Whopping number of whooping cough cases in Wisconsin

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• Pertussis primer

Three children who attend a Superior child care center have been diagnosed with pertussis, the latest report in a national outbreak of the disease that has hit Wisconsin particularly hard.

None of the three children, ages 3, 3 and 5, is ill enough to require hospitalization, said Rachel Johnson, Douglas County public health nurse. She said she could not identify the child care center or the number of children who attend for confidentiality reasons, but did say preventive antibiotics have been recommended for all children who have been at the center.

Pertussis, also known as whooping cough, is a highly contagious respiratory disease characterized by harsh coughing fits. Once a common childhood disease, it has become more sporadic since a vaccine was developed in the 1940s. It can afflict people of all ages, said Cynthia Kenyon, Minnesota Department of Health epidemiologist for pertussis and vaccine-preventable diseases. It can be fatal in infants but is serious at any age, she said.

“It certainly can be very serious in 11-year-olds,” Kenyon said, using the median age of Minnesotans with the disease. “They can have vomiting spells after coughing; coughing so hard that they’re not sleeping and coughing for two to three months. It’s not mild in adolescents.”

Minnesota has had more than 2,700 cases so far this year, compared with about 500 at this time last year, Kenyon said.

“What we’re seeing is the most cases since the late 1940s or early 1950s,” she added.

But the Minnesota numbers pale in comparison with Wisconsin, which has had 4,200 confirmed and probable cases so far this year, said Dan Hopfensperger, director of the immunization program for the Wisconsin Department of Health Services.

In fact, Wisconsin has far and away the highest incidence of whooping cough cases in the country this year, according to the Centers for Disease Control and Prevention, with 67.5 cases per 100,000 people as of Aug. 11. That compares with a national incidence of 7.36 per 100,000. It’s also far higher than the second-leading state: 49.2 cases per 100,000 people in Washington.

Minnesota ranks fourth, with 38.4 cases per 100,000.

The state of Washington declared a pertussis epidemic on April 3. Wisconsin has not followed suit, Hopfensperger said, although the disease is being treated seriously.

“We have not considered it to be an epidemic,” he said. “It’s a matter of semantics to a certain extent.”

In Wisconsin, as in Minnesota, early adolescents are the biggest age group afflicted by the disease this year, Hopfensperger said. That’s a concern with a new school year beginning.

“Fourth- and fifth-graders, they spend a lot of time together,” Kenyon said.

Several outbreaks have been associated with Northland schools within the past year. Six Ashland teenagers contracted the disease last December, just before the winter break. The tiny South Shore school district briefly shut down in February because of pertussis. And seven students in the Duluth school system’s Lakewood Elementary School were diagnosed with it in May.

Part of the reason for this year’s high numbers is that pertussis is cyclical, Hopfensperger said. The last uptick was from 2003 through 2005, and in 2004 Wisconsin had a total of about 4,500 confirmed and probable cases.

Another factor, both Hopfensperger and Kenyon said, could be an altered form of the pertussis vaccine that was introduced in the 1990s. The previous version caused high fevers in a few people, Kenyon said. The revised version is safer, but its effectiveness appears to wane faster than its predecessor.

Both officials said the pertussis numbers have dropped off in recent weeks, but they view that data with caution.

“That could be just a blip,” Hopfensperger said. “It’s too early to say we’re getting toward the end of it.”

Tags: news, health, wisconsin, minnesota, education, superior