Strep throat is a common bacterial infection affecting the throat and tonsils, primarily caused by Group A Streptococcus (GAS) bacteria, also known as Streptococcus pyogenes. It can lead to a sore throat, fever, and difficulty swallowing. Understanding its spread is important for prevention.
How Strep Spreads Through the Air
Strep throat primarily spreads through respiratory droplets, not as a truly airborne disease. When an infected individual coughs, sneezes, talks, or sings, they release tiny droplets containing GAS bacteria into the air. These droplets are relatively large and heavy, so they do not remain suspended for extended periods or travel long distances. They typically fall to surfaces or are inhaled by individuals in close proximity, generally within 3 to 6 feet of the infected person.
This mechanism differs from true airborne transmission, where much smaller particles, known as droplet nuclei, can remain suspended for hours and travel greater distances, as seen with pathogens like measles or tuberculosis. While GAS can survive in aerosolized form, its viability is influenced by humidity and respiratory fluid composition. The primary concern remains transmission via larger respiratory droplets that settle quickly.
Other Ways Strep Can Spread
Beyond respiratory droplets, strep bacteria can also spread through direct contact with an infected person or contaminated surfaces. Direct contact includes sharing personal items like eating utensils, drinking glasses, or toothbrushes. Kissing can also facilitate direct person-to-person transmission.
The bacteria can also be transferred indirectly by touching surfaces or objects contaminated with respiratory secretions from an infected individual, then touching one’s own mouth, nose, or eyes. These contaminated surfaces, known as fomites, include doorknobs, toys, or other frequently touched items. Streptococcus pyogenes can survive on dry surfaces for varying periods.
Limiting the Spread of Strep
Preventing strep throat spread involves practicing good hygiene and being mindful of transmission routes. Frequent and thorough handwashing with soap and water for at least 20 seconds is effective, especially after coughing or sneezing and before eating. Alcohol-based hand sanitizers can be used when soap and water are not available.
Covering coughs and sneezes with a tissue or into the elbow helps contain respiratory droplets, preventing their spread. Avoid sharing eating utensils, cups, and other personal items. Cleaning and disinfecting frequently touched surfaces regularly can reduce indirect transmission from fomites. Staying home from school or work until at least 24 hours after starting antibiotic treatment is important to prevent further spread.