For the fourth time in less than two weeks, public health officials are warning the public of possible exposure to measles — this time involving a Santa Clara County resident who traveled to San Francisco via Caltrain, the San Francisco Department of Public Health said Tuesday.
The commuter, an adult contagious with measles while visiting San Francisco last week, was not hospitalized and is recovering at home, according to the San Francisco agency, which is working with the Santa Clara County Public Health Department to assist the measles-carrying individual and make sure residents and visitors from both counties are safe from the disease.
The Santa Clara County resident traveled on Caltrain during the morning commute on April 1 and evening rush hour on April 3.
On April 1, the individual sat in the first car (car 116) of northbound Caltrain train No. 319, where travelers were exposed to the virus sometime between 6:56-8:13 a.m. The train was then designated as southbound Caltrain train No. 232, where any travelers who boarded the same car (car 116) were exposed from roughly 8:45-9:15 a.m.
The individual stayed in San Francisco on April 2, spending a majority of the day at the Phillip Burton Federal Building in the city's Civic Center from 8 a.m. to 7:30 p.m. and visiting three eateries: Johnny Doughnuts from 8-9:30 a.m., Hayes Valley Bakeworks from 8-10 a.m. and Double Decker Restaurant from 6:30-8 p.m.
On the afternoon of April 3, the traveler visited the San Francisco Caltrain station at 700 Fourth St., where the public may have been exposed to measles sometime between 3-4:30 p.m.
The individual took southbound Caltrain train No. 258 that departed at 3:34 p.m. sitting in the second car from the back (car 3861), where exposure to measles ranged from 3:34-5:10 p.m. The train then transitioned to northbound service, Caltrain No. 279, where the exposure time in car 3861 ranged from 5:32-6:15 p.m.
While there is no outbreak and the public's risk of contracting the measles is low, San Francisco public health officials emphasized that people who aren't immune and visited the same places as the measles-carrying resident may develop the disease. Santa Clara County public health officials added that the measles virus can linger in the air a short time after the infected person has left a place.
Any child who hasn't received the measles vaccine, any adult born in 1957 or later without the vaccine or individuals with "severely weakened immune systems" should heed the warning, according to the public health department.
Most people are immune to the disease if they were given the measles vaccine as children, public health officials said.
Symptoms of the measles can appear seven to 21 days after exposure. They include fever, cough, runny nose and red eyes, which can lead to a red rash beginning on the head or face, according to public health officials. Anyone who experiences these conditions is advised to immediately contact their doctor.
The case doesn't appear to be related to others across the state. Public health agencies across the Bay Area have issued warnings of possible measles exposure since late March. In Santa Clara County, an international traveler visited 20 establishments, including six in the Palo Alto area, from March 16 through March 23. A second case was made public on March 29 involving a resident who contracted measles while traveling abroad. The two cases don't seem to be connected.
In Alameda County, patrons of Sauced BBQ & Spirits in Livermore may have been exposed to measles by a customer on March 23.