Whooping cough epidemic declared in Wash. state - WKOW 27: Madison, WI Breaking News, Weather and Sports

SEATTLE (WKOW) -- Washington state's worst outbreak of pertussis in decades has prompted health officials to declare an epidemic.

State officials are seeking help from federal disease experts and are urging residents to get vaccinated amid worry that cases of the highly contagious disease are likely to spike much higher.

Washington is the first state to declare a whooping cough epidemic since 2010, when California had more than 9,000 cases, including 10 deaths. Washington has had 10 times the cases reported last year, and so has Wisconsin with nearly 2,000 cases this year, but that state has not declared an epidemic.

Washington health officials believe the state could see as many as 3,000 cases by year's end.

For more information on whooping cough protection in Wisconsin, click here.