Which statement about the relationship between low pathogenicity influenza (LPAI) and highly pathogenic avian influenza (HPAI) outbreaks is supported by the material?

Which statement about the relationship between low pathogenicity influenza (LPAI) and highly pathogenic avian influenza (HPAI) outbreaks is supported by the material?

• A. LPAI can be a source of HPAI
• B. LPAI cannot be a source of HPAI
• C. There is no relationship between LPAI and HPAI
• D. HPAI arises only spontaneously without prior LPAI

Answer: (A)

Low pathogenicity influenza (LPAI), especially certain subtypes like H5 and H7, can evolve into highly pathogenic avian influenza (HPAI). The key mechanism is mutation at the HA cleavage site, where the addition of multiple basic amino acids allows the HA protein to be activated by a broader range of proteases found in many tissues, enabling systemic infection and rapid, severe disease in poultry. This means LPAI strains can serve as the source from which HPAI outbreaks arise within bird populations, rather than HPAI appearing independently or spontaneously without prior LPAI. While not every LPAI strain becomes HPAI, and other factors can influence emergence, the material supports that LPAI can be a source of HPAI outbreaks.

Low pathogenicity influenza (LPAI), especially certain subtypes like H5 and H7, can evolve into highly pathogenic avian influenza (HPAI). The key mechanism is mutation at the HA cleavage site, where the addition of multiple basic amino acids allows the HA protein to be activated by a broader range of proteases found in many tissues, enabling systemic infection and rapid, severe disease in poultry. This means LPAI strains can serve as the source from which HPAI outbreaks arise within bird populations, rather than HPAI appearing independently or spontaneously without prior LPAI. While not every LPAI strain becomes HPAI, and other factors can influence emergence, the material supports that LPAI can be a source of HPAI outbreaks.