The Centers for Disease Control and Prevention has confirmed that Oregon has seen at least four cases of enterovirus in two different counties.
The country is in the middle of a nationwide outbreak of the respiratory illness.
Since mid-August, the CDC has confirmed that nearly 700 people have been infected in 46 states.
Infection can cause fever, a runny nose, sneezing, coughing and body aches. Severe symptoms may include wheezing and difficulty breathing.
It's spread when an an infected person coughs, sneezes or touches a surface that is then touched by others.
Those at risk include infants, children and teenagers, mainly because they haven't yet acquired immunity via previous exposure.
Enterovirus is seasonal and infections are expected to decline later in the fall.
Copyright 2014 Oregon Public Broadcasting