Furthermore, it appears that HPAI viruses arise by mutation after LPAI viruses have been introduced to poultry Footnote 2. To date, only H5 and H7 subtypes have been shown to be HPAI, although not all H5 and H7 viruses are highly virulent Footnote 2 Footnote 3 Footnote 10. PATHOGENICITY/TOXICITY: Avian influenza A viruses are referred to as low pathogenic avian influenza (LPAI) and highly pathogenic avian influenza (HPAI), based on the severity of illness caused in poultry. Influenza pandemics may occur as a result of antigenic shifts if the virus is able to maintain efficient human-to-human transmission Footnote 1- Footnote 3. Small alterations are referred to as antigenic drift, whereas larger alterations caused by reassortment are referred to as antigenic shift. Antigenic alterations occur frequently in the antigenic sites of HA and NA and are the mechanism for virus adaptation and survival.

To date, 16 HA, and 9 NA subtypes have been detected in wild birds and poultry Footnote 5- Footnote 9. Type A influenza viruses are subdivided on the basis of the antigenic nature of their membrane-bound surface glycoproteins, haemagglutinin (HA) and neuraminidase (NA). SYNONYM OR CROSS REFERENCE: Orthomyxovirus Footnote 1- Footnote 3, influenza virus type A Footnote 1- Footnote 3, influenzavirus A Footnote 1- Footnote 3, avian influenza Footnote 1- Footnote 3, and pandemic influenza Footnote 4.ĬHARACTERISTICS: Influenza virus subtypes H5, H7 and H9 are members of the Orthomyxoviridae family of segmented, negative sense single-stranded RNA viruses. NAME: Influenza A virus subtypes H5, H7 and H9. PATHOGEN SAFETY DATA SHEET - INFECTIOUS SUBSTANCES SECTION I - INFECTIOUS AGENT

Dangerous by R.G. Alexander