Pathogens

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3 pages, 183 KiB

Open AccessEditorial

West Nile Virus Infection

by Francisco Llorente

Pathogens 2023, 12(2), 151; https://doi.org/10.3390/pathogens12020151 - 17 Jan 2023

Cited by 1 | Viewed by 1593

Abstract

West Nile virus (WNV) is a mosquito-borne pathogen that belongs to the Flavivirus genus (family Flaviviridae) [...] Full article

(This article belongs to the Special Issue West Nile Virus Infection)

Research

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14 pages, 2325 KiB

Open AccessArticle

West Nile Virus in Brazil

by Érica Azevedo Costa, Marta Giovanetti, Lilian Silva Catenacci, Vagner Fonseca, Flávia Figueira Aburjaile, Flávia L. L. Chalhoub, Joilson Xavier, Felipe Campos de Melo Iani, Marcelo Adriano da Cunha e Silva Vieira, Danielle Freitas Henriques, Daniele Barbosa de Almeida Medeiros, Maria Isabel Maldonado Coelho Guedes, Beatriz Senra Álvares da Silva Santos, Aila Solimar Gonçalves Silva, Renata de Pino Albuquerque Maranhão, Nieli Rodrigues da Costa Faria, Renata Farinelli de Siqueira, Tulio de Oliveira, Karina Ribeiro Leite Jardim Cavalcante, Noely Fabiana Oliveira de Moura, Alessandro Pecego Martins Romano, Carlos F. Campelo de Albuquerque, Lauro César Soares Feitosa, José Joffre Martins Bayeux, Raffaella Bertoni Cavalcanti Teixeira, Osmaikon Lisboa Lobato, Silvokleio da Costa Silva, Ana Maria Bispo de Filippis, Rivaldo Venâncio da Cunha, José Lourenço and Luiz Carlos Junior Alcantara Show full author list Hide full author list

Pathogens 2021, 10(7), 896; https://doi.org/10.3390/pathogens10070896 - 15 Jul 2021

Cited by 14 | Viewed by 6073

Abstract

Background: West Nile virus (WNV) was first sequenced in Brazil in 2019, when it was isolated from a horse in the Espírito Santo state. Despite multiple studies reporting serological evidence suggestive of past circulation since 2004, WNV remains a low priority for surveillance [...] Read more.

Background: West Nile virus (WNV) was first sequenced in Brazil in 2019, when it was isolated from a horse in the Espírito Santo state. Despite multiple studies reporting serological evidence suggestive of past circulation since 2004, WNV remains a low priority for surveillance and public health, such that much is still unknown about its genomic diversity, evolution, and transmission in the country. Methods: A combination of diagnostic assays, nanopore sequencing, phylogenetic inference, and epidemiological modeling are here used to provide a holistic overview of what is known about WNV in Brazil. Results: We report new genetic evidence of WNV circulation in southern (Minas Gerais, São Paulo) and northeastern (Piauí) states isolated from equine red blood cells. A novel, climate-informed theoretical perspective of the potential transmission of WNV across the country highlights the state of Piauí as particularly relevant for WNV epidemiology in Brazil, although it does not reject possible circulation in other states. Conclusion: Our output demonstrates the scarceness of existing data, and that although there is sufficient evidence for the circulation and persistence of the virus, much is still unknown on its local evolution, epidemiology, and activity. We advocate for a shift to active surveillance, to ensure adequate preparedness for future epidemics with spill-over potential to humans. Full article

(This article belongs to the Special Issue West Nile Virus Infection)

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10 pages, 2817 KiB

Open AccessArticle

West Nile Virus Seroprevalence in the Italian Tuscany Region from 2016 to 2019

by Serena Marchi, Emanuele Montomoli, Simonetta Viviani, Simone Giannecchini, Maria A. Stincarelli, Gianvito Lanave, Michele Camero, Caterina Alessio, Rosa Coluccio and Claudia Maria Trombetta

Pathogens 2021, 10(7), 844; https://doi.org/10.3390/pathogens10070844 - 5 Jul 2021

Cited by 2 | Viewed by 2352

Abstract

Although in humans West Nile virus is mainly the cause of mild or sub-clinical infections, in some cases a neuroinvasive disease may occur predominantly in the elderly. In Italy, several cases of West Nile virus infection are reported every year. Tuscany was the [...] Read more.

