Experimental selection of virus derivatives with variations in virulence from a single low-pathogenicity H6N1 avian influenza virus field isolate.
A mixture of viruses with variations in virulence is likely present within a low-pathogenicity avian influenza virus (LPAIV) population. An H6N1 AIV was isolated from a field case showing 3.8% weekly mortality and a 33% egg production drop in Taiwan. The pathologic lesions included proventricular hemorrhage and urate deposition in the kidneys and on visceral organs. From the field isolate, a done (2838N) that caused no lesions or death was obtained using limit dilution in chicken embryos and a done (2838V) that caused renal lesions and death was obtained using contact infection in chicks. Both clones were inoculated intranasally in 4-week-old specific pathogen free (SPF) chickens to test their virulence. Renal urate deposition was found in chickens inoculated with 2838V but not in chickens inoculated with 2838N. In situ hybridization, polymerase chain reaction, and virus isolation were used to confirm the spread of 2838V from the respiratory tract to the renal tissue. We found that contact infection in chickens is a good method to obtain a more virulent done from a heterogeneous virus population.
Wang
Ching-Wen
CW
Department of Veterinary Medicine, National Taiwan University, Taipei 106, Taiwan.
Wang
Ching-Ho
CH
D000818:Animals; D001483:Base Sequence; D002645:Chickens; D017931:DNA Primers; D004196:Disease Outbreaks / Q000662:veterinary; D005260:Female; D009980:Influenza A virus / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity*; D005585:Influenza in Birds / Q000453:epidemiology*; D008297:Male; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D013624:Taiwan / Q000453:epidemiology; D014774:Virulence
D017931:DNA Primers