Correctional Services spokesman Manelisi Wolela has denied allegations that student leader Mcebo Dla.
Experts have rejected as a hoax a chain e-mail warning of deadly spiders lurking in public toilets.
Though not directly attributed to the South African Medical Association (Sama), some of the e-mails are contained on its letterhead.
"This is certainly not something that was issued by us. Someone is using our e-mail stationery to issue these messages," said Sama corporate communications manager Adri van Eeden.
The e-mail alleges that a lawyer died and three women were admitted to hospital after being bitten by the poisonous two-striped telamonia spider.
The women all used a toilet at Olive Garden restaurant in Western Cape, where the spider was said to be hiding "under the [toilet] seat, out of normal view".
The e-mail warned that the spiders could be "anywhere in the country".
However, a directory search revealed that the "Olive Garden" restaurant was not listed anywhere in South Africa.
Ansie Dippenaar, a specialist scientist at the Agricultural Research Council, said the two-striped telamonia spider could not be found in South Africa. "There is no truth to the e-mails, so ladies can sit on toilet seats and enjoy themselves."