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  Invasive Group A Streptococcus (iGAS)

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Invasive Group A Streptococcus (iGAS) disease is caused by Group A Streptococcus (GAS) bacteria, or Streptococcus pyogenes. These bacteria are often found in the throat or on the skin. They can spread from person to person through direct contact (e.g., contact with an infected wound or secretions from the mouth/nose of an infected person); and, through respiratory droplets (e.g., when an infected person coughs or sneezes). People can carry GAS bacteria without any symptoms, or they can develop different illnesses. Most GAS bacterial infections are mild, such as sore throat (referred to as “strep throat”) or skin infections, which can be called impetigo or cellulitis. 

Rarely, iGAS disease can occur when the bacteria gets into parts of the body where it is not normally found, such as in the blood, deep under the skin or in the muscle, or in the lining of the brain. In some cases, severe or life-threatening complications develop from iGAS such as: necrotizing fasciitis, (“flesh eating disease”), meningitis and, toxic shock syndrome.

Signs and symptoms of iGAS vary depending on where the infection is occurring and are often accompanied by fever. For example, symptoms of necrotizing fasciitis can include severe pain (worse than expected for the injury) and red swelling of tissue.

Risk of iGAS disease may be higher if a person has a chronic illness (e.g., cancer, diabetes) , weakened immune system, or has chickenpox. Risk of iGAS disease is also higher for children less than one year or adults over age 65 years, as well as people who inject drugs.

Medical treatment for iGAS includes appropriate antibiotics, and often requires hospitalization.

Page last reviewed:
Page last updated: 2019-01-08 10:16 AM
Uncontrolled print copy. Valid only on day of Print: [date]
Page updated on [date/time] 2019-01-08 10:16 AM
© , Ontario Agency for Health Protection and Promotion