An unvaccinated child from Nevada County has been diagnosed with measles, and has exposed "many" people, including unvaccinated classmates, to the highly contagious disease, the California Department of Public Health said Tuesday.
The child showed symptoms - which can include a fever, cough and a rash over much of the body - after returning to California from travel overseas, said State Public Health Officer Dr. Karen Smith.
The child attends Yuba River Charter School and was infectious while at school on March 17, according to the Nevada County Public Health Department. The department says it's working with the school to notify parents that their kids may have been exposed to the disease.
Children have a higher risk of contracting measles if they are not fully vaccinated. At Yuba River Charter School, 26 of 61 new kindergartners - 43 percent - were up-to-date on their vaccinations as of last fall, according to the state Department of Public Health.
The child has fully recovered, and Public Health is investigating the case, Smith said.
"It's concerning to receive a report of a child with measles because it's a disease that can easily be prevented," Smith said. "Immunization is the best way to protect against measles."
This is the second confirmed case of measles in California this year, according to a state Public Health spokesman. The first case was also acquired during travel overseas. That person did not infect any others.
Measles is highly contagious; it's spread through the air when an infected person coughs or sneezes. People who contract it are usually contagious for about nine days, including the four days before the rash starts.
The disease can lead to complications such as diarrhea, ear infections and pneumonia. Severe complications can be fatal. Infants, pregnant women and people with compromised immune systems are more at risk of complications.
Before the development of a vaccine in the 1960s, measles sickened millions and killed thousands of Americans. It was declared eliminated in the U.S. in 2000, although it remains a scourge in some countries. The Centers for Disease Control and Prevention estimates that measles still kills 146,000 people worldwide every year.
California has experienced a few measles outbreaks since 2000. They are typically started by people who contracted the disease abroad. Public health experts believe last year's outbreak, which began at the Disney theme parks in Anaheim in Dec. 2014, started when a tourist imported the disease from overseas. It spread quickly, especially among people who were not vaccinated.
The outbreak helped lead to a new law that requires all students in California to be vaccinated unless they have a medical exemption. State Senator Richard Pan (D-Sacramento), who wrote the law, said the Nevada County case underscores the need for his legislation.
"When schools begin to implement the new law this fall and more children are vaccinated, we will begin to boost our immunity levels which have declined to dangerously low levels in many communities in the state," Pan said.
Experts recommend school-aged children receive two doses of the MMR vaccine, which protects against measles, mumps and rubella. They recommend kids get their first dose at 12 to 15 months of age, and their second dose at four to six years of age.
Smith noted that two doses of the MMR immunization "are approximately 97 percent effective at preventing disease in exposed persons."
This story has been updated.