EFFECT OF TEMPERATURE ON THE STABILITY OF AVIAN INFLUENZA-VIRUS ANTIGENS UNDER DIFFERENT STORAGE-CONDITIONS

The combined effect of time and temperature on the stability of two av ian influenza virus (AIV) isolates concentrated with polyethylene glyc ol (PEG), stored at different temperatures, and used in the preparatio n of avian influenza vaccine was evaluated in turkeys at 24 hr and at 12, 24, 30, 36, and 42 months of storage. The differences detected bet ween antibodies raised in turkeys by vaccines made from isolates under different storage conditions, times, and temperatures were not signif icant (P > 0.05), especially with vaccines prepared from one isolate. Virus recovery rates following challenge studies of vaccinated birds w ere similar. However, birds that were vaccinated twice had lower rates of virus recovery from the trachea, lungs, pancreas, and fecal sample s following challenge infection. The results suggest that if stable is olates of AIV can be identified, such isolates can be rapidly concentr ated with PEG and stored at -20 C or -196 C for at least 42 months wit hout any loss of potency in the vaccine prepared from these isolates. This would reduce the costs associated with vaccine storage and subseq uent expiration dates.