East Coast mumps outbreak may be spreading to L.A.

A mumps outbreak on the East Coast — the largest in the United States in four years — may be spreading to Los Angeles County.

Nine cases of mumps have been reported so far this year, two more than were seen in all of 2009, according to county health officer Jonathan Fielding.

There is also a rise in whooping cough cases, which killed two infants in L.A. County this year, and an increase in measles cases to four so far in 2010, up from one last year.

“I’m always concerned when we see an increase in what has become a rare disease,” said Fielding, who added that the infant deaths were particularly disturbing.

Four of the mumps cases may be related to an outbreak, largely among Orthodox Jews, that has persisted in New York and New Jersey for almost a year. According to the New York State Department of Health, there have been more than 2,800 confirmed and probable mumps cases in New York and 315 in New Jersey.

The outbreak has also spread to Quebec, where 20 mumps cases have been linked to the New York outbreak, and to Israel, where more than 2,600 have been infected.

Dr. David Keene, a pediatrician in Beverly Hills, saw two mumps cases recently, involving a student who attends the private high school Yeshiva Ohr Elchonon Chabad in the Fairfax district of Los Angeles and a 2-year-old whose uncle attends the school.

“A lot of people went traveling at Passover, which was about six weeks ago. They went home and visited their friends with mumps, and three weeks later they got sick,” Keene said.

Health officials said the Orthodox Jewish community as a whole has high vaccination rates, which is limiting the outbreak’s size. The problem is that the vaccine is not completely effective. One dose is 73% to 91% effective; those who get a booster shot see 79% to 95% effectiveness.

“Sometimes, when mumps gets established somewhat in a community and you determine immunization rates are pretty high, sometimes it just has to run its course,” said Tom Skinner, a spokesman for the U.S. Centers for Disease Control and Prevention.

“The key is to go in and make sure vaccination rates are where they need to be to help . . . see the disease fester out sooner,” Skinner said.

The New York outbreak began in June 2009 when an unvaccinated 11-year-old boy visited Britain, where mumps outbreaks remain a problem. He then attended a summer camp in New York’s Sullivan County for Jewish boys. The disease, transmitted by coughing and sneezing, spread when the campers returned home.

The outbreak fits the profile of the last major U.S. mumps outbreak in 2006, spreading in places where people have prolonged, close contact.

Outbreaks have been notable at boys-only Orthodox Jewish schools, where students sit for long periods facing a study partner. Another reason could be the larger size of many Orthodox families, the CDC said.

Rabbi Chaim Cunin of Chabad of California, a Westwood-based Orthodox group, said his community has been monitoring the outbreak since last year.

“We live in a frequent-flier age. If the Jewish community on the East Coast has an issue, it’s certainly something we would monitor on the West Coast,” Cunin said. Private Jewish schools have been on a “heightened state of alert” to quickly send sick children home, he said.

Mumps, which causes fever, aches and fatigue, can also swell salivary glands, causing what are called “chipmunk cheeks.” Most people recover within 10 days.

Before the vaccine was released in 1967, about 186,000 people in the United States got the mumps every year, but the number has since fallen to fewer than 500 cases annually.

Keene said some of the rare complications of mumps include deafness and inflammation of the testicles. If that happens in males after adolescence, it could in rare cases cause sterility.

“People should all get their vaccines if they haven’t done so already,” Keene said.

In addition to the mumps cases, L.A. County this year has reported 73 possible cases of whooping cough, on track to exceed last year’s total of 155 cases. Fielding warned that adults can pass along whooping cough to infants too young to be immunized.

Health officials have been concerned about a drop in childhood vaccinations based on allegations, since discredited, that vaccines cause autism. The Times in 2009 reported that a rising number of California parents were choosing to send their children to kindergarten without routine vaccinations, putting hundreds of elementary schools in the state at risk for outbreaks of childhood diseases eradicated in the U.S. years ago.

ron.lin@latimes.com