The number of measles cases in Whatcom County has increased to four, as the first person who was infected spread the disease to three other unvaccinated people in the same household, according to the Whatcom County Health Department.
"There was household spread, which is not unusual in these settings," said Dr. Greg Stern, Whatcom County health officer.
The family is in isolation. The initial case is past the transmission period for the disease, and the rest of the family should be out of isolation Wednesday, April 2.
The health department is keeping an eye on a few people who have been in close contact with the family so they can be isolated if symptoms begin.
The county cases are connected to a measles outbreak that was declared March 8 in Canada's Fraser Valley, where 320 confirmed cases have created British Columbia's largest outbreak of the disease.
Most of the cases were related to a religious group, called the Netherlands Reformed Congregation, that has a high number of unvaccinated children, according to the Vancouver Sun. The four local people who are infected live in Whatcom County but are part of that church community, Stern said.
Measles is a highly contagious disease that is spread primarily through coughing and sneezing. Anyone who has a fever and rash and thinks they might have measles should call ahead to the doctor so they can avoid exposing other people in the waiting room.
Public health officials are urging people who aren't immunized to get vaccinated.
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