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

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.

scholarly journals 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 ◽  
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.

scholarly journals Population dynamics of mosquito species in a West Nile virus endemic area in Madagascar

Parasite ◽  
2017 ◽  
Vol 24 ◽  
pp. 3 ◽  
Author(s):  
Luciano Michaël Tantely ◽  
Catherine Cêtre-Sossah ◽  
Tsiriniaina Rakotondranaivo ◽  
Eric Cardinale ◽  
Sébastien Boyer
Keyword(s):  
Population Dynamics ◽  
West Nile Virus ◽  
Endemic Area ◽  
Mosquito Species ◽  
West Nile

scholarly journals Epidemiology of West Nile virus in Africa: An underestimated threat

2022 ◽  
Vol 16 (1) ◽  
pp. e0010075
Author(s):  
Giulia Mencattelli ◽  
Marie Henriette Dior Ndione ◽  
Roberto Rosà ◽  
Giovanni Marini ◽  
Cheikh Tidiane Diagne ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Disease Burden ◽  
Vector Competence ◽  
Mosquito Species ◽  
Global Scale ◽  
Reference List ◽  
African Continent ◽  
West Nile ◽  
Scientific Papers ◽  
Epidemiological Pattern

Background West Nile virus is a mosquito-borne flavivirus which has been posing continuous challenges to public health worldwide due to the identification of new lineages and clades and its ability to invade and establish in an increasing number of countries. Its current distribution, genetic variability, ecology, and epidemiological pattern in the African continent are only partially known despite the general consensus on the urgency to obtain such information for quantifying the actual disease burden in Africa other than to predict future threats at global scale. Methodology and principal findings References were searched in PubMed and Google Scholar electronic databases on January 21, 2020, using selected keywords, without language and date restriction. Additional manual searches of reference list were carried out. Further references have been later added accordingly to experts’ opinion. We included 153 scientific papers published between 1940 and 2021. This review highlights: (i) the co-circulation of WNV-lineages 1, 2, and 8 in the African continent; (ii) the presence of diverse WNV competent vectors in Africa, mainly belonging to the Culex genus; (iii) the lack of vector competence studies for several other mosquito species found naturally infected with WNV in Africa; (iv) the need of more competence studies to be addressed on ticks; (iv) evidence of circulation of WNV among humans, animals and vectors in at least 28 Countries; (v) the lack of knowledge on the epidemiological situation of WNV for 19 Countries and (vii) the importance of carrying out specific serological surveys in order to avoid possible bias on WNV circulation in Africa. Conclusions This study provides the state of art on WNV investigation carried out in Africa, highlighting several knowledge gaps regarding i) the current WNV distribution and genetic diversity, ii) its ecology and transmission chains including the role of different arthropods and vertebrate species as competent reservoirs, and iii) the real disease burden for humans and animals. This review highlights the needs for further research and coordinated surveillance efforts on WNV in Africa.

scholarly journals Serological, Molecular and Entomological Surveillance Demonstrates Widespread Circulation of West Nile Virus in Turkey

2014 ◽  
Vol 8 (7) ◽  
pp. e3028 ◽  
Author(s):  
Koray Ergunay ◽  
Filiz Gunay ◽  
Ozge Erisoz Kasap ◽  
Kerem Oter ◽  
Sepandar Gargari ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Entomological Surveillance ◽  
West Nile

scholarly journals Pre-existing Microfilarial Infections of American Robins (Passeriformes: Turdidae) and Common Grackles (Passeriformes: Icteridae) Have Limited Impact on Enhancing Dissemination of West Nile Virus in Culex pipiens Mosquitoes (Diptera: Culicidae)

2020 ◽  
Author(s):  
Jefferson A Vaughan ◽  
Juanita Hinson ◽  
Elizabeth S Andrews ◽  
Michael J Turell
Keyword(s):  
West Nile Virus ◽  
Viral Infection ◽  
Culex Pipiens ◽  
Mosquito Species ◽  
Immature Stages ◽  
West Nile ◽  
Limited Impact ◽  
Nematode Parasites ◽  
American Robins ◽  
Specific Virus

