INDIANAPOLIS (AP) – Several Indianapolis hospitals are restricting visits by children to prevent the spread of a severe respiratory illness that has sickened hundreds of children nationwide.

The Indianapolis Star reports that starting Monday, Riley Hospital for Children at IU Health and Franciscan St. Francis Health will ban all neonatal intensive care unit visitors younger than 18, except for parents. Other IU Health hospitals in Indianapolis, Bloomington and Lafayette will also limit visitors. IU Health Goshen Hospital had already restricted visitors age 12 and under.

State health officials announced Friday that four children in Lake County had been confirmed as having enterovirus D68.

Enterovirus is similar to the germ that causes the common cold. The virus can be severe and require hospitalization in people with underlying medical conditions such as asthma.