Correction to: West Nile virus in Europe: after action reviews of preparedness and response to the 2018 transmission season in Italy, Slovenia, Serbia and Greece

Abstract One of the main impacts of climate change on health is the influence on vector-borne diseases (VBDs). During the last few years, yearly outbreaks of the West Nile virus (WNV) have occurred in many locations, providing evidence of ongoing transmission. Currently, it is the most widely distributed arbovirus in the world. Increases in ambient temperature have impacts on WNV transmission. Indeed, clear associations were found between warm conditions and WNV outbreaks in various areas. The impact of changes in rainfall patterns on the incidence of the disease is influenced by the amount of precipitation (increased rainfall, floods or droughts), depending on the local conditions and the differences in the ecology and sensitivity of the species of mosquito. Predictions indicate that for WNV, increased warming will result in latitudinal and altitudinal expansions of regions climatically suitable for transmission, particularly along the current edges of its transmission areas. Extension of the transmission season is also predicted. As models show that the current climate change trends are expected to continue, it is important to reinforce WNV control efforts and increase the resilience of population health. For a better preparedness, any assessment of future transmission of WNV should consider the impacts of the changing climate.

Download Full-text

SURVEILLANCE RESULTS FROM THE FIRST WEST NILE VIRUS TRANSMISSION SEASON IN FLORIDA, 2001

American Journal of Tropical Medicine and Hygiene ◽

10.4269/ajtmh.2003.69.141 ◽

2003 ◽

Vol 69 (2) ◽

pp. 141-150 ◽

Cited By ~ 66

Author(s):

CARINA G. M. BLACKMORE ◽

ROBIN L. OLIVERI ◽

WILLIAM C. JETER ◽

LILLIAN M. STARK ◽

STEVEN T. WIERSMA ◽

...

Keyword(s):

West Nile Virus ◽

Virus Transmission ◽

West Nile ◽

Transmission Season ◽

West Nile Virus Transmission

Download Full-text

The abundance and diversity of West Nile virus mosquito vectors in two Regional Units of Greece during the onset of the 2018 transmission season

10.1101/735522 ◽

2019 ◽

Author(s):

Marina Bisia ◽

Claire L Jeffries ◽

Ioanna Lytra ◽

Antonios Michaelakis ◽

Thomas Walker

Keyword(s):

West Nile Virus ◽

Mosquito Species ◽

Early Period ◽

Entomological Surveillance ◽

West Nile ◽

Additional Species ◽

Transmission Season ◽

Molecular Barcoding ◽

Of Greece ◽

Molecular Xenomonitoring

AbstractBackgroundWest Nile virus (WNV) is a zoonotic arbovirus of great medical and veterinary importance, threatening the health of humans and equines worldwide. Mosquitoes belonging to the Culex (Cx.) pipiens complex are major vectors but numerous other mosquito species have also been implicated as vectors of WNV. Due to variations in blood-feeding behaviour, the different biotypes and hybrids of Cx. pipiens influence the transmission of WNV, from enzootic cycles (between mosquitoes and birds), to spill-over transmission to humans and equines.MethodsIn this study, mosquitoes were collected and analysed from two regional units (RUs) of Greece with reported cases of WNV within the past 4 years; Palaio Flairo and Argolida (in Attica and Peloponnese regions, respectively). Collections using different types of mosquito surveillance traps were undertaken in May-June 2018 during the early period of the WNV transmission season.ResultsA total of 1062 mosquitoes were collected, with Biogents Sentinel traps (BG traps) collecting both a greater number of mosquitoes across all species and Cx. pipiens complex individuals than Centres for Disease Control miniature light traps (CDC traps) or Heavy Duty Encephalitis Vector Survey traps (EVS traps). Identification of collected mosquitoes (using both morphological keys and molecular barcoding) confirmed the presence of additional species including Aedes (Ae.) albopictus, Ae. caspius and Culiseta (Cs.) longiareolata. The prevalence of Cx. pipiens biotypes in the RU of Palaio Faliro was 54.5% pipiens type, 20.0% molestus type and 25.5% hybrids. In the RU of Argolida, the collection comprised 68.1% pipiens type, 8.3% molestus type and 23.6% hybrids. Screening individual unfed female mosquitoes for WNV (molecular xenomonitoring) resulted in detection in three females of the pipiens type and in one hybrid; all collected from the RU of Argolida.ConclusionsAs hybrids play an important role in spill-over transmission of WNV to humans and equines, these findings highlight the importance of undertaking entomological surveillance programs incorporating molecular xenomonitoring at the onset of the transmission season to provide an early warning system for health authorities aiming to prevent WNV outbreaks in Greece.