Although in humans West Nile virus is mainly the cause of mild or sub-clinical infections, in some cases a neuroinvasive disease may occur predominantly in the elderly. In Italy, several cases of West Nile virus infection are reported every year. Tuscany was the first Italian region where the virus was identified; however, to date only two cases of infection have been reported in humans. This study aimed at evaluating the prevalence of antibodies against West Nile virus in the area of Siena Province to estimate the recent circulation of the virus. Human serum samples collected in Siena between 2016 and 2019 were tested for the presence of antibodies against West Nile virus by ELISA. ELISA positive samples were further evaluated using immunofluorescence, micro neutralization, and plaque reduction neutralization assays. In total, 1.9% (95% CI 1.2–3.1) and 1.4% (95% CI 0.8–2.4) of samples collected in 2016–2017 were positive by ELISA and immunofluorescence assay, respectively. Neutralizing antibodies were found in 0.7% (95% CI 0.3–1.5) of samples. Additionally, 0.9% (95% CI 0.4–1.7) and 0.65% (95% CI 0.3–1.45) of samples collected in 2018–2019 were positive by ELISA and immunofluorescence assay, respectively. The prevalence of neutralizing antibodies was 0.5% (95% CI 0.2–1.3). Although no human cases of West Nile infection were reported in the area between 2016 and 2019 and virus prevalence in the area of Siena Province was as low as less than 1%, the active asymptomatic circulation confirms the potential concern of this emergent virus for human health. Full article

(This article belongs to the Special Issue West Nile Virus Infection)

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15 pages, 2318 KiB

Open AccessArticle

Pathogenesis of Two Western Mediterranean West Nile Virus Lineage 1 Isolates in Experimentally Infected Red-Legged Partridges (Alectoris rufa)

by Virginia Gamino, Elisa Pérez-Ramírez, Ana Valeria Gutiérrez-Guzmán, Elena Sotelo, Francisco Llorente, Miguel Ángel Jiménez-Clavero and Ursula Höfle

Pathogens 2021, 10(6), 748; https://doi.org/10.3390/pathogens10060748 - 13 Jun 2021

Cited by 4 | Viewed by 2685

Abstract

West Nile virus (WNV) is the most widespread flavivirus in the world with a wide vertebrate host range. Its geographic expansion and activity continue to increase with important human and equine outbreaks and local bird mortality. In a previous experiment, we demonstrated the [...] Read more.

West Nile virus (WNV) is the most widespread flavivirus in the world with a wide vertebrate host range. Its geographic expansion and activity continue to increase with important human and equine outbreaks and local bird mortality. In a previous experiment, we demonstrated the susceptibility of 7-week-old red-legged partridges (Alectoris rufa) to Mediterranean WNV isolates Morocco/2003 and Spain/2007, which varied in virulence for this gallinaceous species. Here we study the pathogenesis of the infection with these two strains to explain the different course of infection and mortality. Day six post-inoculation was critical in the course of infection, with the highest viral load in tissues, the most widespread virus antigen, and more severe lesions. The most affected organs were the heart, liver, and spleen. Comparing infections with Morocco/2003 and Spain/2007, differences were observed in the viral load, virus antigen distribution, and lesion nature and severity. A more acute and marked inflammatory reaction (characterized by participation of microglia and CD3+ T cells) as well as neuronal necrosis in the brain were observed in partridges infected with Morocco/2003 as compared to those infected with Spain/2007. This suggests a higher neurovirulence of Morocco/2003, probably related to one or more specific molecular determinants of virulence different from Spain/2007. Full article

(This article belongs to the Special Issue West Nile Virus Infection)

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11 pages, 265 KiB

Open AccessArticle

First Autochthonous West Nile Lineage 2 and Usutu Virus Infections in Humans, July to October 2018, Czech Republic

by Hana Zelená, Jana Kleinerová, Silvie Šikutová, Petra Straková, Hana Kocourková, Roman Stebel, Petr Husa, Petr Husa, Jr., Eva Tesařová, Hana Lejdarová, Oldřich Šebesta, Peter Juráš, Renata Ciupek, Jakub Mrázek and Ivo Rudolf

Pathogens 2021, 10(6), 651; https://doi.org/10.3390/pathogens10060651 - 24 May 2021

Cited by 10 | Viewed by 2385

Abstract

We present epidemiological, clinical and laboratory findings of five Czech patients diagnosed with autochthonous mosquito-borne disease—four patients with confirmed West Nile virus (WNV) and one patient with Usutu virus (USUV) infections, from July to October 2018, including one fatal case due to WNV. [...] Read more.

