TABLE 3.

Pathogenic potential of H5N1/03 and -04 influenza viruses in mallards

Pathogenicity in ducksa and strainIVPIInfection routeNo. dead/ total no.Clinical signs of infection
Cloudy eyesNeurological signsb
Low-Pathogenicity Group
    A/Ck/HK/NT71/03NDcInoculated0/22/20/2
Contact0/21/20/2
    A/Ck/HK/AP111/031.96Inoculated0/21/20/2
Contact0/20/20/2
    A/Ck/HK/YU250/03NDInoculated0/20/20/2
Contact0/20/20/2
    A/Falcon/HK/D0028L/040.73Inoculated0/22/20/2
Contact0/21/20/2
    A/Ck/AH/85/041.76Inoculated0/20/20/2
Contact0/20/20/2
    A/Ck/PP/BPPV3/041.83Inoculated0/20/20/2
Contact0/20/20/2
    A/VN/3046/042.19Inoculated0/21/20/2
Contact0/21/20/2
    A/Thai/1(Kan-1)/040.39Inoculated0/20/20/2
Contact0/21/20/2
High-Pathogenicity Group
    A/Ph/HK/NT123/03NDInoculated1/21/21/2
Contact0/21/20/2
    A/Ck/HK/SSP94/03NDInoculated1/22/20/2
Contact0/22/20/2
    A/Ck/HK/WF27/03NDInoculated1/21/21/2
Contact0/22/20/2
    A/Ck/VN/133/04NDInoculated0/22/21/2
Contact1/11/10/1
    A/Ck/VN/48C/04NDInoculated1/21/20/2
Contact0/21/21/2
    A/Dk/VN/40D/04NDInoculated1/20/20/2
Contact0/22/20/2
    A/Pigeon/HK/WF32/03NDInoculated2/22/22/2
Contact2/22/22/2
    A/S.Ck/HK/YU17/03NDInoculated2/21/21/2
Contact2/20/20/2
    A/Ck/HK/YU46/03NDInoculated2/21/22/2
Contact2/21/21/2
    A/Ck/HK/SSP171/03NDInoculated2/20/20/2
Contact2/21/21/2
    A/S.Ck/HK/SSP7/03NDInoculated2/20/20/2
Contact2/21/22/2
    A/Mal/VN/16D/032.96Inoculated1/21/22/2
Contact1/10/20/1
    A/Ck/VN/C58/042.36Inoculated1/22/21/2
Contact1/20/20/2
    A/VN/1203/042.32Inoculated1/22/21/2
Contact1/22/21/2
    A/Dk/Thai/71.1/042.87Inoculated2/21/21/2
Contact2/20/21/2
  • a Pathogenicity groups were determined on the basis of lethality in both inoculated and contact ducks over a 14-day period following infection by the natural route. Low, no lethality; high, lethality in either inoculated or contact ducks.

  • b Neurological signs included twitching head, ataxia, violent tremors, severe torticolitis, and loss of balance.

  • c ND, not determined.