Download Full-text

A Comparison of Adult Mosquito Trapping Methods to Assess Potential West Nile Virus Mosquito Vectors in Greece during the Onset of the 2018 Transmission Season

Insects ◽

10.3390/insects11060329 ◽

2020 ◽

Vol 11 (6) ◽

pp. 329

Author(s):

Marina Bisia ◽

Claire L. Jeffries ◽

Ioanna Lytra ◽

Antonios Michaelakis ◽

Thomas Walker

Keyword(s):

West Nile Virus ◽

Mosquito Species ◽

Early Period ◽

Blood Feeding ◽

Adult Mosquito ◽

Entomological Surveillance ◽

West Nile ◽

Additional Species ◽

Transmission Season ◽

Surveillance Programs

West Nile virus (WNV) threatens the health of humans and equines worldwide. Culex (Cx.) pipiens complex mosquitoes are major vectors but numerous other species have been implicated. Due to variations in blood-feeding behaviour, Cx. pipiens biotypes and hybrids influence transmission, from enzootic cycles (between mosquitoes and birds), to spill-over transmission to humans and equines. In this study, mosquitoes were collected in May–June 2018 during the early period of the transmission season from two regional units of Greece, where WNV cases had been reported in the previous four years (Palaio Faliro and Argolida). A total of 1062 mosquitoes were collected with Biogents Sentinel 2 traps collecting both a greater number of all mosquito species and the Cx. pipiens complex than CDC miniature light traps or Heavy Duty EVS traps. Molecular identification confirmed additional species including Aedes albopictus. The proportion of Cx. pipiens biotypes in Palaio Faliro was 54.5% pipiens, 20.0% molestus and 25.5% hybrids. In Argolida, the collection comprised 68.1% pipiens biotype, 8.3% molestus biotype and 23.6% hybrids. Screening resulted in WNV detection in three females of the pipiens biotype and in one hybrid. As hybrids play a role in spill-over transmission, these findings highlight the importance of entomological surveillance programs incorporating molecular xenomonitoring as an early warning before human cases at the onset of the transmission season.

Download Full-text

West Nile virus outbreak in humans and epidemiological surveillance, west Andalusia, Spain, 2016

Eurosurveillance ◽

10.2807/1560-7917.es.2018.23.14.17-00261 ◽

2018 ◽

Vol 23 (14) ◽

Cited By ~ 9

Author(s):

Nuria López-Ruiz ◽

María del Carmen Montaño-Remacha ◽

Enric Durán-Pla ◽

Mercedes Pérez-Ruiz ◽

Jose María Navarro-Marí ◽

...

Keyword(s):

West Nile Virus ◽

Wild Birds ◽

Epidemiological Surveillance ◽

Southern Europe ◽

West Nile ◽

Transmission Season ◽

Epidemiological Changes ◽

First Time ◽

Regional Surveillance

In Andalusia, Spain, West Nile virus (WNV) surveillance takes place from April to November, during the active vector period. Within this area seroconversion to this virus was evidenced in wild birds in 2004, affecting horses and two humans for the first time in 2010. Since 2010, the virus has been isolated every year in horses, and national and regional surveillance plans have been updated with the epidemiological changes found. WNV is spreading rapidly throughout southern Europe and has caused outbreaks in humans. Here we describe the second WNV outbreak in humans in Andalusia, with three confirmed cases, which occurred between August and September 2016, and the measures carried out to control it. Surveillance during the transmission season is essential to monitor and ensure prompt identification of any outbreaks.

