The Texas health department reported that measles cases in the state increased to 481 from 422 earlier in the week, as the U.S. battles one of the largest outbreaks in the past decade.

Cases in Gaines County, the center of the outbreak that started in late January, rose to 315 from 280 on April 1, the Texas Department of State Health Services said. Hospitalizations rose to 56 from 42.

Separately, the New Mexico Department of Health said the state reported 6 additional measles cases from 3 days ago, taking the total to 54. Most of New Mexico's cases were reported in Lea County, which is adjacent to Gaines County in Texas.

In New Mexico, 36 cases were in people who were not vaccinated, while 471 of the infected in Texas were either unvaccinated or their vaccination status was unknown.

Infectious disease experts had warned last week that low vaccination rates can make the population vulnerable to highly contagious measles and the outbreak could spread further.

Measles cases have been reported in 20 U.S. jurisdictions this year — Alaska, California, Florida, Georgia, Kansas, Kentucky, Maryland, Michigan, Minnesota, New Jersey, New Mexico, New York City, New York State, Ohio, Pennsylvania, Rhode Island, Tennessee, Texas, Vermont, and Washington.