The Mefloquine Controversy A parasite, by definition, takes without giving. Parasitic infections are caused by organisms that range from microscopic single-celled critters to worms a foot or more in length. Parasitic diseases are present all over the world and affect at least 40 percent of the world's population. Unfortunately, these are many of the same areas that divers travel to. Infection with a parasite can result in symptoms ranging from mild skin itch to liver failure, blindness and, in some cases, death.
Parasites can cause infection in several ways.
Some, like malaria and sleeping sickness, are transmitted by insect bites. Other parasites cause infection when their eggs or larvae are eaten, including tapeworms, liver flukes and whipworm. Finally, some parasites actually penetrate the skin upon direct contact. Even though most parasitic infections are curable, it's best not to get infected in the first place. While there are no absolute guarantees, there are several measures that can help reduce the risk of getting sick.