Experimental production of respiratory tract disease in cebus monkeys after intratracheal or intranasal infection with influenza A/Victoria/3/75 or influenza A/New Jersey/76 virus.

A total of 28 cebus monkeys were inoculated intratracheally or intranasally with 10(6) 50% tissue culture infective doses of A/New Jersey/76 virus or 10(7) 50% tissue culture infective doses of A/Victoria/75 virus, and 8 additional monkeys received sterile allantoic fluid. Each of the animals became infected as evidenced by a serological response and/or shedding of the virus. Of the 10 animals inoculated intratracheally with A/Victoria/75 virus, 8 developed a systemic illness, and pulmonary infiltration was detected by X-ray in 7 of the 8. Administration of A/New Jersey/76 virus intratracheally to 10 monkeys produced a mild systemic illness in 2 animals and an upper respiratory tract illness in 6, but no illness developed in the remaining 2 monkeys; none of the animals developed X-ray evidence of lower respiratory tract disease. Intranasal administration of either virus failed to induce any illness or produced, at most, mild illness confined to the upper respiratory tract. These studies demonstrate that cebus monkeys are susceptible to respiratory tract infection with influenza A viruses and that the development of pulmonary disease is reflected in the appearance of easily recognizable radiological changes.