Measles Outbreak Spreads from Texas to Mexico, Forcing School Closure After Child's Visit to Seminole

A 9-year-old boy from Cuauhtemoc, Mexico contracted measles during a January 2025 visit to Seminole, Texas, triggering an outbreak that spread to all 32 Mexican states and infected over 17,000 people by May 2026, killing at least 40. The outbreak originated in a Mennonite community where vaccination rates were low and some residents actively refused immunization, then spread through Indigenous farmworkers to the broader population. Genetic testing linked the cases to a Canadian virus strain that appeared in Texas, where over 760 infections occurred in Seminole alone. Mexico's vaccination rate had fallen below 80% by 2023 amid health spending cuts and system restructuring, with only two-thirds of 1-year-olds in Chihuahua receiving their first measles shot in 2024, well below the 95% coverage needed to prevent spread.

Cross-border measles transmission

• ▪Measles was declared eliminated in both Mexico and the United States more than a quarter-century before May 17, 2026
• ▪Mexican authorities conducted genetic tests on more than 100 measles cases in Chihuahua that matched the genotype D8 and lineage MVs/Ontario.CAN/47.24 virus that appeared in Canada in 2024 and later in Texas
• ▪A 9-year-old boy from Cuauhtemoc, Mexico visited relatives in Seminole, Texas in January 2025 and developed measles after returning home
• ▪More than 760 people in Seminole, Texas were infected with measles in the months following January 2025, with 99 hospitalized and two girls dying
• ▪Dr. Miguel Nakamura, director of epidemiological information at Mexico's Health Ministry, stated that the measles outbreak in all of Mexico's 32 states originated from the outbreak in Chihuahua

Vaccine coverage decline in Mexico

• ▪A study in the science journal Vaccines found a 25% deficit in Mexico's administration of measles vaccines between 2006 and 2024
• ▪More than 17,000 measles infections were confirmed in Mexico between the start of 2025 and May 17, 2026, four times the number in the United States
• ▪At least 40 Mexicans died of measles complications between the start of 2025 and May 17, 2026, ranging from babies to middle-age farmworkers
• ▪In the Chihuahua region, only around two-thirds of 1-year-olds had received their recommended first measles shot in 2024
• ▪Mexico's measles vaccination rate fell below 80% by 2023 according to a study in the science journal Vaccines
• ▪At least 95% of a community needs to be vaccinated with two doses of the MMR vaccine to avoid measles spread, according to the World Health Organization

Mennonite community outbreak dynamics

• ▪Iris Ramírez, a state epidemiological official in Chihuahua city, observed in late March 2025 that store clerks were contracting measles after Mennonites from Cuauhtemoc traveled to shop at Costco and Sam's Club on weekends
• ▪The Esperanza Mennonite school in Cuauhtemoc has 240 students from kindergarten through high school and suspended classes after one-third of the student body became sick with measles
• ▪Artemio Bergen, a student at the Esperanza Mennonite school, spent a week in the hospital with measles in February 2025 and recovered on February 20, 2025

Indigenous farmworker deaths

• ▪By the end of 2025, the measles epidemic in Chihuahua state had killed 21 people, 17 of whom were Indigenous
• ▪A 4-year-old girl, the daughter of an Indigenous laborer in a Mennonite neighborhood, died of measles in Cuauhtemoc in early June 2025
• ▪The first person to die in Cuauhtemoc's measles outbreak was a 46-year-old Indigenous farmworker in early June 2025

Anti-vaccine sentiment in Texas

• ▪About 77% of kindergarteners in Gaines County, Texas were reported to have received the measles shot for the 2024-25 school year

Mexican health system deterioration

• ▪Chihuahua state confirmed around 4,500 measles cases by the end of 2025, more than in the entire United States
• ▪A measles pandemic in Mexico in 1989-90 left more than 8,000 dead