Download Full-text

Extraordinary increase in West Nile virus cases and first confirmed human Usutu virus infection in Hungary, 2018

Eurosurveillance ◽

10.2807/1560-7917.es.2019.24.28.1900038 ◽

2019 ◽

Vol 24 (28) ◽

Cited By ~ 23

Author(s):

Anna Nagy ◽

Eszter Mezei ◽

Orsolya Nagy ◽

Tamás Bakonyi ◽

Nikolett Csonka ◽

...

Keyword(s):

West Nile Virus ◽

Nucleic Acid ◽

Whole Blood ◽

Urine Samples ◽

Differential Diagnostics ◽

Sample Type ◽

West Nile ◽

Viral Nucleic Acid ◽

Transmission Season ◽

Usutu Virus

Background During the 2018 WNV transmission season, similarly to other endemic areas in Europe, a large number of human West Nile virus (WNV) infections were reported in Hungary. Aims We summarise the epidemiological and laboratory findings of the 2018 transmission season and expand experiences in flavivirus differential diagnostics. Methods Every patient with clinical suspicion of acute WNV infection was in parallel tested for WNV, tick-borne encephalitis virus and Usutu virus (USUV) by serological methods. Sera, whole blood and urine samples were also tested for the presence of viral nucleic acid. Results Until the end of December 2018, 215 locally acquired and 10 imported human WNV infections were notified in Hungary. All reported cases were symptomatic; most of them exhibited neurological symptoms. In a large proportion of tested individuals, whole blood was the most appropriate sample type for viral nucleic acid detection, but because whole blood samples were not always available, testing of urine samples also extended diagnostic possibilities. In addition, the first human USUV infection was confirmed in 2018 in a patient with aseptic meningitis. Serological cross-reactions with WNV in different serological assays were experienced, but subsequent molecular biological testing and sequence analysis identified Europe lineage 2 USUV infection. Conclusion Careful interpretation and simultaneous application of different laboratory methods are necessary to avoid misdiagnosis of human USUV cases. Expansion of the laboratory-confirmed case definition criteria for detection of viral RNA in any clinical specimens to include urine samples could increase diagnostic sensitivity.

Download Full-text

West Nile virus circulation in south-eastern Romania, 2011 to 2013

Eurosurveillance ◽

10.2807/1560-7917.es2015.20.20.21130 ◽

2015 ◽

Vol 20 (20) ◽

Cited By ~ 18

Author(s):

S Dinu ◽

A I Cotar ◽

I R Pănculescu-Gătej ◽

E Fălcuţă ◽

F L Prioteasa ◽

...

Keyword(s):

West Nile Virus ◽

Sub Saharan Africa ◽

Molecular Evidence ◽

West Nile Fever ◽

West Nile ◽

Transmission Season ◽

South Eastern ◽

Human Sera ◽

Lineage 2 ◽

Sub Saharan

Lineage 2 West Nile virus (WNV), previously found only in sub-Saharan Africa and Madagascar, was identified in Hungary in 2004 and has rapidly expanded in Europe in the past decade. Following a significant outbreak of West Nile fever with neurological cases caused by lineage 1 WNV in Romania in 1996, scattered cases have been recorded in the south-east of the country in each transmission season. Another outbreak, affecting a larger area and caused by lineage 2 WNV, was recorded in 2010. We analysed human sera from neuroinvasive West Nile fever cases and mosquitoes, sampled in south-eastern Romania between 2011 and 2013, for the presence of WNV genome, and obtained partial NS5 and envelope glycoprotein sequences. Human- and mosquito-derived WNV sequences were highly similar (99%) to Volgograd 2007 lineage 2 WNV and differed from isolates previously detected in central and southern Europe. WNV was detected in one pool of Culex pipiens s.l. males, documenting vertical transmission. Lineage 4 WNV, of unknown pathogenicity to mammals, was found in the amphibian-feeding mosquito Uranotaenia unguiculata from the Danube Delta. Our results present molecular evidence for the maintenance of the same isolates of Volgograd 2007-like lineage 2 WNV in south-eastern Romania between 2011 and 2013.

Download Full-text