Parasitic infections are diseases caused by organisms that live off of another living thing. They can cause fever, fatigue, intestinal symptoms, skin rashes or neurological symptoms. You can get them from contaminated food, water or surfaces, bug bites and eating undercooked meat. Antiparasitic medications treat parasitic infections.
Parasitic infections are any illnesses or conditions caused by parasites living and reproducing in your body. Parasites are organisms that need another living thing (a host) to get the nutrients they need to survive.
Parasitic infections often cause intestinal illness, with symptoms like diarrhea and vomiting. But they can also give you itchy skin rashes or infect other parts of your body, like your brain or lungs.
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There are three main types of parasites that cause infections in humans:
Protozoa are single-celled parasites. They can infect your blood, intestinal tract (gut), brain, skin, eyes and other parts of your body.
Helminth is a general term for parasitic worms. Scientists further classify them as flukes (trematodes), tapeworms (cestodes), roundworms (nematodes) and thorny-headed worms (acanthocephalans). Both adults and immature (larval) helminths can infect you. Helminths usually infect your intestinal tract, but they can also infect your skin, brain and other tissues.
Ectoparasites are insects and arachnids (spider-like bugs) that burrow into your skin and live there. This includes ticks, mites, lice and fleas. They usually don’t infect other parts of your body.
Millions of people around the world get parasitic infections every year. The most common parasitic infections include:
Other examples of parasitic infections include:
Symptoms of parasitic infections depend on where in your body you’re infected. Some common symptoms include:
Depending on where you’re infected, you might have:
Sometimes parasitic infections don’t cause any symptoms.
You can get parasitic infections from:
Some parasitic infections can pass from a pregnant person to the fetus.
Some parasitic infections, like pinworms, are common all over the world. Many other parasitic infections are more common in rural areas of the world without developed sanitation systems. People who are at higher risk for parasitic infections include:
Providers diagnose parasitic infections by looking for parasites or signs of parasites (like their eggs) in body fluids or tissues. To test you for parasites, a provider might take samples of your:
Symptoms of parasitic infections can be similar to many other infectious diseases. The only way to know for sure if you have a parasitic infection is to have a provider evaluate you.
Providers use different medications to treat various types of parasitic infections, including:
Sometimes you might need a combination of different medications to cure the infection. Your provider will select a treatment that’s best for the specific type of parasitic infection you have.
Most parasites will only go away with medication or a combination of medications. Providers treat some skin infections, lice and mites with medicated lotions or shampoos.
Following a few precautions can reduce your risk of parasitic infections, including:
What you can expect with a parasitic infection depends on:
Some parasitic infections respond well to medications. But some infections can last for a long time or keep coming back. Ask your healthcare provider what to expect in your specific situation.
See your healthcare provider if you have symptoms of a parasitic infection. Let them know if you recently:
Go to the emergency room if you experience any of these symptoms of severe illness:
It might be helpful to ask your healthcare provider:
A note from Cleveland Clinic
Parasitic infections affect millions of people around the world. Some people show no signs of these infections, while others develop life-threatening symptoms. Providers can cure most parasitic infections with medication. You can also take precautions to protect yourself against infections, especially when you’re traveling. If you have symptoms of a parasitic infection, talk to a healthcare provider. They can tell you about treatment options and answer any concerns you have.
Last reviewed by a Cleveland Clinic medical professional on 04/07/2023.
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