Systematic Veterinary Virology

MORPHOLOGY

• The morphology of EIV is typical of Influenza virus A. They are pleomorphic enveloped viruses containing 8 segments of single stranded, negative sense, RNA.
• The virion consists of the viral ribonucleoprotein (RNA + NP) and polymerase complex (PA, PB1 and PB2) surrounded by the matrix proteins (M1 and M2) and a cellular lipid envelope containing 2 viral glycoproteins, the hemagglutinin (HA) and the neuraminidase (NA).
• The HA and NA contain the major neutralizing antigenic determinants of influenza viruses.