The measles outbreak in West Texas is linked to cases in New Mexico, as well as new cases reported in Oklahoma.

That brings the total number of cases to 258 in three states, officials said.

In West Texas, 223 cases have been reported, according to the March 12 update from the Texas Department of Health - 25 more confirmed cases since the March 7 update, CNN reports.

New Mexico reported 33 measles cases, three more than last week, and said it now believes the outbreak there is linked to the one in West Texas.

"We believe this is a regional measles outbreak that is linked geographically and through the strain identified through genome sequencing," said Robert Knott, communications director for the New Mexico Health Department.

Two measles cases have also been reported in Oklahoma.

Infected people report "exposure to risk associated with the outbreak in Texas and New Mexico."

Even with the rising number of cases, experts say those numbers are greatly understated.

"The problem is when it spreads into communities that don't have high vaccination rates," explained Dr. Catherine Troisi, an infectious disease epidemiologist at UTHealth Houston.

"So it depends on where the infected person goes to spread measles to see how far and how many other cases will result," she added.

Measles is a highly contagious virus that is transmitted by the airborne route and can remain in the air or on surfaces for up to two hours after an infected person has left the premises.

It also has a fairly long incubation period, making contact tracing and identification of exposures very difficult, according to Troisi.

In Texas, 29 patients have been hospitalized, six more than previously reported. Cases have been identified in nine counties.

The majority of cases, 156, are in Gaines County, where the outbreak was first identified.

Although most of the cases were in patients who had not been vaccinated or had unknown vaccination status, five cases were found in people who said they had been vaccinated with at least one dose.

Last month, Texas announced the first death of the outbreak in a school-age child who had not been vaccinated and had no accompanying illnesses.

U.S. Centers for Disease Control and Prevention officials have been on the ground in Texas since last week.

"They're advising our doctors and epidemiologists," explained Catherine Wells, Lubbock's director of public health.

"As this process progresses, it's getting to really interesting scenarios about whether or not someone is at risk. So they're helping us get a handle on that," she added.

Lea County is at the center of the outbreak in New Mexico, where 32 cases have been reported.

Last week, New Mexico health officials said they were investigating the cause of death of an unvaccinated person who tested positive for measles. The Lea County resident did not seek health care.

Texas and New Mexico are expected to update again on March 14.

With the latest data, measles cases for 2025 are now approaching last year's total of 285 cases in the United States.

"This is a virus that is sure to spread by mid-May. So we have a few more months. We're certainly going to massively exceed last year's levels," said Dr. Paul Offit, director of the Vaccine Training Center at the Children's Hospital of Philadelphia. | BGNES