Invasive Group A Streptococcal Disease

What is group A streptococcus?

Group A streptococci (GAS) are bacteria commonly found in the throat and on the skin. The vast majority of GAS infections are relatively mild illnesses, such as strep throat and impetigo. Occasionally, these bacteria can invade the blood, deep muscle, fat tissue or the lungs and cause severe and even life threatening diseases.

What are the invasive group A streptococcal diseases?

Two of the most severe forms of invasive GAS disease are called necrotizing fasciitis (infection of muscle and fat tissue) and streptococcal toxic shock syndrome; a rapidly progressing infection causing low blood pressure/shock and injury to organs such as the kidneys, liver and lungs.

How common is invasive group A streptococcal disease?

There was an average of 877 cases per year reported in Canada from 2000 to 2004. In 2004 Newfoundland & Labrador reported four cases of invasive GAS.

Why does invasive group A streptococcal disease occur?

Invasive GAS infections occur when the bacteria get past the defenses of the person who is infected. This may occur when a person has sores or other breaks in the skin that allow the bacteria to get into the tissue, or when the person’s ability to fight off the infection is decreased because of chronic illness or an illness that affects the immune system. Also, some virulent strains of GAS are more likely to cause severe disease  than others.

Who is most at risk of getting invasive group A streptococcal disease?

Few people who come in contact will develop invasive GAS disease. Most people will have a throat or skin infection, and some may have no symptoms at all. Persons with skin lesions (such as cuts, chicken pox, and surgical wounds), the elderly, and adults with a history of alcohol abuse or injection drug use have a higher risk for the disease.

Can invasive group A streptococcal disease be treated?

Prompt medical attention and antibiotics are recommended for the treatment of invasive GAS. Severe cases may require supportive care in the intensive care unit. Treatment of necrotizing fasciitis usually requires surgical interventions.

Should contact with individuals with invasive group A streptococcal disease be tested and treated?

The risk of secondary cases of invasive GAS disease is very small. The medical officer of health will provide recommendations for the follow-up of contacts.

What can be done to prevent invasive group A streptococcal infections?

The spread of all types of GAS infections may be reduced by good hand hygiene practices. All wounds should be kept clean. Wounds should be watched for possible signs of infection which include redness, swelling and pain at the wound site. If these signs occur, especially in a person with a fever, consult a doctor immediately. Routine childhood immunization with varicella (chicken pox) vaccine is also recommended.

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Last updated: 2024-04-24