We present epidemiological, clinical and laboratory findings of five Czech patients diagnosed with autochthonous mosquito-borne disease—four patients with confirmed West Nile virus (WNV) and one patient with Usutu virus (USUV) infections, from July to October 2018, including one fatal case due to WNV. This is the first documented human outbreak caused by WNV lineage 2 in the Czech Republic and the first record of a neuroinvasive human disease caused by USUV, which illustrates the simultaneous circulation of WNV and USUV in the country. Full article

(This article belongs to the Special Issue West Nile Virus Infection)

12 pages, 1310 KiB

Open AccessArticle

First Detection of the West Nile Virus Koutango Lineage in Sandflies in Niger

by Gamou Fall, Diawo Diallo, Hadiza Soumaila, El Hadji Ndiaye, Adamou Lagare, Bacary Djilocalisse Sadio, Marie Henriette Dior Ndione, Michael Wiley, Moussa Dia, Mamadou Diop, Arame Ba, Fati Sidikou, Bienvenu Baruani Ngoy, Oumar Faye, Jean Testa, Cheikh Loucoubar, Amadou Alpha Sall, Mawlouth Diallo and Ousmane Faye

Pathogens 2021, 10(3), 257; https://doi.org/10.3390/pathogens10030257 - 24 Feb 2021

Cited by 5 | Viewed by 2683

Abstract

West Nile virus (WNV), belonging to the Flaviviridae family, causes a mosquito-borne disease and shows great genetic diversity, with at least eight different lineages. The Koutango lineage of WNV (WN-KOUTV), mostly associated with ticks and rodents in the wild, is exclusively present in [...] Read more.

West Nile virus (WNV), belonging to the Flaviviridae family, causes a mosquito-borne disease and shows great genetic diversity, with at least eight different lineages. The Koutango lineage of WNV (WN-KOUTV), mostly associated with ticks and rodents in the wild, is exclusively present in Africa and shows evidence of infection in humans and high virulence in mice. In 2016, in a context of Rift Valley fever (RVF) outbreak in Niger, mosquitoes, biting midges and sandflies were collected for arbovirus isolation using cell culture, immunofluorescence and RT-PCR assays. Whole genome sequencing and in vivo replication studies using mice were later conducted on positive samples. The WN-KOUTV strain was detected in a sandfly pool. The sequence analyses and replication studies confirmed that this strain belonged to the WN-KOUTV lineage and caused 100% mortality of mice. Further studies should be done to assess what genetic traits of WN-KOUTV influence this very high virulence in mice. In addition, given the risk of WN-KOUTV to infect humans, the possibility of multiple vectors as well as birds as reservoirs of WNV, to spread the virus beyond Africa, and the increasing threats of flavivirus infections in the world, it is important to understand the potential of WN-KOUTV to emerge. Full article

(This article belongs to the Special Issue West Nile Virus Infection)

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16 pages, 1327 KiB

Open AccessArticle

Epidemiology and Clinical Presentation of West Nile Virus Infection in Horses in South Africa, 2016–2017

by Freude-Marié Bertram, Peter N. Thompson and Marietjie Venter

Pathogens 2021, 10(1), 20; https://doi.org/10.3390/pathogens10010020 - 30 Dec 2020

Cited by 14 | Viewed by 4012

Abstract

Although West Nile virus (WNV) is endemic to South Africa (RSA), it has only become recognized as a significant cause of neurological disease in humans and horses locally in the past 2 decades, as it emerged globally. This article describes the epidemiological and [...] Read more.

Although West Nile virus (WNV) is endemic to South Africa (RSA), it has only become recognized as a significant cause of neurological disease in humans and horses locally in the past 2 decades, as it emerged globally. This article describes the epidemiological and clinical presentation of WNV in horses across RSA during 2016–2017. In total, 54 WNV-positive cases were identified by passive surveillance in horses with febrile and/or neurological signs at the Centre for Viral Zoonoses, University of Pretoria. They were followed up and compared to 120 randomly selected WNV-negative controls with the same case definition and during the same time period. Of the WNV-positive cases, 52% had fever, 92% displayed neurological signs, and 39% experienced mortality. Cases occurred mostly in WNV-unvaccinated horses <5 years old, during late summer and autumn after heavy rain, in the temperate to warm eastern parts of RSA. WNV-positive cases that had only neurological signs without fever were more likely to die. In the multivariable analysis, the odds of WNV infection were associated with season (late summer), higher altitude, more highly purebred animals, younger age, and failure to vaccinate against WNV. Vaccination is currently the most effective prophylactic measure to reduce WNV morbidity and mortality in horses. Full article

(This article belongs to the Special Issue West Nile Virus Infection)

