Whooping cough cases keep soaring in the central San Joaquin Valley and statewide, and the worst may not be here yet.

California is facing what could be the state’s biggest outbreak of pertussis since 1958, according to its top public health official. This contagious disease is more commonly known as whooping cough due the distinctive whoop that occurs when sufferers cough and gasp for breath.
Pertussis has increased dramatically, and can be deadly to infants.

Fresno County reported 229 cases of the whooping cough or pertussis last week. In 2009, the county had a total of 27 cases for the entire year, health officials said.

The increase in cases mirrors that being seen statewide. California had 910 reported whooping cough cases as of Friday–already a four-fold increase from 2009, officials with the Department of Public Health said. And an additional 600 suspected cases are being investigated, the officials said.

“Whooping cough is now an epidemic in California,” said Dr. Mark Horton, director of the California Department of Public Health, in a statement. “Children should be vaccinated against the disease and parents, family members and caregivers of infants need a booster shot.”

The number of pertussis cases is now on a pace to surpass the total of 3,182 seen in the most recent major outbreak, which occurred in 2005, said Ken August, spokesman for the department.

August told MedPage Today that 1,200 cases were recorded in 2005 as of mid-June, meaning the state would probably exceed that this year.

The highest yearly total on record is 3,837 cases, seen in 1958.

So far this year, five children have died, all infants younger than three months.

Dr. Blaise Congeni of Akron Children’s Hospital in Ohio said he wasn’t surprised, as higher-than-usual numbers of pertussis cases have been reported across the country.

“We are having an outbreak in Ohio,” though not as severe as in California, he said.

Oregon public health officials have also reported an unusually high number of pertussis cases in that state.

Both Congeni and August noted that pertussis tends to wax and wane in cycles. But gaps in vaccination coverage may also be playing a role, particularly in California.

Whooping cough is highly contagious and is spread from person to person through droplets from coughs and sneezes. Infants are especially vulnerable to infection and complications.