(CNN) -- Contraband alcohol is believed to have sickened at least seven Arizona inmates, who are receiving antitoxins for suspected botulism poisoning, officials said Tuesday.
Pinal County communications director Heather Murphy said inmates began showing symptoms at the Arizona State Prison Complex Eyman in Florence.
Four inmates become seriously ill Saturday. By Monday, seven inmates were in intensive care, all suffering from some form of paralysis, officials said.
"It is suspected that the inmates came in contact with the toxin from homemade prison 'hooch,' made from fermented fruit," said Murphy. An eighth inmate was transported for observation, but Murphy said "his condition has not reached a threshold that the medical team and CDC believe antitoxin should be administered."
The affected pod houses about 15 inmates. Pinal County and state corrections officials were working to isolate and eliminate the source of the suspected botulism.
Samples of the suspected contraband alcohol, often called "pruno," have been sent to the Centers for Disease Control of Prevention for testing. Results may take about a week.
According to the CDC, botulism is "a rare but serious paralytic illness caused by a nerve toxin" and can be fatal. Symptoms can include "double vision, blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth, and muscle weakness" in patients.
Bill Lamoreaux, a spokesman for the state corrections department, said preventative measures will include educating prisoners about the dangers of contraband alcohol and searches to ensure it can't be manufactured or consumed.
CNN's Miriam Falco contributed to this report.