◽  
Vol 141 ◽  
pp. 106617 ◽  
Author(s):  
Serafeim C. Chaintoutis ◽  
Anna Papa ◽  
Danai Pervanidou ◽  
Chrysostomos I. Dovas

2010 ◽  
Vol 365 (1548) ◽  
pp. 1871-1878 ◽  
Author(s):  
Giusi Amore ◽  
Luigi Bertolotti ◽  
Gabriel L. Hamer ◽  
Uriel D. Kitron ◽  
Edward D. Walker ◽  
...  

West Nile virus has evolved in concert with its expansion across North America, but little is known about the evolutionary dynamics of the virus on local scales. We analysed viral nucleotide sequences from mosquitoes collected in 2005, 2006, and 2007 from a known transmission ‘hot spot’ in suburban Chicago, USA. Within this approximately 11 × 14 km area, the viral envelope gene has increased approximately 0.1% yr −1 in nucleotide-level genetic diversity. In each year, viral diversity was higher in ‘residential’ sites characterized by dense housing than in more open ‘urban green space’ sites such as cemeteries and parks. Phylodynamic analyses showed an increase in incidence around 2005, consistent with a higher-than-average peak in mosquito and human infection rates that year. Analyses of times to most recent common ancestor suggest that WNV in 2005 and 2006 may have arisen predominantly from viruses present during 2004 and 2005, respectively, but that WNV in 2007 had an older common ancestor, perhaps indicating a predominantly mixed or exogenous origin. These results show that the population of WNV in suburban Chicago is an admixture of viruses that are both locally derived and introduced from elsewhere, containing evolutionary information aggregated across a breadth of spatial and temporal scales.


Author(s):  
Ozge Erdogan Bamac ◽  
Utku Y. Cizmecigil ◽  
Asli Mete ◽  
Aysun Yilmaz ◽  
Ozge Aydin ◽  
...  
Keyword(s):  

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Ani Ioana Cotar ◽  
Elena Fălcuță ◽  
Sorin Dinu ◽  
Adriana Necula ◽  
Victoria Bîrluțiu ◽  
...  
Keyword(s):  

2009 ◽  
Vol 15 (6) ◽  
pp. 877-884 ◽  
Author(s):  
Marietjie Venter ◽  
Stacey Human ◽  
Dewald Zaayman ◽  
Gertruida H. Gerdes ◽  
June Williams ◽  
...  

2013 ◽  
Vol 141 (11) ◽  
pp. 2313-2316 ◽  
Author(s):  
G. SAVINI ◽  
G. PUGGIONI ◽  
A. DI GENNARO ◽  
G. DI FRANCESCO ◽  
A. M. ROCCHIGIANI ◽  
...  

SUMMARYWest Nile virus (WNV) strains belonging to lineage 2 were detected and isolated from the tissues of a goshawk and two carrion crows in Sardinia in August 2012. According to NS3 sequence analysis, the Sardinian isolates shared a high level of similarity with those of Italian lineage 2 strains which circulated in 2011 and with the homologous sequence of the 2004 Hungarian isolate. Following the human fatality reported in 2011 in Olbia, this study is the first to report the spread and enzootic circulation of WNV lineage 2 in Sardinia.


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