June 23, 2023 | A parasite is an organism that lives on or in a host organism and gets its food from or at the expense of its host. Parasites may be present in food or in water and can be identified as causes of foodborne or waterborne illness in the United States. They range in size, from tiny single-celled organisms to worms visible to the naked eye. Their lifecycle may also vary. They may be transmitted from animals to humans, from humans to humans, or from humans to animals. While some parasites use a permanent host, others go through a series of developmental phases using different animal or human hosts. They may be transmitted from host to host through consumption of contaminated food and water, or by putting anything into your mouth that has touched the feces of an infected person or animal. Infection symptoms vary depending on the type of parasite. The illnesses they can cause range from mild discomfort to debilitating illness and possibly death.

June 23, 2023 | There are three main classes of parasites that can cause disease in humans, protozoa, helminths, and ectoparasites. Protozoa are microscopic, one-celled organisms that can be free-living or parasitic in nature. They are able to multiply in humans, which contributes to their survival and also permits serious infections to develop from just a single organism. Helminths are large, multicellular organisms that are generally visible to the naked eye in their adult stages. Like protozoa, helminths can be either free-living or parasitic in nature. In their adult form, helminths like flatworms or roundworms cannot multiply in humans. Ectoparasites are organisms such as lice and mites that attach or burrow into the skin and remain there for relatively long periods of time, for weeks or even months. Some ectoparasites spend their whole lifecycle on their hosts, but many, for example, fleas and ticks, develop elsewhere and climb onto their hosts in order to feed.

June 23, 2023 | Think you can’t come in contact with a parasite just because you haven’t traveled abroad? More than 60 million people in the U.S. are chronically infected with Toxoplasma gondii, a single-celled, microscopic parasite. Because it reproduces only in cats, wild and domestic felines are the parasite’s ultimate host. Toxoplasmosis may cause flu-like symptoms in some, but most people affected never develop any symptoms. The parasite can be found in cat feces, contaminated kitchen utensils and unwashed fruits and vegetables. And each year 1.1 million Americans are newly infected with trichomonas vaginalis, a protozoan parasite that causes the sexually transmitted disease trichomoniasis. The parasite passes from an infected person to an uninfected person during sex. About 70 percent of infected people do not have any symptoms. When trichomoniasis does cause symptoms, they can range from mild irritation to severe inflammation.

June 23, 2023 | International travelers can be at risk for a variety of infectious and non-infectious diseases. Travelers visiting foreign countries may acquire parasitic illnesses through ingestion of contaminated food or water, by vector-borne transmission or through person-to-person contact. Vectors are living organisms such as mosquitoes, fleas or ticks that can transmit infectious diseases between humans or from animals to humans. Some foods are contaminated by food service workers who practice poor hygiene or who work in unsanitary facilities. Giardia is a parasite found in contaminated water in every country in the world. It can cause chronic diarrhea lasting for several weeks in addition to weight loss, excessive burping and fatigue. International travelers should contact their physicians least four to six weeks before their departure to obtain any needed vaccinations and to receive current health information on the countries they plan to visit.

June 23, 2023 | There’s a difference between infection and disease. Infection occurs when bacteria, viruses or other microbes that cause disease enter your body and begin to multiply. Disease occurs when the cells in your body are damaged, as a result of the infection, and the signs of an illness appear. In response to a parasitic infection, your immune system springs into action. An army of white blood cells, antibodies and other mechanisms goes to work to rid your body of whatever is causing the infection. You can prevent a parasitic infection through simple tactics, such as washing your hands regularly, being careful with food and water and taking appropriate medications. Prevention is especially important as there are no vaccines for parasitic diseases. Some medicines offer short-term protection from particular germs. For example, taking an anti-parasitic medication might keep you from contracting malaria if you travel to or live in a high-risk area.