Many people are very opposed to keeping giant African land snails as pets, since they are "destructive, invasive, dangerous and illegal." It is true that they have enormous destructive potential and are serious agricultural pests, and they are indeed illegal in the US and some other countries. However, in some other countries they are legal as pets (although in some of these places it is illegal to release them or their eggs into the wild). They are also capable of carrying a parasite that can lead to meningitis, although no cases of this have been seen in the US (and infections with this parasite are usually linked to consumption of snail meat).
In late 2003 and early 2004, several giant African land snails (along with many eggs) were apparently seized in Wisconsin by the United States Department of Agriculture's Animal and Plant Health Inspection Service (APHIS). The Milwaulkee Journal Sential Online (April 29, 2004) reported that APHIS began an investigation after a pet store inquired about the legal status of the giant snails as pets, and as a result APHIS eventually confiscated over 100 snails from pet stores, private owners, and exotic pet swap meets. When several schools discovered the status of these snails, they turned over their snails which were classroom pets and/or projects. All of the snails found so far have been in captivity; none have been discovered in the wild.
What to Do If You Have a Giant African Land Snail
If you have a Giant African land snail, please do not dispose of it yourself and whatever you do, do not release it into the wild. Contact your nearest APHIS office. It is illegal to bring giant African land snails into the US, and doing so can incur hefty fines. While ignorance of the law is generally not a good defense, in this case, officials have not charged anyone and are more concerned about making sure the snails are contained rather than punishing people who kept them. Education about the risks of these snails and controlling the snail population are the most important issues to the USDA right now, and officials have been quoted as saying that anyone who obtained one of these snails while unaware of the laws will not be punished if they notify officials.
How these snails arrived in Wisconsin in the first place has not been determined.
The USDA and APHIS consider these snails dangerous pests and takes its search for giant African land snails very seriously. According to APHIS, in the 1960s a boy smuggled in 3 of the snails into Florida, and these were subsequently released. Within seven years there were an estimated 18,000 of the creatures in the wild and it took 10 years and over a million dollars to eradicate them all. Obviously, the establishment of significant wild populations in the US is a valid concern. Theoretically, because the snail hibernates in cold weather, it could survive and reproduce in most areas of the US.
Giant African land snails are not dangerous in the same sense that pet tigers and alligators might be, but their potential for causing ecological and economic devastation is huge. Assuming, or even hoping, that all owners will be responsible is clearly not enough. If all owners would research and respect the laws about exotic pets like giant African land snails, and never release pets into the wild, then maybe animals like this could be more readily considered good pets.