5. Emerging virus infections

2018 ◽  
pp. 49-62
Author(s):  
Dorothy H. Crawford
Keyword(s):  
Yellow Fever ◽  
Rift Valley ◽  
Domestic Animals ◽  
Life Cycles ◽  
Virus Spread ◽  
Virus Infections ◽  
West Nile ◽  
Economic Implications ◽  
Emerging Virus ◽  
Contaminated Blood

Arboviruses are generally transmitted by small biting insects such as mosquitoes. These insects are not just passive carriers of the viruses, but are required by the viruses to complete their life cycles. So arboviruses cannot pass directly from one victim to another except rarely by transfusion of contaminated blood or transplantation of an infected organ. Nevertheless, these viruses are spreading widely, causing large epidemics in humans and domestic animals, with increasing morbidity, mortality, and severe economic implications. ‘Emerging virus infections: arthropod-transmitted viruses’ describes the yellow fever, Zika, Chikungunya, West Nile, dengue fever, and Rift Valley viruses. As the emergence and re-emergence of viruses is increasing, vaccines to protect both humans and domestic animals and to prevent virus spread are urgently needed.

scholarly journals Identification of Five Interferon-Induced Cellular Proteins That Inhibit West Nile Virus and Dengue Virus Infections

2010 ◽  
Vol 84 (16) ◽  
pp. 8332-8341 ◽  
Author(s):  
Dong Jiang ◽  
Jessica M. Weidner ◽  
Min Qing ◽  
Xiao-Ben Pan ◽  
Haitao Guo ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Antiviral Activity ◽  
Dengue Virus ◽  
Denv Infection ◽  
Life Cycles ◽  
Hek293 Cells ◽  
Virus Infections ◽  
West Nile ◽  
Antiviral Immune Response ◽  
Cell Plasma

ABSTRACT Interferons (IFNs) are key mediators of the host innate antiviral immune response. To identify IFN-stimulated genes (ISGs) that instigate an antiviral state against two medically important flaviviruses, West Nile virus (WNV) and dengue virus (DENV), we tested 36 ISGs that are commonly induced by IFN-α for antiviral activity against the two viruses. We discovered that five ISGs efficiently suppressed WNV and/or DENV infection when they were individually expressed in HEK293 cells. Mechanistic analyses revealed that two structurally related cell plasma membrane proteins, IFITM2 and IFITM3, disrupted early steps (entry and/or uncoating) of the viral infection. In contrast, three IFN-induced cellular enzymes, viperin, ISG20, and double-stranded-RNA-activated protein kinase, inhibited steps in viral proteins and/or RNA biosynthesis. Our results thus imply that the antiviral activity of IFN-α is collectively mediated by a panel of ISGs that disrupt multiple steps of the DENV and WNV life cycles.

scholarly journals Zika virus infections in Nigeria: virological and seroepidemiological investigations in Oyo State

1979 ◽  
Vol 83 (2) ◽  
pp. 213-219 ◽  
Author(s):  
A. H. Fagbami
Keyword(s):  
Yellow Fever ◽  
Zika Virus ◽  
Neutralizing Antibodies ◽  
Haemagglutination Inhibition ◽  
Febrile Illness ◽  
Neutralizing Antibody ◽  
Virus Infections ◽  
West Nile ◽  
High Prevalence

summaryA study of Zika virus infections was carried out in four communities in Oyo State, Nigeria. Virus isolation studies between 1971 and 1975 yielded two virus isolations from human cases of mild febrile illness. Haemagglutination-inhibition tests revealed a high prevalence of antibodies to Zika and three other flaviviruses used. The percentages of positive sera were as follows: Zika (31%), Yellow fever (50%), West Nile (46%), and Wesselsbron (59%). Neutralization tests showed that 40% of Nigerians had Zika virus neutralizing antibody. Fifty per cent of Zika virus immune persons had neutralizing antibody to Zika alone or to Zika and one other flavivirus. A total of 121 sera had antibody to Zika virus; of these 48 (40%) also showed antibody to two other flaviviruses, and 12 (10%) had antibodies to three or more other viruses. The percentage of neutralizing antibodies to other flaviviruses in Zika virus immune sera was 81% to Dengue type 1, 58% to Yellow fever, 7% to Wesselsbron, 6% to West Nile and 3% to Uganda S.

