CHICOPEE, Mass. (WWLP) – Experts are warning of a concerning increase in cases of strep throat in children across the United States.

It is typical to see a spike in strep throat cases between December to April, but many are saying this is the worst it has been in a long time. The infection is caused by the bacteria “Group A streptococcus.” This bacteria can cause a range of illnesses, from strep throat to scarlet fever.

Invasive strep is a rare condition that occurs when the bacteria spreads to parts of the body, like the bloodstream. Illinois has seen five pediatric deaths so far this year due to invasive strep.

Strep throat is most common among children ages 5 to 15. While it’s not very common in adults, some can be at higher risk. This includes parents of school-age children and adults who have a lot of contact with children.