An outbreak of mumps that started at an Idaho university and infected 21 people across the state has now spread to neighboring Washington state, health officials said on Monday.
The spread of mumps, a highly contagious virus that leads to painful swelling of the salivary glands, comes as a wider measles outbreak has infected more than 100 people in California and over a dozen more in 19 other U.S. states and Mexico since December.
The mumps outbreak began in September at the University of Idaho campus in Moscow, near the border with Washington state, and later spread to the capital, Boise, the Idaho Department of Health and Welfare said.
Mumps, which leads to painful swelling of the salivary glands, spreads easily from sharing saliva through kissing, shared eating utensils or water bottles, public health officials said.
So far, there have been 21 confirmed and probable cases, including six around Boise, the state's most populous city, a statement said. Then on Friday, two infections were reported in Washington state, the statement added.
Public health officials were urging students on the Moscow campus and anyone who might have come into close contact with an infected person to ensure their vaccinations are up to date. Mumps and measles can be prevented through a single vaccine, the MMR vaccine that also covers rubella, health officials said.
"The MMR vaccine will also protect against measles, which is increasing in the western U.S. because of a large outbreak linked to an amusement park in California," the Idaho health agency said in a statement.
The measles outbreak has renewed debate over the so-called anti-vaccination movement, in which a small minority of parents have chosen not to immunize their children over fear of potential side-effects fueled by now-debunked research suggesting a link to autism. Federal health officials have urged parents to get their children vaccinated.