Strep throat is a common bacterial infection affecting the throat and tonsils. This highly contagious condition is caused by Group A Streptococcus bacteria, Streptococcus pyogenes. Understanding its spread helps manage the infection and limit transmission.
When Contagiousness Ends with Treatment
Once an individual with strep throat begins a course of antibiotics, contagiousness ends quickly. A person becomes non-contagious within 24 to 48 hours of starting treatment. This rapid reduction occurs because antibiotics kill the Streptococcus pyogenes bacteria.
Even if symptoms improve, completing the entire prescribed course of antibiotics is important. Stopping medication early can allow remaining bacteria to multiply, potentially leading to a return of symptoms or complications. The full course ensures the infection is cleared, minimizing the chance of complications and further spread.
Children can return to school or daycare after taking antibiotics for at least 24 hours and once their fever has subsided. This 24-hour mark is recognized as the point where the risk of transmission significantly decreases.
Contagiousness Without Treatment
If strep throat is not treated with antibiotics, an infected individual can remain contagious for a longer period. Without intervention, a person can continue to spread the Streptococcus pyogenes bacteria for several weeks, up to two to three weeks or longer. This extended period can persist even after initial symptoms have improved or disappeared.
Leaving strep throat untreated carries risks beyond prolonged contagiousness. Untreated strep throat can lead to serious complications, including rheumatic fever, which can affect the heart, joints, nervous system, and skin. Another potential complication is kidney inflammation, known as post-streptococcal glomerulonephritis. These complications highlight the importance of prompt diagnosis and treatment with antibiotics.
Practical Steps to Prevent Spread
Preventing the spread of strep throat and other respiratory infections involves consistent hygiene. Frequent handwashing with soap and water for at least 20 seconds is effective in removing bacteria. When soap and water are not available, an alcohol-based hand sanitizer can be used.
Covering coughs and sneezes with a tissue or into the elbow, rather than the hands, helps contain respiratory droplets that carry the bacteria. Avoiding the sharing of eating utensils, drinking cups, and other personal items is also an important measure. Regularly cleaning frequently touched surfaces, like doorknobs and tabletops, can help reduce the presence of bacteria in the environment.
An individual diagnosed with strep throat should stay home from work or school until they have been on antibiotics for at least 24 hours and are fever-free. This practice helps ensure they are no longer contagious before returning to group settings.