Co‐Infections: Simultaneous Detections of West Nile Virus and Usutu Virus in Birds from Germany

In the period from 2015 to 2020, an entomological survey for the presence of West Nile virus (WNV) and Usutu virus (USUV) in mosquitoes was performed in northwestern Croatia. A total of 20,363 mosquitoes were sampled in the City of Zagreb and Međimurje county, grouped in 899 pools and tested by real-time RT-PCR for WNV and USUV RNA. All pools were negative for WNV while one pool each from 2016 (Aedes albopictus), 2017 (Culex pipiens complex), 2018 (Cx. pipiens complex), and 2019 (Cx. pipiens complex), respectively, was positive for USUV. The 2018 and 2019 positive pools shared 99.31% nucleotide homology within the USUV NS5 gene and both clustered within USUV Europe 2 lineage. The next-generation sequencing of one mosquito pool (Cx. pipiens complex) collected in 2018 in Zagreb confirmed the presence of USUV and revealed several dsDNA and ssRNA viruses of insect, bacterial and mammalian origin.

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Surveillance on antibodies against West Nile virus, Usutu virus, tick-borne encephalitis virus and Tribeč virus in wild birds in Drienovská wetland, Slovakia

Biologia ◽

10.2478/s11756-019-00211-4 ◽

2019 ◽

Vol 74 (7) ◽

pp. 813-820 ◽

Cited By ~ 3

Author(s):

Tomáš Csank ◽

Ľuboš Korytár ◽

Terézia Pošiváková ◽

Tamás Bakonyi ◽

Juraj Pistl ◽

...

Keyword(s):

West Nile Virus ◽

Wild Birds ◽

Encephalitis Virus ◽

West Nile ◽

Usutu Virus ◽

Tick Borne Encephalitis ◽

Tick Borne Encephalitis Virus

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Increase in human West Nile and Usutu virus infections, Austria, 2018

Eurosurveillance ◽

10.2807/1560-7917.es.2018.23.43.1800545 ◽

2018 ◽

Vol 23 (43) ◽

Cited By ~ 40

Author(s):

Stephan W. Aberle ◽

Jolanta Kolodziejek ◽

Christof Jungbauer ◽

Karin Stiasny ◽

Judith H. Aberle ◽

...

Keyword(s):

West Nile Virus ◽

Blood Donors ◽

Blood Donation ◽

Virus Infections ◽

West Nile Fever ◽

West Nile ◽

Usutu Virus ◽

Neuroinvasive Disease ◽

Human West Nile Virus ◽

Imported Cases

Between 28 June and 17 September 2018, 27 cases of human West Nile virus infections were recorded in Austria; four cases of West Nile neuroinvasive disease, 11 cases of West Nile fever, six infections detected by blood donation screening and six imported cases. In addition, 18 cases of human Usutu virus infections (all blood donors) were recorded. This is the highest number of annual infections recorded in Austria since the introduction of both viruses.

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Co-Circulation of West Nile and Usutu Flaviviruses in Mosquitoes in Slovakia, 2018

Viruses ◽

10.3390/v11070639 ◽

2019 ◽

Vol 11 (7) ◽

pp. 639 ◽

Cited By ~ 9

Author(s):

Viktória Čabanová ◽

Silvie Šikutová ◽

Petra Straková ◽

Oldřich Šebesta ◽

Bronislava Vichová ◽

...

Keyword(s):

European Union ◽

West Nile Virus ◽

The European Union ◽

West Nile ◽

Usutu Virus ◽

Pathogenic Viruses ◽

Lineage 2 ◽

First Time

Monitoring West Nile virus (WNV) and Usutu virus (USUV) activity now has the highest priority among mosquito-borne pathogenic viruses circulating in the European Union. This study documents a first time detection and the co-circulation of WNV lineage-2 (with the minimal prevalence of 0.46%) and USUV clade Europe 2 (with the minimal prevalence of 0.25%) in mosquitoes from the same habitat of south-western Slovakia and underlines necessity to perform rigorous surveillance in birds, mosquitoes, horses and humans in that country.

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Detection of Usutu Virus Within a West Nile Virus Surveillance Program in Northern Italy

Vector-Borne and Zoonotic Diseases ◽

10.1089/vbz.2010.0055 ◽

2011 ◽

Vol 11 (5) ◽

pp. 551-557 ◽

Cited By ~ 45

Author(s):

Marco Tamba ◽

Paolo Bonilauri ◽

Romeo Bellini ◽

Mattia Calzolari ◽

Alessandro Albieri ◽

...

