Epi Corner: 2004 review

Epidemiology Corner

March 11 , 2005

Invasive GAS disease is a severe and sometimes life threatening infection in which the bacteria have invaded parts of the body, such as the blood, deep muscle and fat tissue or the lungs.

Two very serious diseases potentially caused by GAS are necrotizing fasciitis ("the flesh-eating bacteria") and streptococcal toxic shock syndrome (STSS). According to the Centers for Disease Control and Prevention (CDC), approximately 20 percent of patients with necrotizing fasciitis and 50 percent with STSS die while only about 10-15 percent of patients with other forms of invasive GAS disease die. Other forms of invasive GAS disease include meningitis (infection of the lining of the brain and spinal cord), endocarditis (infection of the heart), and osteomyelitis (infection of the bone).

The CDC estimated that approximately 9000 cases of invasive GAS disease occurred in the United States in 2002. Of these cases, 6 percent were necrotizing fasciitis and another 6 percent were STSS. These numbers are small when compared to over ten million annual cases of strep throat and impetigo. Fourteen cases of invasive GAS were reported in the city of Houston last year. These cases included meningitis, osteomyelitis and septicemia.

Very few people who come in contact with a virulent strain of GAS will develop invasive GAS disease; most will have a routine throat or skin infection and some may have no symptoms whatsoever. GAS bacteria are spread through direct contact with nose and throat secretions of an infected individual or with infected skin lesions. Breaks in the skin, like cuts, scratches or skin lesions such as those caused by chickenpox, may provide an opportunity for the bacteria to enter the body.

Although healthy people can get invasive GAS disease, people with chronic illnesses like cancer, diabetes and kidney dialysis, and those who use medications such as steroids, are at higher risk. In addition, there are certain strains of GAS that are more likely to cause severe disease than others.

Symptoms vary depending on the type of GAS infection. Early symptoms of necrotizing fasciitis include fever, severe pain, swelling, and redness at the wound site. Early symptoms of STSS may include fever, dizziness, confusion, low blood pressure, rash and abdominal pain. If these signs occur, especially in a person who also has a fever, consult a doctor immediately.

Persons with sore throats should also be seen by a physician, who can perform tests to find out whether it is strep throat.

GAS bacteria can be treated with common, inexpensive antibiotics.
Prevention of GAS infections:

Washing your hands after coughing, after sneezing and before food handling can greatly reduce to spread of several diseases including GAS.
Clean all wounds immediately. Even minor wounds should be watched closely for possible signs of infection which include increasing redness, swelling and pain at the wound site.
Consult a physician when fever accompanies a wound or sore throat. A person diagnosed with strep throat should stay home from work, school or daycare until at least 24 hours or more have passed after taking an antibiotic.

References:
http://www.niaid.nih.gov/factsheets/strep.htm
http://www.astdhpphe.org/infect/strepa.html
http://www.cdc.gov/ncidod/dbmd/diseaseinfo/groupastreptococcal_g.htm
http://www.health.state.mo.us/CDManual/CDsec40.pdf#search= 'invasive%20strepinfectedinfectious'
http://www.health.state.ny.us/nysdoh/communicable_diseases/en/gas.htm
http://www.nfsuk.org.uk/strep_A.htm