Author
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King, Daniel |
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Submitted to: American Association of Avian Pathologists
Publication Type: Abstract Only Publication Acceptance Date: 6/1/2001 Publication Date: 7/16/2001 Citation: N/A Interpretive Summary: Technical Abstract: Chicken inoculation has been utilized since the 1950s to differentiate virulence among isolates of avian paramyxovirus-serotype 1 (APMV-1), a term synonymous with Newcastle disease virus (NDV). Three tests, the intracerebral pathogenicity index (ICPI), intravenous pathogenicity index (IVPI), and intracloacal inoculation have been employed to make that differentiation across the full spectrum of NDV virulence and clinical forms. Characterization of isolates as low (lentogenic), moderate (mesogenic), or high virulence (velogenic) were accomplished with that test battery. Because there is an international trend to separate APMV-1 isolates into two virulence groups, the lentogens and a more virulent group comprised of previous mesogenic and velogenic viruses, the role of the ICPI as a differential test has become emphasized. During 1999, that new emphasis was codified when member countries of the Office International des sEpizooties (OIE) approved a new definition of ND. ND is now defined by OIE as an infection with an APMV-1 of virulence measured by an ICPI of 0.7 or greater, a definition that expands those NDV isolates that present a risk to poultry beyond the previous velogenic classification. |
