State health officials are seeking to confirm the vaccine status of the four self-reported cases, but no mutations of the virus have been recorded.

The number of measles cases linked to an outbreak in West Texas has grown to 58, according to the Texas Department of State Health Services.

At least 58 cases have been confirmed. Health officials — who are scrambling to get a handle on the vaccine-preventable outbreak — suspect 200 to 300 people may be infected.