Lea County, New Mexico, is now reporting an outbreak of measles, according to the New Mexico Department of Health (NMDOH). Lea County is near Gaines County, Texas, where measles cases continue to rise as part of the original outbreak.

Texas' measles outbreak is now at 90 cases, the highest yearly case count since 1992. Experts say the number is likely to grow more. Here's why.

A fast-growing measles outbreak in West Texas has nearly doubled in just one week, now totaling 90 cases across seven counties and spreading to New Mexico. Earlier this week, the Texas Department of State Health Services confirmed 49 cases in five counties.