Health officials in Los Angeles County are warning about possible exposure to measles amid a spike in cases elsewhere in the country in recent months.

In late December, one person who was sick with the highly contagious viral infection visited several stores and restaurants in Malibu, Pasadena and Santa Monica while contagious, the Los Angeles Times reported.

Officials said there is no remaining risk in those areas, but people who may have been near the infected person should watch for any symptoms of the illness, which is spread through cough or sneeze and causes fever, red eyes and a rash. Most people who haven't been immunized will get measles if they are exposed to the virus, the Los Angeles County Department of Public Health said.

"If you think that you or someone you know has been exposed to or has measles, contact your healthcare provider by phone right away before going in," Dr. Muntu Davis, the county's health officer, said in a statement.

The alert comes amid a slew of measles outbreaks in recent months, nearly two decades after the disease was declared eliminated in the U.S.

New York, for example, has seen more than 160 cases since September and is experiencing what Dr. Howard Zucker, the state health commissioner, called "the largest measles outbreak that New York state has had in recent history," CNN reported.

In 2018, a total of 349 cases in 26 states and the District of Columbia were reported to the Centers for Disease Control and Prevention, up from 120 cases in 2017. A 2015 Disneyland-linked outbreak resulted in 147 cases and prompted California to strengthen its vaccine laws for school-age children.

Health experts say roughly 95 percent of people should be vaccinated to create "herd immunity" against a contagious disease like measles, and the CDC recommends children receive their first vaccination against measles between 12 and 15 months old. In 2017, measles vaccination coverage among children 19 to 35 months old was below 90 percent in 15 states, according to the CDC.

Globally, an uptick in cases, largely due to immunization gaps, "is of serious concern," Dr. Soumya Swaminathan, a World Health Organization official, said in a statement in November. While the measles vaccine has saved 21 million lives since the turn of the century, reported cases rose more than 30 percent from 2016 to 2017, according to the WHO.