City health officials, linking a number of recent cases of measles to an outbreak in Israel, are urging New Yorkers planning international travel to make sure they have been vaccinated.

So far this year, the health department has identified 10 cases of measles, double the number in all of 2007 and the same as in 2000, the year officials said the city experienced its last measles “outbreak.”

Yesterday, officials emphasized that the recent cases — which occurred in February and March — did not constitute an outbreak. But they warned that New Yorkers traveling to Israel for the Passover holiday, or those hosting relatives from Israel, should be diligent about their immunizations.

There has been an outbreak of measles in Israel since last summer, and there have been outbreaks in parts of Europe, including Switzerland. The 10 New York City cases, which occurred in Brooklyn, were linked to overseas travel, health officials said. In at least two cases, the infected person was visiting New York from another country.

“The problem is not really here in the city in terms of more and more cases, but more people coming from overseas and bringing measles in,” the health department’s director of epidemiology and surveillance, Dr. Christopher Zimmerman, said. “When people travel and they’re not vaccinated, they can transmit disease,” he said.

Yesterday’s warning came a day after Nassau County health officials issued an advisory after learning that an Israeli baby exposed hundreds of people to measles at a mall on Long Island last week.

Among the New York City cases, at least one was similar.

In that instance, an Israeli baby with measles traveled to New York for a relative’s wedding in Brooklyn, but ended up in the emergency room at Maimonides Medical Center, according to a pediatric infectious diseases specialist there, Dr. Jason Perlman. The baby’s doctor in Israel had approved the family’s travel plans, but the infant developed a rash — indicating measles — on the airplane, Dr. Perlman said.

“We don’t see it on a regular basis. It’s something you learn about in the textbooks a lot,” Dr. Perlman, who treated three cases of measles in children this year, said. In all three, the hospital notified the health department immediately.

Measles is not common in developed countries, where babies typically receive the MMR vaccine against measles, mumps, and rubella around their first birthday.

In New York City, health officials said 94% of children have been vaccinated.

Health experts said travel, particularly to developing countries, presents a risk. “There’s no question that increased travel has raised a whole range of risks,” a professor of clinical epidemiology at Columbia University’s Mailman School of Public Health, Salim Abdool Karim, said. “You see the kinds of steps that are taken to prevent avian flu or SARS, for that matter, because you’ve got whole populations who are at risk.”

Dr. Zimmerman said officials plan to work with community leaders in Brooklyn and particularly in the Boro Park neighborhood, where there have been a number of cases. “At this time we’ve had more cases around that part of Brooklyn, so that’s where our efforts have been focused,” Dr. Zimmerman said. He stressed the issue was not limited to one neighborhood. “With Passover coming, this really is a citywide issue,” he said.