Measles outbreaks across North America have surpassed 2,500 confirmed cases, with transmission accelerating in the United States, Canada, and Mexico. Health authorities on both sides of the U.S. border are racing to contain the spread of a highly contagious virus that has already claimed four lives across the continent.
The U.S. Centers for Disease Control and Prevention confirmed 884 measles cases in 2025 through April, a threefold increase from last year. The vast majority-663 cases-originated in West Texas, where low vaccination rates in tight-knit Mennonite communities have fueled rapid transmission. Genetic testing has linked these cases to parallel outbreaks in Chihuahua, Mexico, and Ontario, Canada.
"El Paso now has the highest measles case count in the state outside of West Texas," said Dr. Hector Ocaranza, the city's top public health official, noting 38 cases in El Paso and 14 across the border in Ciudad Juárez. "Diseases know no borders."
Chihuahua health officials have recorded 786 confirmed infections since February. Mexico's first case was traced to a Mennonite child who traveled to Texas and later fell ill. "This virus was imported, traveling country to country," said Leticia Ruíz, Chihuahua's director of disease control.
The outbreak in Canada's Ontario province has reached 1,020 cases as of this week. Six of ten Canadian provinces have reported infections. Michigan health officials have confirmed nine cases, including four in Montcalm County tied to the Ontario outbreak.
Other U.S. states battling active outbreaks-defined as three or more linked cases-include Indiana, Kansas, Michigan, Montana, Ohio, Pennsylvania, and Tennessee. Indiana's Allen County has reported eight cases, five of them unvaccinated minors. Kansas, with 46 cases, has traced its first infections to the Texas cluster.
Texas reported two child deaths, both in unvaccinated patients with no underlying health conditions. A third fatality occurred in an unvaccinated adult in New Mexico. "Measles pulmonary failure" was cited as the cause of death in one case, according to state health officials.
In total, the CDC has identified cases in at least 30 states, from California to Florida, including Alaska, Vermont, and New York. Each U.S. measles response costs an estimated $30,000 to $50,000, said Dr. David Sugerman of the CDC.
The Pan American Health Organization warned last month that the Americas face a "high" risk of regional measles spread. Dr. Jarbas Barbosa, PAHO director, noted many countries in the region have fallen below the 95% vaccination threshold required to prevent outbreaks.
"If we think about measles as a forest fire, we've got these burning embers that are floating in the air right now," said Dr. Natasha Bagdasarian, Michigan's chief medical executive. "Whether those embers result in another wildfire just depends on where they land."
Chatham-Kent Public Health in Ontario announced public exposure from an Easter Sunday gathering at a Mennonite church. In Ciudad Juárez, Rogelio Covarrubias of the local health department warned: "With a possible case of measles without taking precautions, many, many people could be infected."
