According to the County of Santa Clara Public Health Department, the tourist made 20 stops across the South Bay between March 16 and the 22.
RELATED: Officials: Santa Clara Co. tourist with measles may have been contagious
Dr. Sara Cody, Public Health Director for Santa Clara County explained, "The time that the infected person was at each location was not very long, but there were numerous locations.
Dr. Cody stressed the alert is not a public health emergency. She said the vast majority of people in the county are vaccinated against virus and are protected.
Still, the measles is a highly contagious respiratory disease that can be transmitted from one person to another through the air.
"It doesn't have to be face to face contact, it's just sharing the same air space," Cody said. "Or even being in the air space after an infectious person has been there."
"Since the weather is changing, you don't know if it's going to be just a cough, or if it's going to be that," Andrea Fuentes told ABC7 News. "It's kind of scary, it's kind of concerning... Really concerning actually."
Fuentes was visiting the Walmart in Mountain View which made the list of possible exposure locations. At her side was her 3-year-old daughter, who she says is with her all the time.
"It's concerning that she's here with me and it could be possibly contagious," she said.
Fuentes said her concern surrounds the fragile immune systems of young children.
County health officials addressed the population most susceptible to contracting the disease.
At a press conference on Tuesday, Dr. Cody said, "Some people are not protected from measles, and at the top of that list are babies, because they're too young to be vaccinated.
She added, "If a family happened to be traveling with their baby to one of these places where the infectious person was, they should be watching for symptoms."
Symptoms include a rash, fever, cough, runny nose and red eyes. They can develop anywhere from seven to 21 days after exposure.
The department provided the following list of places visited by the infected tourist:
Saturday, March 16
- T Mobile Store, 789 El Camino Real, Sunnyvale 9 - 11 a.m.
- International House of Pancakes, 644 North First St, San Jose 9:30 a.m. - noon
- Apple Visitor Center, 10600 N Tantau Ave, Cupertino 11 a.m. - 1:30 p.m.
- Hoover Tower Observation Deck, Stanford University, 550 Serra Mall, Stanford 12:30 - 3:30 p.m.
- Poki Bowl, 2305 El Camino Real, Palo Alto 1:30 - 4 p.m.
- Walmart, 600 Showers Dr, Mountain View 3 - 5 p.m.
- The Fish Market, 3775 El Camino Real, Santa Clara 4 - 6:30 p.m.
- Macy's Valley Fair Mall, 2801 Steven's Creek Blvd, Santa Clara 6 - 8 p.m.
Sunday, March 17
- Bill's Café, 3163 Middlefield Rd, Palo Alto 9:30 a.m. - 12:30 p.m.
- Cascal, 400 Castro St, Mountain View 6 - 9 p.m.
- 7-Eleven, 848 E. Evelyn Ave, Sunnyvale 7:30 - 9:30 p.m.
Monday, March 18
- Il Fornaio (Cucina Italiana), 2752 Augustine Dr, #120 Santa Clara 7 - 10 p.m.
- 7-Eleven, 848 E. Evelyn Ave, Sunnyvale 10 - 11:30 p.m.
Tuesday, March 19
- Great Mall, 477 Great Mall Drive, Milpitas 7 - 9:30 p.m.
- Seniore's Pizza, 940 Monroe St, Santa Clara 9:30 - 11 p.m.
Wednesday, March 20
- SA-BY Thai Cuisine, 404 S. 2nd St, San Jose 7 - 9:30 p.m.
- Lucky, 3705 El Camino Real, Santa Clara 9 - 10:30 p.m.
Thursday, March 21
- CVS Pharmacy, 1165 El Camino Real, Sunnyvale 7:30 - 9:30 p.m.
Friday, March 22
- Safeway, 645 San Antonio Rd, Mountain View 4:30 - 6:30 p.m.
- CVS Pharmacy, 1675 Hollenbeck Ave, Sunnyvale 5:30 - 7:30 p.m.