Parasites You Should Know

They suck your blood. They mate in your liver. Say hello to some guests you don't want to bring home from your next tropical dive vacation.

By Sam Shelanski, M.D.

A parasite, by definition, takes without giving. Bring any relatives to mind? 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. Most parasites are more common in tropical and subtropical parts of the world, and in some regions, 95 percent of the people may be infected with a particular parasite. 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.

How Do I Get Infected?

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. Schistosomiasis - which can cause swimmer's itch, liver failure and bladder cancer - is contracted this way.

How Do I Avoid Getting a Parasite?

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.

• Avoid it. The best weapon against insect-borne diseases is to avoid getting bitten in the first place. Wear long sleeves and pants, and light-colored clothing. Avoid perfumed soaps. Use mosquito netting sprayed with an insecticide, such as Permethrin. Most importantly, use insect repellents. Most of the effective repellents on the market contain deet in concentrations ranging from 30 to 100 percent. Repellents with concentrations of deet higher than 30 percent should not be used on children. For those people who find deet irritating to the skin, Avon's Skin-So-Soft is popular.
• Cook it. The possibility of both bacterial and parasitic contamination of food is reduced if the food is thoroughly cooked. This doesn't mean that you should avoid all local specialties. Just try to partake of such dishes at slightly more upscale restaurants, or at least ones that seem clean. Remember, there are no guarantees. I spent six weeks sick as a dog after getting a parasite from a raw lamb dish in a Lebanese restaurant - in New York City.
• Wash it. Making sure that you wash your hands, and that all fruits and vegetables are washed in clean water, can also help reduce the risk of ingesting parasite eggs and larvae that may be deposited in the soil.
• Outsmart it. Reducing the risk of illness caused by parasites that infect through direct contact requires a little bit of research. The risks vary from region to region. In Fiji, hookworm is common, so it is recommended that you not walk barefoot through dirt areas. Taking some time before the trip to find out what parasites are found in a particular location can let you know what actions to take to avoid infection. Contact the Centers for Disease Control traveler's hotline (404-332-4559) for the most current information for the country you're planning to visit.

What To Do When You've Got One

So, you've recently returned from the dive trip of a lifetime to the tropics, and you get sick. It may be a fever, a cough, an itchy rash, a skin sore or stomach problems. All may be signs of a parasitic infection, even if you returned from your trip several months earlier. Most good doctors will ask about your travel history, but it is sometimes overlooked. In any case, it may be necessary to see a physician who specializes in travel medicine or infectious disease to get an accurate diagnosis and receive the proper treatment for a parasitic disease.

Questions for Dr. Shelanski should be addressed to RSD, Dive Medicine, 6600 Abercorn St., Suite 208, Savannah, GA 31405; e-mail RSDmgzn@aol.com.