Persistent infection and associated nucleotide changes of West Nile virus serially passaged in hamsters.
Hamsters experimentally infected with the neuroinvasive West Nile virus (WNV) strain NY385-99 frequently develop persistent renal infection and viruria. Viruses recovered from the urine of such animals no longer cause neurological disease when inoculated into naïve hamsters. To examine if this phenotypic change is stable, and if additional nucleotide changes occur during further passages, a urine isolate from a persistently infected hamster (WNV 9317B) was serially passaged in hamsters, and representative isolates from each passage were analysed for pathogenesis in hamsters and by nucleotide sequencing. The progeny viruses tested all resulted in asymptomatic infection when inoculated into hamsters and caused no mortality. Most of the original nucleotide changes were retained in these serial WNV isolates. Changes were distributed throughout the genome at 116 sites, ranging from 0.082 to 0.262 %, compared with the parent strain NY385-99, and they were mostly in coding regions. Our findings indicate that WNV underwent additional genetic changes during serial passage in hamsters, but there was no reversion to neurotropism and virulence.
Wu
Xiaoyan
X
Department of Medicine, Zhong-nan Hospital, Wuhan University, Wuhan, Hubei Province, PR China.|Department of Pathology, and Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, USA.
Lu
Liang
L
Department of Pathology, and Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, USA.
Guzman
Hilda
H
Department of Pathology, and Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, USA.
Tesh
Robert B
RB
Department of Pathology, and Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, USA.
Xiao
Shu-Yuan
SY
Department of Pathology, and Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, USA.
D019943:Amino Acid Substitution; D000818:Animals; D002908:Chronic Disease; D006224:Cricetinae; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D009154:Mutation; D010641:Phenotype; D017422:Sequence Analysis, DNA; D012692:Serial Passage; D014556:Urine / Q000821:virology; D014774:Virulence; D014901:West Nile Fever / Q000401:mortality / Q000473:pathology* / Q000821:virology; D014902:West Nile virus / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*