According to information published by UDSA APHIS Michigan Office
"The human health risk associated with handling the giant African land snails is low in the U.S. This type of snail is one of many types that can be infected with a parasite that can cause meningitis, but it is unknown if any of these snails in the continental U.S. are infected. The only way snails can become infected is by eating infected rat stool. The likelihood a snail is infected is considered lower if the snail was bred indoors and kept in a tank than if it was collected from the outdoors or ever been outdoors.
Even if the snail is infected, the infection can spread to humans only under unusual circumstances. People may become infected by eating raw or undercooked snails or slugs that contain a parasite. Whether the slime shed by infected snails can contain parasite larvae and infect people is unknown. All snails, even those that are legal to possess, can carry salmonella and other bacteria."