Two cases of pertussis, known as whooping cough, have been confirmed at Kalispell Middle School, the latest cases in what has been an active year for the infectious disease in Flathead County.

There have been 36 recorded cases of whooping cough across Flathead County in 2018, according to Lisa Dennison, an infectious disease prevention and control supervisor for the Flathead City-County Health Department.

The department sent an alert to school districts Thursday morning. Kalispell Middle School also released a statement to parents and guardians of its students.

“We have seen an increase of pertussis cases community-wide, which has impacted multiple schools throughout the county,” Dennison said.

However, pertussis is an illness that is cyclic in nature, meaning there will be expected peaks in disease cases every three to five years.

“This may be due to waning immunity, as neither infection nor immunization provides lifelong immunity,” Dennison said in an email.

The alert issued by the health department, categorized as a red high-alert, or one that “warrants immediate action or attention,” urges schools and families to watch for symptoms, which include runny nose, low-grade fever and mild to severe coughing.

The Centers for Disease Control and Prevention defines pertussis as a “highly contagious respiratory disease known for uncontrollable, violent coughing which often makes it harder to breathe.”

People of all ages are susceptible to pertussis, but it can be particularly harmful to elders, children and infants.

Should students exhibit symptoms, they should be excluded from school until they have “either tested negative for whooping cough, or antibiotic treatment is complete,” in an effort to limit the spread of pertussis.

Reporter Kianna Gardner may be reached at 758-4439 or kgardner@dailyinterlake.com.