The Centers for Disease Control and Prevention says Wisconsin leads the country in what could be the worst outbreak of whooping cough in more than five decades, the Wisconsin State Journal reports. Through July 5, Wisconsin had nearly 51 cases per 100,000 people -- nearly 10 times the national average.

The Minnesota Department of Health says 189 new cases of pertussis, also known as whooping cough -- have been confirmed in the state in the last week. That brings the total to more than 3,500 cases in the state this year.

The Minnesota Department of Health tells KARE 11 that there have already been 670 cases of whooping cough diagnosed in the state, which has already eclipsed the total amount of cases diagnosed in in Minnesota in 2011. Doctors are recommending tetanus booster shots to prevent new cases.

Minnesota's number of whooping cough cases continues to grow. The state confirmed about 400 new cases of whooping cough in the past month, raising the total in Minnesota to nearly 2,400 infections this year. The number of confirmed cases is the highest since vaccines were introduced in the 1950s.

Minnesota is one of several states dealing with a severe outbreak of the disease. Some 400 new cases have popped up in Minnesota this month. The people contracting the disease most often are older elementary school kids and middle schoolers.

The Minnesota Department of Health says a 12-year-old from Hennepin County and a 25-year-old woman from Olmstead County are the first two confirmed cases of 2012-2013 flu season.