Flathead County pertussis (whooping cough) cases have reached 59 and two new schools have been added to the list of those with students sick with the disease.

However, health officials say the outbreak may be ending.

On Monday, Jody White, director of Community Health Services at Flathead City-County Health Department, said that Edgerton and Elrod Elementary schools in Kalispell now had cases of the highly communicable disease sometimes called the 100-day cough.

The bacteria-based infection begins like a common cold but develops into a violent cough after 10 to 12 days.

Cases rose by three from last week. White said two of the new cases had no known connection to others in the county.

“We are certainly starting to see the end of the outbreak in Flathead County,” County Health Officer Joe Russell said.

“Preventing secondary infection by following the prescribed guidance is very important at this time.”

People with a cough lasting longer than one week should call their medical care provider. Anyone diagnosed with pertussis should not go to work, day care or public gatherings for five days after starting antibiotics.

Other preventive measures include vaccination of adults.

“We still highly recommend that, especially if they are going to be around infants,” White said.

Health officials say adults most often become the source of infection for children. Pertussis poses a particularly dangerous threat to infants who are too young for immunization and do not have naturally acquired immunities to fight infection.

Under a special program, the health department has immunizations available for  $15 for underinsured or uninsured people 19 or older who are going to be in contact with babies under the age of one year.

For more information, contact the health department at 751-8110 or a health care provider.

Reporter Candace Chase may be reached at 758-4436 or by email at cchase@dailyinterlake.com.