Avian Influenza

About:

• Avian influenza is a disease caused by an influenza A virus, affecting birds across many species.
• It can have significant consequences for the poultry industry, due to its potential impact on bird health, production and even international trade.
• Although avian influenza does not usually infect people, it is considered a zoonotic virus. That means it can be transmitted to humans through contact with infected birds, and sporadic cases have been seen when outbreaks happen in poultry.
• Some avian influenza viruses are more pathogenic than others.
  • Pathogenic means disease-causing, so if highly pathogenic avian influenza gets into a poultry farm, it can cause sudden and significant mortality.
• Symptoms:
  • Avian influenza infections in humans can cause a range of clinical symptoms, from mild upper respiratory symptoms to severe pneumonia.
• Some strains of avian influenza, such as highly pathogenic H5N1 and H7N9, can cause significant disease in humans, and in some instances even death.
• Treatment:
  • Recommended standard treatment for humans is with antiviral drugs, and will depend on individual circumstances and severity of the symptoms.

Classification of Influenza:

• The influenza virus, which causes illness, is classified by WHO into four types: A, B, C, and D.
• According to the US Centers for Disease Control and Prevention (CDC), only the influenza A and B viruses are known to cause epidemics.
• The C type virus usually causes mild respiratory illness, while the D type virus typically affects cattle and is not known to infect humans.
• Only the influenza A virus is divided into subtypes and the subtype is based on two proteins on the surface of the virus, hemagglutinin (H) and neuraminidase (N).

Impact of influenza:

• Humans can be infected with avian, swine and other zoonotic influenza viruses, such as
  • Avian influenza virus subtypes A (H5N1), A (H7N9), and A (H9N2)
  • Swine influenza virus subtypes A (H1N1), A (H1N2) and A (H3N2)
• According to the WHO, influenza is known to affect 5-10% of adults and 20-30% of children across the world every year.