Abstract Microfilariae (MF) are the immature stages of filarial nematode parasites and inhabit the blood and dermis of all classes of vertebrates, except fish. Concurrent ingestion of MF and arboviruses by mosquitoes can enhance mosquito transmission of virus compared to when virus is ingested alone. Shortly after being ingested, MF penetrate the mosquito’s midgut and may introduce virus into the mosquito’s hemocoel, creating a disseminated viral infection much sooner than normal. This phenomenon is known as microfilarial enhancement. Both American Robins and Common Grackles harbor MF—that is, Eufilaria sp. and Chandlerella quiscali von Linstow (Spirurida: Onchocercidae), respectively. We compared infection and dissemination rates in Culex pipiens L. mosquitoes that fed on birds with and without MF infections that had been infected with West Nile virus (WNV). At moderate viremias, about 107 plaque-forming units (pfu)/ml of blood, there were no differences in infection or dissemination rates among mosquitoes that ingested viremic blood from a bird with or without microfilaremia. At high viremias, >108.5 pfu/ml, mosquitoes feeding on a microfilaremic Grackle with concurrent viremia had significantly higher infection and dissemination rates than mosquitoes fed on viremic Grackles without microfilaremia. Microfilarial enhancement depends on the specific virus, MF, and mosquito species examined. How virus is introduced into the hemocoel by MF differs between the avian/WNV systems described here (i.e., leakage) and various arboviruses with MF of the human filarid, Brugia malayi (Brug) (Spirurida: Onchocercidae) (i.e., cotransport). Additional studies are needed to determine if other avian species and their MF are involved in the microfilarial enhancement of WNV in nature.

Effects of climate change on vector-borne diseases: an updated focus on West Nile virus in humans

2019 ◽  
Vol 3 (2) ◽  
pp. 143-152 ◽  
Author(s):  
Shlomit Paz
Keyword(s):  
Climate Change ◽  
West Nile Virus ◽  
The West ◽  
West Nile ◽  
Local Conditions ◽  
Transmission Season ◽  
Vector Borne Diseases ◽  
Vector Borne ◽  
The Impact ◽  
Impacts Of Climate Change

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.

scholarly journals 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

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Flavia Riccardo ◽  
Francesco Bolici ◽  
Mario Fafangel ◽  
Verica Jovanovic ◽  
Maja Socan ◽  
...  
Keyword(s):  
West Nile Virus ◽  
West Nile ◽  
Transmission Season ◽  
After Action Reviews

Retrospective space–time analysis methods to support West Nile virus surveillance activities

2014 ◽  
Vol 143 (1) ◽  
pp. 202-213 ◽  
Author(s):  
P. MULATTI ◽  
M. MAZZUCATO ◽  
F. MONTARSI ◽  
S. CIOCCHETTA ◽  
G. CAPELLI ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Linear Models ◽  
Space Time ◽  
Scan Statistics ◽  
Limited Area ◽  
Entomological Surveillance ◽  
West Nile ◽  
Spatial And Temporal Scales ◽  
Virus Surveillance ◽  
Human West Nile Virus

SUMMARYThe steep increase in human West Nile virus (WNV) infections in 2011–2012 in north-eastern Italy prompted a refinement of the surveillance plan. Data from the 2010–2012 surveillance activities on mosquitoes, equines, and humans were analysed through Bernoulli space–time scan statistics, to detect the presence of recurrent WNV infection hotspots. Linear models were fit to detect the possible relationships between WNV occurrence in humans and its activity in mosquitoes. Clusters were detected for all of the hosts, defining a limited area on which to focus surveillance and promptly identify WNV reactivation. Positive relationships were identified between WNV in humans and in mosquitoes; although it was not possible to define precise spatial and temporal scales at which entomological surveillance could predict the increasing risk of human infections. This stresses the necessity to improve entomological surveillance by increasing both the density of trapping sites and the frequency of captures.

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

2003 ◽  
Vol 69 (2) ◽  
pp. 141-150 ◽  
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

Vector Competence of Australian Mosquito Species for a North American Strain of West Nile Virus

2008 ◽  
Vol 8 (6) ◽  
pp. 805-812 ◽  
Author(s):  
Cassie C. Jansen ◽  
Cameron E. Webb ◽  
Judith A. Northill ◽  
Scott A. Ritchie ◽  
Richard C. Russell ◽  
...  
Keyword(s):  
West Nile Virus ◽  
North American ◽  
Vector Competence ◽  
Mosquito Species ◽  
West Nile ◽  
North American Strain ◽  
American Strain
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