Montana health officials have recorded 265 people sick with whooping cough so far this year with a new wave of cases in Gallatin County over the last week.

“For a little perspective, this time last year we were at 21 cases,” said Stacey Anderson, a state preventable disease epidemiologist with the Department of Public Health and Human Services.

People with the respiratory tract infection called pertussis often experience dry coughing. It’s an illness that spreads fast without intervention.

“This is a vaccine preventable disease,” Anderson said. “If a person is not up to date on their pertussis vaccine, it’s a good time to do so.”

The state’s tally of cases as of May 16 lapped last year’s total of 143. That has health workers behind the scenes trying to stop its spread.

Matt Kelley, public health officer with the Gallatin City-County Health Department, said 34 county residents were diagnosed with pertussis since January — a jump of seven cases in less than a week.

That includes a new Belgrade illness the department began investigating Tuesday.

“We’re seeing it community wide,” Kelley said. “We have cases at MSU, within the Bozeman School District, we have cases that don’t seem to be related to any of the above.”

That stands out from previous years where outbreaks were centralized.

Kelley said after the department learns of a new case, it finds people who could be exposed and in some cases, advises they get antibiotics to avoid the illness. He said people with symptoms should reach out to their doctor and get tested.

He said there are people who could face hospitalization or worse if they catch the infection. That includes babies who don’t yet have a vaccination, those with a weak immune system such as someone going through chemotherapy or someone with a pulmonary condition like asthma.

“We’re hoping for the best but planning for additional cases because I’m sure we’ll see them,” Kelley said. “We’re trying to build a wall of protection around the people who are most vulnerable.”

The situation isn’t the same statewide. Anderson said 16 counties reported pertussis cases since January with Missoula County leading the pack. But there’s concern that number will increase.

The infection typically has a spike in cases every three to five years. Kids in school have their last required pertussis vaccine in seventh grade. Anderson said it seems to have a weaning protection after roughly three to four years. She said so far this year, most Montanans with the infection have been between 16 and 18 years old.

Montana’s last pertussis peak happened in 2013 with 663 cases. Anderson said the illness resurfacing every few years is likely a perfect storm of its natural cycle and people who may be due for a vaccination.

“There’s some concern we’re kind of falling into that cycle,” she said.

Katheryn Houghton can be reached at or at 582-2628. Follow her on Twitter @K_Hought.

Katheryn Houghton is the city government and health reporter for the Bozeman Daily Chronicle.

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