Systematic Veterinary Virology

STRAINS AND SEROTYPES

• The virus elicits distinct antigen determinants on envelope and spikes. Variations within the virus are due to differences in the S and HE proteins. As a result of this, these are many serotypes and within each serotype there are many strains. These serotypes are immunologically distinct (seropleurality; antigenic pleurality) and antibodies against one serotype may not protect the birds against the infection caused by other serotypes.
• Some of the common serotypes are Massachusetts, Connecticut, Arkansas etc. Some of the strains are M5, M41, H151, Holte, Gray, Florida etc.