Potential Measles Exposure Sites Include Calif. Target, Walmart

Two outbreaks of the measles virus that have infected at least 141 people have lead state and local health departments to release lists of the sites where residents might have been exposed to the virus in the hopes of curbing the outbreak.

In California, the San Bernardino County Health Department's list reveals how staples of the community, such as grocery stores or a Walmart, could be sites of potential infections and not just hospitals or schools with low vaccination rates.

Dr. William Schaffner, an infectious disease expert from Vanderbilt University Medical Center, said the range of potential infectious sites shows how important it is that every eligible person gets the measles vaccine.

The virus "can be in a house of worship, it can be at a theme park. It can really be anywhere," said Schaffner. "There doesn't have to be close contact through the measles source and the susceptible person," to get infected.

In San Bernardino, where nine people measles cases have been reported, the health department list reflects a variety of places where people could have been exposed to the measles virus, from Walmart to Target to a local sushi restaurant and chocolate store.

A Walmart spokesman told ABC News that company officials "take the safety of our customers and associates very seriously" and had instructed their associates, who were working when an infected person visited the store, to adhere to the health department's guidance.

A Target spokesman told ABC News that the company has posted a notice in the store and were working with local health officials.

The measles virus is among the most contagious viruses identified and can be transmitted four days before an infected person shows symptoms. By simply exhaling, an infected person can leave virus particles in the air that can infect anyone who does not have immunity.