[Zoonotic (avian) influenza. Prognoses of pandemic and reality]

Likelihood of a pandemic emergence in the near future was discussed. The majority of science-based arguments point to anthroponotic nature of future pandemic, which can be caused by return to circulation of H2N2 virus silently persisting in population from 1968 or in animals as part of various reassortants. Outbreaks of zoonotic (avian) influenza in humans emerged recently reflect natural epidemic manifestations of epizootic process which had become more intense due to specific social and natural conditions in densely populated countries of South-East Asia. This suggestion is confirmed by predominance of poultry workers between patients with avian influenza. Likelihood of pandemic influenza A virus emergence as a result of reassortation between human and avian influenza viruses is not high. Similarity of antigenic structure of human and animal influenza viruses points to their common roots, but yet humans remain the biological dead-end for reassortant viruses. Rationale for epidemiologic surveillance as well as for prophylactic and antiepidemic measures with respect to influenza A is obvious basing on anthroponotic nature of its causative agents. Although the likelihood of adaptation of animal influenza viruses to human organism and formation of anthroponotic mechanisms of transmission is small, epidemiological and, especially, epizootic surveillance for zoonotic influenza are essential.