Health officials say the number of pertussis cases in South Dakota is on the rise.
The Department of Health says that while the state saw 67 cases last year, 29 have been reported in the first five months of 2014.
Pertussis is also known as whooping cough. It's a highly contagious disease that's spread through the air by cough.
The department says there are several suspected cases and many close contacts. A disproportionate number of cases have been reported in the Black Hills area.
Early symptoms resemble a common cold. The cough becomes more severe within two weeks and is characterized by episodes of numerous rapid coughs followed by a crowing or high pitched whoop.
Officials are urging parents to make sure their children are vaccinated against the disease.