EL PASO, Texas (KTSM) – A woman in her late 40’s and a toddler boy have tested positive for measles and El Paso health officials are warning residents who may have come into contact with them.

The City of El Paso Department of Public Health is asking anyone who visited the following places at the time listed to review his or her immunization status.

Thu, June 27: Neighborhood Walmart (10301 Alameda) from 1 p.m. to 5 p.m.

Fri, June 28: Subway at Ft. Bliss (1333 Cassidy) from 5 p.m. to 7 p.m.

Sat, June 29: Bassett Place Mall-Target, Kohl’s, Jewelry Box from 6 p.m. to 9 p.m.

Sun, June 30: Ft. Bliss PX, Exchange, Food Court from noon to 4:30 p.m.

Mon, July 1: Walmart at Americas (9441 Alameda) from 4 a.m. to 6 a.m.

If you were at these locations and develop a fever and rash, you should call your doctor immediately, health officials said in a news release.

“Measles is so contagious that someone who has the disease should expect that 90 percent of the people around them, who are not immune, could become infected,” said Bruce Parsons, Assistant Public Health Director. “There is a 9-day window of time, four days before and four days after the onset of the rash where the disease can be spread. This is why we need residents who may have unknowingly come into contact with these individuals to be especially vigilant in identifying any symptoms they may have.”

An investigation is being conducted to determine if there is a link between the two patients, the release said.

“It should be noted that in El Paso, by the time children enter school in El Paso, 95.4% of the student population have been fully immunized with the MMR (measles, mumps, and rubella) vaccine. Two doses of this vaccine are 97% effective against measles.”

The last time measles was confirmed in El Paso was 1993 and the last time there was an outbreak was 1990.

For more information on measles and the vaccine, you can visit https://www.cdc.gov/measles/about/index.html.