Whole genome sequencing and phylogenetic analysis of West Nile virus lineage 1 and lineage 2 from human cases of infection, Italy, August 2013

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.

Download Full-text

Contrasted Epidemiological Patterns of West Nile Virus Lineages 1 and 2 Infections in France from 2015 to 2019

Pathogens ◽

10.3390/pathogens9110908 ◽

2020 ◽

Vol 9 (11) ◽

pp. 908 ◽

Cited By ~ 1

Author(s):

Cécile Beck ◽

Isabelle Leparc Goffart ◽

Florian Franke ◽

Gaelle Gonzalez ◽

Marine Dumarest ◽

...

Keyword(s):

Spatial Distribution ◽

West Nile Virus ◽

Invasive Disease ◽

Northern Italy ◽

Breaking Point ◽

Organ Donors ◽

West Nile ◽

Organ Donations ◽

History Of ◽

Lineage 2

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.

Download Full-text

Human West Nile Virus Lineage 2 Infection: Epidemiological, Clinical, and Virological Findings

Viruses ◽

10.3390/v12040458 ◽

2020 ◽

Vol 12 (4) ◽

pp. 458 ◽

Cited By ~ 1

Author(s):

Monia Pacenti ◽

Alessandro Sinigaglia ◽

Elisa Franchin ◽

Silvana Pagni ◽

Enrico Lavezzo ◽

...

Keyword(s):

West Nile Virus ◽

Blood Donors ◽

Case Fatality ◽

West Nile ◽

Neuroinvasive Disease ◽

Human West Nile Virus ◽

Large Outbreak ◽

Study Population ◽

Lineage 2

West Nile virus (WNV) lineage 2 is expanding and causing large outbreaks in Europe. In this study, we analyzed the epidemiological, clinical, and virological features of WNV lineage 2 infection during the large outbreak that occurred in northern Italy in 2018. The study population included 86 patients with neuroinvasive disease (WNND), 307 with fever (WNF), and 34 blood donors. Phylogenetic analysis of WNV full genome sequences from patients’ samples showed that the virus belonged to the widespread central/southern European clade of WNV lineage 2 and was circulating in the area at least since 2014. The incidence of WNND and WNF progressively increased with age and was higher in males than in females. Among WNND patients, the case fatality rate was 22%. About 70% of blood donors reported symptoms during follow-up. Within the first week after symptom onset, WNV RNA was detectable in the blood or urine of 80% of patients, while 20% and 40% of WNND and WNF patients, respectively, were WNV IgM-seronegative. In CSF samples of WNND patients, WNV RNA was typically detectable when WNV IgM antibodies were absent. Blunted or no WNV IgM response and high WNV IgG levels were observed in seven patients with previous flavivirus immunity.

Download Full-text

Evidence of West Nile virus lineage 2 circulation in Northern Italy

Veterinary Microbiology ◽

10.1016/j.vetmic.2012.02.018 ◽

2012 ◽

Vol 158 (3-4) ◽

pp. 267-273 ◽

Cited By ~ 68

Author(s):

G. Savini ◽

G. Capelli ◽

F. Monaco ◽

A. Polci ◽

F. Russo ◽

...

Keyword(s):

West Nile Virus ◽

Northern Italy ◽

West Nile ◽

Lineage 2

Download Full-text

Novel West Nile virus lineage 1a full genome sequences from human cases of infection in north-eastern Italy, 2011

Clinical Microbiology and Infection ◽

10.1111/1469-0691.12001 ◽

2012 ◽

Vol 18 (12) ◽

pp. E541-E544 ◽

Cited By ~ 18

Author(s):

L. Barzon ◽

M. Pacenti ◽

E. Franchin ◽

L. Squarzon ◽

E. Lavezzo ◽

...

Keyword(s):

West Nile Virus ◽

Full Genome ◽

Genome Sequences ◽

West Nile ◽

North Eastern

Download Full-text

Simultaneous circulation of two West Nile virus lineage 2 clades and Bagaza virus in the Zambezi region, Namibia

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0009311 ◽

2021 ◽

Vol 15 (4) ◽

pp. e0009311

Author(s):

Heiko D. Guggemos ◽

Matthias Fendt ◽

Christian Hieke ◽

Verena Heyde ◽

John K. E. Mfune ◽

...

Keyword(s):

West Nile Virus ◽

National Parks ◽

Southern Africa ◽

Severe Disease ◽

West Nile ◽

Potential Health ◽

Economic Implications ◽

High Infection ◽

North Eastern ◽

Lineage 2

Flaviviruses include a great diversity of mosquito-borne arboviruses with epidemic potential and high global disease burden. Several flaviviruses are circulating in southern Africa affecting humans and livestock, among them West Nile virus (WNV) and Wesselsbron virus. Despite their high relevance, no arbovirus surveillance study has been conducted for more than 35 years in Namibia. In this study we assessed the diversity of flaviviruses circulating in mosquitoes in the densely populated, semi-tropical Zambezi region of north-eastern Namibia. In total, 10,206 mosquitoes were sampled in Bwabwata and Mudumu national parks and Mashi and Wuparo conservancies and screened for flavivirus infections. A high infection rate with insect-specific flaviviruses was found with 241 strains of two previously known and seven putative novel insect-specific flaviviruses. In addition, we identified ten strains of WNV in the main vector Cx. univittatus sampled in the Mashi conservancy. Surprisingly, the strains fell into two different clades of lineage 2, 2b and 2d. Further, three strains of Bagaza Virus (BAGV) were found in Cx. univittatus mosquitoes originating from Mudumu national park. Assessment of BAGV growth in different cell lines showed high replication rates in mosquito and duck cells and about 100,000fold lower replication in human, primate and rodent cells. We demonstrate a wide genetic diversity of flaviviruses is circulating in mosquitoes in the Zambezi region. Importantly, WNV and BAGV can cause outbreaks including severe disease and mortality in humans and birds, respectively. Future studies should focus on WNV and BAGV geographic distribution, as well as on their potential health impacts in and the associated social and economic implications for southern Africa.

Download Full-text