Climatic Controls on West Nile Virus and Sindbis Virus Transmission and Outbreaks in South Africa

2012 ◽  
Vol 12 (2) ◽  
pp. 117-125 ◽  
Author(s):  
Christopher K. Uejio ◽  
Alan Kemp ◽  
Andrew C. Comrie
Keyword(s):  
South Africa ◽  
West Nile Virus ◽  
Sindbis Virus ◽  
Virus Transmission ◽  
West Nile

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

Pathogens ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 20
Author(s):  
Freude-Marié Bertram ◽  
Peter N. Thompson ◽  
Marietjie Venter
Keyword(s):  
South Africa ◽  
West Nile Virus ◽  
Clinical Presentation ◽  
Multivariable Analysis ◽  
Late Summer ◽  
West Nile Virus Infection ◽  
Case Definition ◽  
West Nile ◽  
Prophylactic Measure ◽  
Neurological Signs

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.

scholarly journals West Nile Virus-Induced Neuroinflammation: Glial Infection and Capsid Protein-Mediated Neurovirulence

2007 ◽  
Vol 81 (20) ◽  
pp. 10933-10949 ◽  
Author(s):  
Guido van Marle ◽  
Joseph Antony ◽  
Heather Ostermann ◽  
Christopher Dunham ◽  
Tracey Hunt ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
West Nile Virus ◽  
Endoplasmic Reticulum Stress ◽  
Capsid Protein ◽  
Sindbis Virus ◽  
Tissue Injury ◽  
Ex Vivo ◽  
Neuronal Loss ◽  
Gene Induction ◽  
West Nile

ABSTRACT West Nile virus (WNV) infection causes neurological disease at all levels of the neural axis, accompanied by neuroinflammation and neuronal loss, although the underlying mechanisms remain uncertain. Given the substantial activation of neuroinflammatory pathways observed in WNV infection, we hypothesized that WNV-mediated neuroinflammation and cell death occurred through WNV infection of both glia and neurons, which was driven in part by WNV capsid protein expression. Analysis of autopsied neural tissues from humans with WNV encephalomyelitis (WNVE) revealed WNV infection of both neurons and glia. Upregulation of proinflammatory genes, CXCL10, interleukin-1β, and indolamine-2′,3′-deoxygenase with concurrent suppression of the protective astrocyte-specific endoplasmic reticulum stress sensor gene, OASIS (for old astrocyte specifically induced substance), was evident in WNVE patients compared to non-WNVE controls. These findings were supported by increased ex vivo expression of these proinflammatory genes in glia infected by WNV-NY99. WNV infection caused endoplasmic reticulum stress gene induction and apoptosis in neurons but did not affect glial viability. WNV-infected astrocytic cells secreted cytotoxic factors, which caused neuronal apoptosis. The expression of the WNV-NY99 capsid protein in neurons and glia by a Sindbis virus-derived vector (SINrep5-WNVc) caused neuronal death and the release of neurotoxic factors by infected astrocytes, coupled with proinflammatory gene induction and suppression of OASIS. Striatal implantation of SINrep5-WNVC induced neuroinflammation in rats, together with the induction of CXCL10 and diminished OASIS expression, compared to controls. Moreover, magnetic resonance neuroimaging showed edema and tissue injury in the vicinity of the SINrep5-WNVc implantation site compared to controls, which was complemented by neurobehavioral abnormalities in the SINrep5-WNVc-implanted animals. These studies underscore the important interactions between the WNV capsid protein and neuroinflammation in the pathogenesis of WNV-induced neurological disorders.

scholarly journals Lineage 2 West Nile Virus as Cause of Fatal Neurologic Disease in Horses, South Africa

2009 ◽  
Vol 15 (6) ◽  
pp. 877-884 ◽  
Author(s):  
Marietjie Venter ◽  
Stacey Human ◽  
Dewald Zaayman ◽  
Gertruida H. Gerdes ◽  
June Williams ◽  
...  
Keyword(s):  
South Africa ◽  
West Nile Virus ◽  
Neurologic Disease ◽  
West Nile ◽  
Lineage 2

scholarly journals Ecologic Factors Associated with West Nile Virus Transmission, Northeastern United States

2008 ◽  
Vol 14 (10) ◽  
pp. 1539-1545 ◽  
Author(s):  
Heidi E. Brown ◽  
James E. Childs ◽  
Maria A. Diuk-Wasser ◽  
Durland Fish
Keyword(s):  
United States ◽  
West Nile Virus ◽  
Virus Transmission ◽  
Northeastern United States ◽  
West Nile ◽  
Factors Associated ◽  
West Nile Virus Transmission

scholarly journals Genome sequence analysis of the first human West Nile virus isolated in Italy in 2009

2009 ◽  
Vol 14 (44) ◽  
Author(s):  
L Barzon ◽  
E Franchin ◽  
L Squarzon ◽  
E Lavezzo ◽  
S Toppo ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Genome Sequence ◽  
Virus Transmission ◽  
Whole Genome Sequence ◽  
Veneto Region ◽  
West Nile ◽  
Phylogenetic Relatedness ◽  
Neuroinvasive Disease ◽  
Human West Nile Virus ◽  
First Time

In 2009, six new human cases of West Nile neuroinvasive disease (WNND) were identified in Veneto region, following the six cases already reported in 2008. A human West Nile virus (WNV) isolate was obtained for the first time from an asymptomatic blood donor. Whole genome sequence of the human WNV isolate showed close phylogenetic relatedness to the Italy-1998-WNV strain and to other WNV strains recently isolated in Europe, with the new acquisition of the NS3-Thr249Pro mutation, a trait associated with avian virulence, increased virus transmission, and the occurrence of outbreaks in humans.

LarvicidingCulexspp. (Diptera: Culicidae) Populations in Catch Basins and Its Impact on West Nile Virus Transmission in Urban Parks in Atlanta, GA

2018 ◽  
Vol 56 (1) ◽  
pp. 222-232 ◽  
Author(s):  
Joseph R McMillan ◽  
Rebekah A Blakney ◽  
Daniel G Mead ◽  
Sarah M Coker ◽  
Levi T Morran ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Virus Transmission ◽  
Urban Parks ◽  
West Nile ◽  
West Nile Virus Transmission ◽  
Catch Basins
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