A rare condition that can cause paralysis has sickened two dozen people in a small area straddling the Arizona-Mexico border, authorities said on Tuesday.
The Arizona Department of Health Services reported a cluster of 24 cases of the rare Guillain-Barre Syndrome in Yuma County in far western Arizona and neighboring San Luis Rio Colorado, in Mexico's northern Sonora state.
The rare condition, which normally affects only one in 100,000 people, causes muscle weakness and a creeping numbness in the arms and legs, leading in some cases to paralysis, respiratory problems and even death.
"It's very unusual ... With 24 cases in a small geographic area, that was really concerning to us," Joli Weiss, Arizona's food and water borne epidemiologist, told Reuters.
Of the two dozen cases so far reported, 17 were diagnosed in Mexico, and seven in Arizona.
Weiss said Arizona health authorities were working closely with Mexican federal and state counterparts in Sonora to find the cause of the outbreak, which is usually linked to a bacterial infection in food or water.
"We want to make sure that, if it is a water or food-borne contamination, that we are able to control that and prevent it from occurring in other people," Weiss said.
"We are definitely looking at travel histories for these individuals, as well as what foods they have been (eating and if) they have they been to any large gatherings with any commonalities," she said.
The Arizona health department said the joint investigation into the cluster of cases was the first involving travel across the border by U.S. and Mexican health officials.
Health officials from Sonora have conducted outreach and education to residents in the San Luis Rio Colorado area. Arizona health officials have asked doctors and hospitals to watch for the signs of Guillain-Barre Syndrome and quickly contact their local health office with any possible cases.
Weiss said the condition is not passed from person to person. She recommended people living in or traveling to the region should wash their hands thoroughly after using the bathroom, as well as before cooking and eating.
"This sounds like it's an underlying food-borne or water-borne illness, and those are pretty easily prevented just by taking some of these measures," she said.