Keyword(s):

West Nile Virus ◽

Northern Italy ◽

Surveillance Program ◽

West Nile ◽

Usutu Virus ◽

Virus Surveillance

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Protection of a Single Dose West Nile Virus Recombinant Subviral Particle Vaccine against Lineage 1 or 2 Strains and Analysis of the Cross-Reactivity with Usutu Virus

PLoS ONE ◽

10.1371/journal.pone.0108056 ◽

2014 ◽

Vol 9 (9) ◽

pp. e108056 ◽

Cited By ~ 22

Author(s):

Teresa Merino-Ramos ◽

Ana-Belén Blázquez ◽

Estela Escribano-Romero ◽

Rodrigo Cañas-Arranz ◽

Francisco Sobrino ◽

...

Keyword(s):

Single Dose ◽

West Nile Virus ◽

Cross Reactivity ◽

West Nile ◽

Usutu Virus ◽

Virus Recombinant ◽

The Cross ◽

Subviral Particle

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Co-circulation of Usutu virus and West Nile virus in a reed bed ecosystem

Parasites & Vectors ◽

10.1186/s13071-015-1139-0 ◽

2015 ◽

Vol 8 (1) ◽

Cited By ~ 21

Author(s):

Ivo Rudolf ◽

Tamás Bakonyi ◽

Oldřich Šebesta ◽

Jan Mendel ◽

Juraj Peško ◽

...

Keyword(s):

West Nile Virus ◽

West Nile ◽

Usutu Virus ◽

Reed Bed

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Seasonal Phenological Patterns and Flavivirus Vectorial Capacity of Medically Important Mosquito Species in a Wetland and an Urban Area of Attica, Greece

Tropical Medicine and Infectious Disease ◽

10.3390/tropicalmed6040176 ◽

2021 ◽

Vol 6 (4) ◽

pp. 176

Author(s):

Stavroula Beleri ◽

Georgios Balatsos ◽

Vasilios Karras ◽

Nikolaos Tegos ◽

Fani Sereti ◽

...

Keyword(s):

Public Health ◽

West Nile Virus ◽

Mosquito Species ◽

Vectorial Capacity ◽

Adult Mosquito ◽

Surveillance Program ◽

The South ◽

Public Health Importance ◽

West Nile ◽

Usutu Virus

Seasonal patterns of mosquito population density and their vectorial capacity constitute major elements to understand the epidemiology of mosquito-borne diseases. Using adult mosquito traps, we compared the population dynamics of major mosquito species (Culex pipiens, Aedes albopictus, Anopheles spp.) in an urban and a wetland rural area of Attica Greece. Pools of the captured Cx. pipiens were analyzed to determine infection rates of the West Nile virus (WNV) and the Usutu virus (USUV). The data provided were collected under the frame of the surveillance program carried out in two regional units (RUs) of the Attica region (East Attica and South Sector of Attica), during the period 2017–2018. The entomological surveillance of adult mosquitoes was performed on a weekly basis using a network of BG-sentinel traps (BGs), baited with CO2 and BG-Lure, in selected, fixed sampling sites. A total of 46,726 adult mosquitoes were collected, with larger variety and number of species in East Attica (n = 37,810), followed by the South Sector of Attica (n = 8916). The collected mosquitoes were morphologically identified to species level and evaluated for their public health importance. Collected Cx. pipiens adults were pooled and tested for West Nile virus (WNV) and Usutu virus (USUV) presence by implementation of a targeted molecular methodology (real-time PCR). A total of 366 mosquito pools were analyzed for WNV and USUV, respectively, and 38 (10.4%) positive samples were recorded for WNV, while no positive pool was detected for USUV. The majority of positive samples for WNV were detected in the East Attica region, followed by the South Sector of Attica, respectively. The findings of the current study highlight the WNV circulation in the region of Attica and the concomitant risk for the country, rendering mosquito surveillance actions and integrated mosquito management programs as imperative public health interventions.

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Usutu virus uses langerin as a receptor to productively infect Langerhans cells more efficiently than West Nile virus

10.1101/2021.08.17.456611 ◽

2021 ◽

Author(s):

Marie-France Martin ◽

Ghizlane Maarifi ◽

Hervé Abiven ◽

Marine Seffals ◽

Nicolas Mouchet ◽

...

