Avian Influenza (H7n9) Update

— Written By James Parsons and last updated by

  I am sure most of you have heard about the H7N9 strain of avian influenza outbreak in China.  As of April 16, 2013, there were 63 cases of humans contracting the disease resulting in 14 deaths.  I hope the following information will calm your concerns.

 Avian influenza is a disease of wild birds and domestic poultry caused by many different subtypes of Type A influenza virus.  The natural reservoir for Type A influenza viruses is wild water birds such as ducks and geese.  New influenza A subtypes are continually emerging in the waterfowl population due to the constant mutation of the virus.

While avian influenza is caused by Type A viruses, seasonal influenza outbreaks in people, which occur almost every winter, are caused by either Type A or Type B influenza viruses.  Type C viruses cause a mild respiratory illness in humans, but are not usually responsible for outbreaks of the flu.  Type A viruses are found in both people and animals, whereas Type B viruses are normally only found in humans.

  Avian influenza viruses are classified in two ways.  One is by the host’s immune response and the other the severity of infection.  Influenza subtypes are named for two antigens present on the surface of the virus.  These are: H (hemagglutinin) and N (neuraminidase).  There are 16 possible H antigens and 9 possible N antigens.  Virus subtypes are named H9N2, H5N1, etc., depending on their combination of antigens.  The other classification of avian influenzas is by the severity of the disease in domestic poultry.  These designations are low pathogenicity avian influenza (LPAI) and high pathogenicity avian influenza (HPAI).

 So what is the concern about the H7N9 strain?  This influenza A is one subgroup among the large group of H7 viruses.  Although some H7 viruses (H7N2, H7N3 and H7N7) have occasionally been found to infect humans, until now H7N9 infections have not been reported in humans.  And as such a new virus, it has the potential to spark a pandemic due to the lack of immunity in the human population.

 Genetic sequencing of the virus indicates this virus has adapted to infect humans, grow and bind to mammalian cells.  As such, this virus is now able to grow in the lower temperature of the human body.  Although a couple of cases of human to human have been reported there is no evidence of sustained human-to-human transmission.

 You can reduce the risk of infection for this disease and other diseases just by following common sense practices.  Wash your hands before, during, and after you prepare food, before you eat, after using the toilet, after handling animals or animal waste, when dirty and when providing care when someone in your home is sick.  If possible use a disposable towel to open public doors, push shopping carts, etc.  Wash your hands with soap and running water or use an alcohol-based hand cleanser.

 You can further reduce the risk of infection by covering your mouth and nose with a medical mask, tissue, or a sleeve or flexed elbow when coughing or sneezing.  Throw the used tissue into a closed bin immediately after use and wash your hands.

 You may be wondering if it is safe to consume poultry and eggs.  These few common sense practices will protect consumers from H7N9 and other food-borne pathogens such as Salmonella: wash your hands with warm water and soap for at least 20 seconds before and after handling raw poultry and eggs, prevent cross contamination by keeping raw poultry and eggs away from other foods, do not use the same chopping block or utensils for raw meat and other foods, sanitize cutting boards by using a solution of 1 tablespoon of chlorine in 1 gallon of water, and use a food thermometer to ensure poultry has reached the safe internal temperature of 165 degrees Fahrenheit to kill food-borne germs including the avian influenza virus.

 REMEMBER, fully cooked or pasteurized eggs/egg products are safe to eat.  Fully cooked poultry (165 degrees Fahrenheit) is safe to eat. 

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