BOISE -- Public health officials are warning of a whooping cough outbreak spreading across Ada and Canyon County.
Over the past four months, a total of 89 cases of whooping cough - also known as pertussis - have been reported. Seventy of those cases were in Ada County, and 19 were in Canyon County.
Whooping cough is an extremely contagious respiratory illness spread by coughing and sneezing, or other close contact with an infected person. The disease is particularly dangerous, and even life-threatening, for babies and young children.
In its earliest stages, the illness often causes cold-like symptoms including a runny nose and mild cough.
Later symptoms of the illness can include a high fever, headache, body aches and pains, extreme exhaustion and violent coughing that may be followed by gasping for air - often producing the "whooping" sound from which the sickness draws its name.
About 50 percent of babies under one year old who catch whooping cough end up in the hospital, according to the Central District Health Department. Symptoms are typically less severe in teens and adults, especially among those who are vaccinated.
Health officials are urging everyone to make sure they are up-to-date on the pertussis vaccine. The vaccines - DTap for children, and Tdap for teenagers and adults - are the best way to protect yourself and prevent passing the illness on to infants too young to receive the vaccine. Pregnant woman are advised to speak to their doctor about getting the Tdap vaccine.
Infected parents, siblings, and other caregivers can pass whooping cough on to infants without ever knowing they have the illness.
Although vaccines are the best defense against contracting whooping cough, health officials say, they may not provide perfect protection: About half of the recent pertussis cases in Ada County were in people who were already up-to-date on their vaccinations.
If you are already vaccinated but have a persistent cough or other symptoms, whooping cough is still a possibility.
Central District Health said whooping cough outbreaks tend to cycle, with peaks coming every three to five years. The last peak came in 2014-2015, when Ada and Canyon counties say nearly 300 cases of whooping cough.
The current outbreak began hitting Ada County back in October 2017, while Canyon County cases began increasing in January 2018.
Although pertussis can affect people of all ages, 13 to 18-year olds have been hit the hardest so far in the Treasure Valley. Cases have also been reported among 10-12 year olds, and adults between 19 and 39 years old.
The number of cases is expected to rise, since there is typically a gap between when people begin to feel sick and get in to see their doctor. Pertussis can be treated with antibiotics.