Four more cases of whooping cough, or pertussis, were reported over the weekend on South Whidbey.

“We now have 22 cases confirmed,” said Island County Medical Officer Dr. Roger Case. “I have advised principals of all island schools to be aware of the situation to make sure non-immunized children stay home from activities where they can come in contact with the disease.”

Case said he planned to contact the South Whidbey Parks & Recreation District with the same warning.

It takes 24 to 36 hours for a laboratory report to get back to a doctor’s office in order to confirm that whooping cough is present.

Case added that anyone having a persistent cough for more than a few days should consider the possibility they may have pertussis, which is spread by coughing.

Immunization, while not 100 percent effective, sharply reduces the chances for contracting the disease.

Case recommended that persons suspected of having pertussis should avoid contact with others until no longer contagious and take the full course of antibiotic treatment.

For information, visit www.islandcounty.net/health/pertussis. All cases of pertussis should be reported to the Island County Health Department at 360-679-7350.