Keyword(s):

Immune Response ◽

West Nile Virus ◽

Human Skin ◽

Langerhans Cells ◽

Ectopic Expression ◽

Target Cells ◽

Global Public Health ◽

West Nile ◽

Lectin Receptors ◽

Usutu Virus

AbstractUsutu virus (USUV) and West Nile virus (WNV) are emerging flaviviruses transmitted by mosquitoes. Although they differ in their endemicity, with WNV present throughout much of the world and USUV currently limited to Africa and Europe, both constitute a global public health threat. Since they are directly inoculated in the epidermis and the dermis during mosquito bites, the skin constitutes the initial site of viral replication and immune response. The skin is equipped with a unique network of dendritic cells, which represent an essential outpost of immune defenses. These skin-resident DCs comprise Langerhans cells (LCs) in the epidermis and dermal DCs in the dermis, which capture pathogens through the C-type lectin receptors (CLR) langerin and DC-SIGN, respectively. Despite the key role of these cells in the body’s antiviral defenses, their implication in the immune control and replication of WNV and USUV is not known.Using human skin explants, we show that while both viruses can replicate in keratinocytes, they can also infect resident DCs with distinct tropism, since WNV preferentially infects DCs in the dermis, whereas USUV has a greater propensity to infect LCs. Using both purified human epidermal LCs (eLCs) and monocyte derived LCs (MoLCs), we confirm that LCs sustain a faster and more efficient replication of USUV compared with WNV and that this correlates with a more intense innate immune response to USUV compared with WNV.Next, we show that ectopic expression of langerin in non-permissive cells rendered them permissive to USUV, but not to WNV. Conversely, blocking or silencing langerin in MoLCs or eLCs made them resistant to USUV infection, thus demonstrating that this specific CLR allows USUV to enter and productively infect LCs.Altogether, our results demonstrate that LCs constitute privileged target cells for USUV in human skin, because langerin favors its entry and replication. Intriguingly, this suggests that USUV efficiently escapes the antiviral functions of langerin, which normally safeguards LCs from most viral infections.

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Establishment of Culex modestus in Belgium and a Glance into the Virome of Belgian Mosquito Species

mSphere ◽

10.1128/msphere.01229-20 ◽

2021 ◽

Vol 6 (2) ◽

Author(s):

Lanjiao Wang ◽

Ana Lucia Rosales Rosas ◽

Lander De Coninck ◽

Chenyan Shi ◽

Johanna Bouckaert ◽

...

Keyword(s):

West Nile Virus ◽

Mosquito Species ◽

Large Population ◽

Coi Gene ◽

West Nile ◽

Content Type ◽

Usutu Virus ◽

Surveillance Programs ◽

Surrounding Areas ◽

The City

ABSTRACT Culex modestus mosquitoes are considered potential transmission vectors of West Nile virus and Usutu virus. Their presence has been reported across several European countries, including one larva detected in Belgium in 2018. In this study, mosquitoes were collected in the city of Leuven and surrounding areas in the summers of 2019 and 2020. Species identification was performed based on morphological features and partial sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene. The 107 mosquitoes collected in 2019 belonged to eight mosquito species, Culex pipiens (24.3%), Cx. modestus (48.6%), Cx. torrentium (0.9%), Culiseta annulata (0.9%), Culiseta morsitans (0.9%), Aedes sticticus (14.0%), Aedes cinereus (9.3%), and Anopheles plumbeus (0.9%), suggesting the presence of an established Cx. modestus population in Belgium. The collection of Cx. modestus mosquitoes at the same locations in 2020 confirmed their establishment in the region. Haplotype network analysis of the COI sequences for Cx. modestus showed that the Belgian population is rather diverse, suggesting that it may have been established in Belgium for some time. The Belgian Cx. modestus population was most closely related to populations from the United Kingdom and Germany. Characterization of the virome of the collected mosquitoes resulted in the identification of at least 33 eukaryotic viral species. Nine (nearly) complete genomes belonging to 6 viral species were identified, all of which were closely related to known viruses. In conclusion, here, we report the presence of Cx. modestus in the surrounding areas of Leuven, Belgium. As this species is considered to be a vector of several arboviruses, the implementation of vector surveillance programs to monitor this species is recommended. IMPORTANCE Culex modestus mosquitoes are considered to be a potential “bridge” vector, being able to transmit pathogens between birds as well as from birds to mammals, including humans. In Belgium, this mosquito species was considered absent until the finding of one larva in 2018 and subsequent evidence of a large population in 2019 to 2020 described here. We collected mosquitoes in the summers of 2019 and 2020 in the city of Leuven and surrounding areas. The mosquito species was identified by morphological and molecular methods, demonstrating the presence of Cx. modestus in this region. The ability of mosquitoes to transmit pathogens can depend on several factors, one of them being their natural virus composition. Therefore, we identified the mosquito-specific viruses harbored by Belgian mosquitoes. As Cx. modestus is able to transmit viruses such as West Nile virus and Usutu virus, the establishment of this mosquito species may increase the risk of virus transmission in the region. It is thus advisable to implement mosquito surveillance programs to monitor this species.

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