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20 pages, 1001 KiB

Open AccessArticle

Evaluation of West Nile Virus Diagnostic Capacities in Veterinary Laboratories of the Mediterranean and Black Sea Regions

by Elisa Pérez-Ramírez, Cristina Cano-Gómez, Francisco Llorente, Ani Vodica, Ljubiša Veljović, Natela Toklikishvilli, Kurtesh Sherifi, Soufien Sghaier, Amel Omani, Aida Kustura, Kiril Krstevski, Ilke Karayel-Hacioglu, Naglaa Mohamed Hagag, Jeanne El Hage, Hasmik Davdyan, Mohd Saddam Bintarif, Bojan Adzic, Nabil Abouchoaib, Miguel Ángel Jiménez-Clavero and Jovita Fernández-Pinero

Pathogens 2020, 9(12), 1038; https://doi.org/10.3390/pathogens9121038 - 11 Dec 2020

Cited by 6 | Viewed by 3082

Abstract

The increasing incidence of West Nile virus (WNV) in the Euro-Mediterranean area warrants the implementation of effective surveillance programs in animals. A crucial step in the fight against the disease is the evaluation of the capacity of the veterinary labs to accurately detect [...] Read more.

The increasing incidence of West Nile virus (WNV) in the Euro-Mediterranean area warrants the implementation of effective surveillance programs in animals. A crucial step in the fight against the disease is the evaluation of the capacity of the veterinary labs to accurately detect the infection in animal populations. In this context, the animal virology network of the MediLabSecure project organized an external quality assessment (EQA) to evaluate the WNV molecular and serological diagnostic capacities of beneficiary veterinary labs. Laboratories from 17 Mediterranean and Black Sea countries participated. The results of the triplex real time RT-PCR for simultaneous detection and differentiation of WNV lineage 1 (L1), lineage 2 (L2) and Usutu virus (USUV) were highly satisfactory, especially for L1 and L2, with detection rates of 97.9% and 100%, respectively. For USUV, 75% of the labs reported correct results. More limitations were observed for the generic detection of flaviviruses using conventional reverse-transcription polymerase chain reaction (RT-PCR), since only 46.1% reported correct results in the whole panel. As regards the serological panel, the results were excellent for the generic detection of WNV antibodies. More variability was observed for the specific detection of IgM antibodies with a higher percentage of incorrect results mainly in samples with low titers. This EQA provides a good overview of the WNV (and USUV) diagnostic performance of the involved veterinary labs and demonstrates that the implemented training program was successful in upgrading their diagnostic capacities. Full article

(This article belongs to the Special Issue West Nile Virus Infection)

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16 pages, 2101 KiB

Open AccessArticle

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

by Cécile Beck, Isabelle Leparc Goffart, Florian Franke, Gaelle Gonzalez, Marine Dumarest, Steeve Lowenski, Yannick Blanchard, Pierrick Lucas, Xavier de Lamballerie, Gilda Grard, Guillaume André Durand, Stéphan Zientara, Jackie Tapprest, Grégory L’Ambert, Benoit Durand, Stéphanie Desvaux and Sylvie Lecollinet

Pathogens 2020, 9(11), 908; https://doi.org/10.3390/pathogens9110908 - 30 Oct 2020

Cited by 26 | Viewed by 2807

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue West Nile Virus Infection)

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Review

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7 pages, 233 KiB

Open AccessEditor’s ChoiceReview

Animal and Human Vaccines against West Nile Virus

by Juan-Carlos Saiz

Pathogens 2020, 9(12), 1073; https://doi.org/10.3390/pathogens9121073 - 21 Dec 2020

Cited by 24 | Viewed by 3652

Abstract

West Nile virus (WNV) is a widely distributed enveloped flavivirus transmitted by mosquitoes, which main hosts are birds. The virus sporadically infects equids and humans with serious economic and health consequences, as infected individuals can develop a severe neuroinvasive disease that can even [...] Read more.

West Nile virus (WNV) is a widely distributed enveloped flavivirus transmitted by mosquitoes, which main hosts are birds. The virus sporadically infects equids and humans with serious economic and health consequences, as infected individuals can develop a severe neuroinvasive disease that can even lead to death. Nowadays, no WNV-specific therapy is available and vaccines are only licensed for use in horses but not for humans. While several methodologies for WNV vaccine development have been successfully applied and have contributed to significantly reducing its incidence in horses in the US, none have progressed to phase III clinical trials in humans. This review addresses the status of WNV vaccines for horses, birds, and humans, summarizing and discussing the challenges they face for their clinical advance and their introduction to the market. Full article

(This article belongs to the Special Issue West Nile Virus Infection)

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