Group A Strep (Invasive)

1,636 cases in 2024 — near the 5-year baseline of ~2,313.

What is it?

Invasive Group A Streptococcus (iGAS) disease occurs when the same bacteria that causes strep throat enters normally sterile body sites — bloodstream, lungs, muscles, and connective tissue. NYS had 1,636 cases in 2024. The two most feared forms are necrotizing fasciitis ("flesh-eating bacteria") and streptococcal toxic shock syndrome (STSS). iGAS infections require immediate hospitalization and are potentially fatal.

How it spreads

Spreads through respiratory droplets from infected people or through contact with infected wounds. Most invasive cases arise from the patient's own skin or throat bacteria entering a wound or the bloodstream. People with chickenpox are at higher risk for secondary iGAS infections.

Symptoms

Varies by site of infection. Bacteremia (bloodstream): high fever, severe illness. Necrotizing fasciitis: rapidly worsening, disproportionately severe pain at a wound site, followed by swelling, redness, and skin breakdown. Streptococcal TSS: sudden high fever, rapidly dropping blood pressure, and multi-organ failure.

Who is at risk?

Elderly adults, people with diabetes or chronic illness, people who inject drugs, and those with recent skin wounds or chickenpox. Close contacts of iGAS cases may be offered prophylactic antibiotics.

What you can do

Based on NYSDOH annual communicable disease report. Threat level reflects 2024 case counts compared to the 5-year baseline.