According to Texas health officials, all five victims had recently traveled from Texas to Matamoros to undergo surgeries that involved an epidural, an anesthetic injected directly into the spinal column.

All five developed symptoms within three days to six weeks after their surgeries in Matamoros.

The exact cause of the infections is not yet known, but health authorities said that anyone with a scheduled elective surgery involving epidural anesthesia in Matamoros should “consider canceling or postponing” those procedures.

Meningitis is a potentially fatal infection of the fluid and membranes surrounding the brain and spinal cord that should be treated immediately to prevent serious complications.

Both the CDC and the Texas DSHS warned anyone who had undergone a procedure involving an epidermal in Matamoros since the start of this year to remain vigilant and to seek immediate medical care if they develop headaches, fever or a stiff neck.

Mexico — particularly Mexican border towns — have become popular destinations for U.S. and Canadian citizens seeking cosmetic and other elective surgeries.