Locally temperature - driven mathematical model of West Nile virus spread in Germany

2020 ◽  
Vol 488 ◽  
pp. 110117
Author(s):  
Suman Bhowmick ◽  
Jörn Gethmann ◽  
Franz J. Conraths ◽  
Igor M. Sokolov ◽  
Hartmut H.K. Lentz
Keyword(s):  
Mathematical Model ◽  
West Nile Virus ◽  
Virus Spread ◽  
West Nile

West Nile and Usutu virus infections in wild birds admitted to rehabilitation centres in Extremadura, western Spain, 2017–2019

2021 ◽  
Vol 255 ◽  
pp. 109020
Author(s):  
Daniel Bravo-Barriga ◽  
Pilar Aguilera-Sepúlveda ◽  
Fátima Guerrero-Carvajal ◽  
Francisco Llorente ◽  
David Reina ◽  
...  
Keyword(s):  
Wild Birds ◽  
Virus Infections ◽  
West Nile ◽  
Usutu Virus ◽  
Western Spain

scholarly journals Epidemiology of West Nile Virus Infections in Humans, Italy, 2012–2020: A Summary of Available Evidences

2021 ◽  
Vol 6 (2) ◽  
pp. 61
Author(s):  
Matteo Riccò ◽  
Simona Peruzzi ◽  
Federica Balzarini
Keyword(s):  
West Nile Virus ◽  
Age Groups ◽  
Invasive Disease ◽  
Incidence Rates ◽  
Annual Incidence ◽  
Virus Infections ◽  
West Nile ◽  
Po River ◽  
Air Temperatures ◽  
Sex Risk

In Italy, human cases of West Nile virus (WNV) infection have been recorded since 2008, and seasonal outbreaks have occurred almost annually. In this study, we summarize available evidences on the epidemiology of WNV and West Nile neuro-invasive disease (WNND) in humans reported between 2012 and 2020. In total, 1145 WNV infection cases were diagnosed; of them 487 (42.5%) had WNND. A significant circulation of the pathogen was suggested by studies on blood donors, with annual incidence rates ranging from 1.353 (95% confidence intervals (95% CI) 0.279–3.953) to 19.069 cases per 100,000 specimens (95% CI 13.494–26.174). The annual incidence rates of WNND increased during the study period from 0.047 cases per 100,000 (95% CI 0.031–0.068) in 2012, to 0.074 cases per 100,000 (95% CI 0.054–0.099) in 2020, peaking to 0.377 cases per 100,000 (95% CI 0.330–0.429) in 2018. There were 60 deaths. Cases of WNND were clustered in Northern Italy, particularly in the Po River Valley, during the months of August (56.7%) and September (27.5%). Higher risk for WNND was reported in subjects of male sex (risk ratio (RR) 1.545, 95% CI 1.392–1.673 compared to females), and in older age groups (RR 24.46, 95% CI 15.61–38.32 for 65–74 y.o.; RR 43.7, 95% CI 28.33–67.41 for subjects older than 75 years), while main effectors were identified in average air temperatures (incidence rate ratio (IRR) 1.3219, 95% CI 1.0053–1.7383), population density (IRR 1.0004, 95% CI 1.0001–1.0008), and occurrence of cases in the nearby provinces (IRR 1.0442, 95% CI 1.0340–1.0545). In summary, an enhanced surveillance is vital for the early detection of human cases and the prompt implementation of response measures.

Rift Valley fever virus infections in Egyptian cattle and their prevention

2017 ◽  
Vol 64 (6) ◽  
pp. 2049-2058 ◽  
Author(s):  
C. Mroz ◽  
M. Gwida ◽  
M. El-Ashker ◽  
U. Ziegler ◽  
T. Homeier-Bachmann ◽  
...  
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Fever Virus ◽  
Virus Infections ◽  
Valley Fever

scholarly journals Different Cross-Reactivities of IgM Responses in Dengue, Zika and Tick-Borne Encephalitis Virus Infections

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 596
Author(s):  
Karin Stiasny ◽  
Stefan Malafa ◽  
Stephan W. Aberle ◽  
Iris Medits ◽  
Georgios Tsouchnikas ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Yellow Fever ◽  
Vaccination Coverage ◽  
Virus Infections ◽  
Recent Infection ◽  
Specific Diagnosis ◽  
Virus Particles ◽  
Tick Borne Encephalitis ◽  
Structural Peculiarities ◽  
Tick Borne Encephalitis Virus

Flaviviruses circulate worldwide and cause a number of medically relevant human diseases, such as dengue, Zika, yellow fever, and tick-borne encephalitis (TBE). Serology plays an important role in the diagnosis of flavivirus infections, but can be impeded by antigenic cross-reactivities among flaviviruses. Therefore, serological diagnosis of a recent infection can be insufficiently specific, especially in areas where flaviviruses co-circulate and/or vaccination coverage against certain flaviviruses is high. In this study, we developed a new IgM assay format, which is well suited for the specific diagnosis of TBE, Zika and dengue virus infections. In the case of TBE and Zika, the IgM response proved to be highly specific for the infecting virus. In contrast, primary dengue virus infections induced substantial amounts of cross-reactive IgM antibodies, which is most likely explained by structural peculiarities of dengue virus particles. Despite the presence of cross-reactive IgM, the standardized nature and the quantitative read-out of the assay even allowed the serotype-specific diagnosis of recent dengue virus infections in most instances.

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