COMPARISONS OF INFLUENZA VIRUS STRAINS FROM THREE EPIDEMICS

Area of Science:

• Virology
• Epidemiology
• Immunology

Background:

• Influenza A and B viruses cause seasonal epidemics.
• Understanding viral characteristics is crucial for effective prophylaxis.

Purpose of the Study:

• To describe peculiarities of influenza A and B virus strains from two epidemics.
• To compare isolation, adaptation, and antigenic properties of these strains.

Main Methods:

• Isolation of influenza viruses from human sources.
• Adaptation studies in chick embryos and mice.
• Storage stability assessment at -72°C.
• Antigenic pattern comparison using serological methods.

Main Results:

• Influenza B virus was significantly harder to isolate and adapt than influenza A.
• Influenza B showed better amniotic than allantoic growth adaptation.
• Influenza B strains did not primarily exhibit O form characteristics.
• Minimal antigenic differences were observed among influenza A strains within and between epidemics.
• Influenza B strains from the 1945-46 epidemic showed no significant strain differences.

Conclusions:

• Influenza B virus exhibits distinct biological properties compared to influenza A.
• The lack of significant antigenic drift in both A and B strains has implications for influenza prophylaxis strategies.