Officials in at least one northeast Iowa county are dealing with an outbreak of whooping cough. Health officials have confirmed 21 cases of the disease in Black Hawk County. The disease — which doctors call pertussis — is spread through closes contact like kissing, sharing drinking glasses, or cigarettes. The disease initially seems like a common cold with a running nose. When it progresses, victims start coughing violently and begin to gasp for air. Teenagers and adults are the ones most-likely to spread the disease, according to doctors. Infants are most at-risk. Local health officials say the majority of the victims with confirmed cases of whooping cough in Black Hawk County are students at East and West High Schools in Waterloo. Friends and family members are also being treated. That means nearly 200 people are taking medication for whooping cough in the Cedar Valley.