The Centers for Disease Control and Prevention (CDC) is warning that more than 200 U.S. patients may be at risk for fungal meningitis after undergoing surgical procedures at clinics in a Mexican border city.

The CDC said Wednesday it is working with the Mexican Ministry of Health and local and state officials to respond to an outbreak linked to patients who underwent procedures under epidural anesthesia in Matamoros, Mexico, across the border from Brownsville, Texas.

The CDC issued a travel advisory last week, warning of the outbreak and telling U.S. patients to cancel any scheduled procedures. In the memo, the CDC said it had identified five Texans who were suspected to have developed cases of fungal meningitis linked to the outbreak, including one who died. 

A second person with a suspected case of meningitis linked to the outbreak has died, the CDC said Wednesday. 

The CDC and Mexican officials identified two clinics in Mexico linked to the outbreak — River Side Surgical Center and Clinica K-3, shutting down both earlier this month. The CDC said officials were still investigating to determine whether other clinics were linked to this outbreak, one in which officials do not know which organism is causing it.

Mexican officials sent the CDC a list of more than 200 U.S. patients who might be at risk based on surgical records.

The CDC is warning patients who had epidural anesthesia at either of the two identified Mexican clinics since January to seek urgent care, even if they do not have current symptoms. Symptoms include fever, headache, stiff neck, nausea, vomiting, sensitivity to light, and confusion.