infections
Overview of Parasitic Infections
Transmission of Parasites
Parasites usually enter the body through the Mouth Skin Parasites that enter through the mouth are swallowed and can remain in the intestine or burrow through the intestinal wall and invade other organs. Often parasites enter the mouth through Fecal-oral transmission of parasites . Some parasites can enter directly through the skin. Others are transmitted by insect bites. Rarely, parasites are spread through blood transfusions, in transplanted organs, through injections with a needle previously used by an infected person, or from a pregnant woman to her fetus. Some other infectious organisms, such as certain viruses and bacteria, also are transmitted by these same methods. Fecal-oral transmission is a common way to acquire a parasite. Fecal refers to feces or stool, and oral refers to the mouth, including things taken into the mouth. Infection that is spread through the fecal-oral route is acquired when a person somehow ingests something that is contaminated by feces from an infected person or animal, such as a dog or cat. Many parasites invade or live in people's digestive tract. Thus, parasites or their eggs are often present in people's feces. Infected people often spread their infection when they do not wash their hands adequately after using the toilet. Because their hands are contaminated, anything they touch afterward may be contaminated with parasites (or with bacteria or viruses that cause digestive tract disorders). If people with contaminated hands touch food—in restaurants, grocery stores, or homes—the food may become contaminated. Then, anyone who eats that food may get the infection. Ingestion does not have to involve food. For example, if a person with contaminated hands touches an object, such as a restroom door, the door can become contaminated. Other people who touch the contaminated door and then touch their finger to their mouth can be infected through the fecal-oral route. Other ways infection can be spread through the fecal-oral route include Drinking water contaminated with raw sewage (in areas with poor sanitation) Eating raw shellfish (such as oysters and clams) that have been cultivated in contaminated water Eating raw fruits or vegetables washed in contaminated water Engaging in sexual activity that involves mouth-to-anus contact Swimming in pools that have not been adequately disinfected or in lakes or parts of the ocean that are contaminated with sewage Some parasites live inside the body and enter through the skin. They may Bore directly through the skin Be introduced by the bite of an infected insect Some parasites, such as Hookworm Infection , enter through skin on the soles of the feet when a person walks barefoot on contaminated soil. Others, such as Insects that carry and transmit organisms that cause disease are called vectors. Some insect vectors transmit parasites called protozoa (such as those that cause Malaria ) and some helminths (such as those that cause Insects (for example, Lice Infestation ) and 