Serological studies of influenza in animals.

Reports have been published on the detection of antibodies in animals, including birds, to human influenza viruses. The work reported in this paper was undertaken in an effort to establish an effective method for differentiating specific antibody from non-specific antibody-like substances that occur naturally in serum.The primary antibody response of experimental animals exposed to influenza virus was readily differentiable from the secondary response following challenge of the animals with homologous viral antigen.Field challenge of cattle and sheep resulted in primary responses only, suggesting the non-antibody nature of inhibitor substances present in their sera prior to challenge.Challenge of swine and turkeys that had previously been involved in outbreaks of influenza resulted in secondary responses differentiable from the response of control swine and turkeys similarly challenged.The differentiation of non-specific substances from specific antibody by the challenge method used may help to clarify the role of animals in the epidemiology of human influenza.