Parasitic Infection Symptoms

Parasitic Infection Symptoms
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There are more than 100 parasites that are able to infect humans. In the United States, millions of Americans are infected each year. Since there are so many parasites, it is important to learn about the more common ones and be able to recognize the parasitic infection symptoms that they can cause.


This parasite is one of the most commonly found parasites in the United States. It is a worm that settles into the host’s colon and can be contracted through unclean clothes, unclean bed sheets, and unclean hands. Patients may experience anal area itching and irritation.


This parasite settles in the host’s intestines. It is found in water or soil and humans contract it by consuming infected vegetables, fruits, and water. Once it is attached to the intestines, it drinks the host’s blood and this worm does have teeth. Patients may experience weakness, nausea, anemia, abdominal pain, and nausea.


This parasite is seen throughout the entire world and is very common. These worms can be as big as a standard pencil. Humans become infected with them when they consume their eggs which can be on vegetables and fruits or in the soil. They initially infect the intestines, but can eventually find their way to the other organs of the body which can result in severe damage. Patients may experience weight loss, infection, weakness, and abdominal pain.


parasitic infection symptoms tapeworm

These parasites are quite rare in humans because for a person to become infected they have to swallow infected fleas. This worm will settle in the intestines and steal essential nutrients from the host and then they will expel dangerous wastes. Some patients experience no symptoms, but when they do occur they can include mineral imbalance, allergies, gas and bloating, sensitivity to touch, dizziness, cloudy thinking, hunger pains, and digestive problems.

Liver Fluke

This parasite attacks the host’s liver and it is a flat worm. Once it is in the liver, it begins making holes in it and causing inflammation. It can live in a human host for about 30 years. It is acquired by consuming contaminated vegetables, undercooked fish, and by swimming in or drinking contaminated water. Patients may experience an enlarged liver, depression, vertigo, cancer, pain affecting the body’s right side, edema, and bile stones.

Protozoa – Giardia Lamblia

parasitic infection symptoms Giardia Lamblia

This is the most common United States parasite, after the pinworm, causing millions of infections each year. It settles in the intestines and is spread through water contaminated with infected fecal matter. It is resistant to chlorine allowing it to survive in tap water and it can be found in natural streams as well. Patients may experience abdominal pain, vitamin deficiency, food sensitivity, and diarrhea.

Protozoa – Entamoeba Histolytica

This parasite causes the disease amebiasis and it is a one-celled organism. It is found in damp environments, water, and soil and can contaminate vegetables and fruits. It is spread through infected fecal matter. Factors that contribute to infection include poor sanitation, crops that use human waste for fertilizer, and unsafe sexual practices. It is the leading cause of protozoa-related death, though most patients do not have any symptoms. When they do experience symptoms they can include abdominal pain, weakness, weight loss, and diarrhea.

Protozoa – Cryptosporidium

This parasite infects the digestive tract and is a single-celled parasite. It can lead to serious gastrointestinal complications and it is acquired when humans come into contact with infected feces and ingest them. It can also be spread through unsafe sexual practices. Patients may experience stomach pain, flu-like symptoms, and diarrhea.

Protozoa – Toxoplasma Gondii

parasitic infection symptoms toxoplasma

This parasite is relatively common and it infects the central nervous system. It is contracted through handling cat litter that is contaminated and consuming undercooked meats. Many people have been exposed to this parasite and because of this they show antibodies. Patients with a compromised immune system are more vulnerable to this protozoa. Most patients do not have any symptoms, but those who do can experience flu-like symptoms, chills, headache, fever, and fatigue.

Other Symptoms

There are other parasitic infection symptoms that patients may experience when they are infected. These can include bowel habit changes, foul-smelling diarrhea, constant hunger while still losing weight, rumbling stomach unrelated to eating or hunger, anxiety, blood in the stool, loss of appetite, memory loss, intestinal obstruction, depression, sore gums and mouth, vomiting, skin rashes, excessive nose picking, shortness of breath, teeth grinding at night, muscle pains and aches, and chronic fatigue.

Diagnosis and Treatment

Analyzing a stool sample or a sample of the patient’s blood are most common. Other tests include a rectal swab and immunoassay.

Antiparasitic drugs are the most common treatment method. Such medications include albendazole, thiabendazole, furazolidone, sulfadiazine, iodoquinol, quinacrine, mebendazole, pyrimethamine, metrodidazole, pyrantel pamoate, niclosamide, and paromomycin. Patients should also have all family members tested, and anyone they live with or spend a lot of time with, and thoroughly clean their home and keep it clean.


Allergy Scape. (2009). Human Parasites. Retrieved on February 2, 2010 from Allergy Scape:

Image Credits

Toxoplasma Gondii: Public Library of Science – Wikimedia Commons

Giardia Lamblia: National Institute of General Medical Sciences – Wikimedia Commons

Tapeworm: Author Unknown – Wikimedia Commons

Pinworm: Sarah J. Wu – Wikimedia Commons