how long can strep be contagious
Advertisement. Strep throat is a contagious disease caused due to Streptococcus bacteria. It is commonly found in children between the age group of 5 to 16 years. Strep throat can be contagious for 2 to 3 days if treated and more than a week if left untreated.ell, going further with the question how long is strep throat contagious after antibiotics, the answer is only till 24 hours after the intake of antibiotic. If strep throat is left untreated then it may be contagious for more than 10 - 15 days.