What You Need to Know about Parasites

Let's talk parasites. Yes, parasites! You’ve heard about them, you’ve seen the parasite cleanse hype, and maybe you’ve even wondered if you should “kill them all.” As someone who’s been part of the natural health world and has kids who love animals and the outdoors, I get it—it sounds scary! But here’s the truth: everyone carries some level of parasitic load, and eliminating every single one isn’t a solution.

Just like with the balance of good and bad bacteria in your gut, the goal isn’t total destruction—it’s balance. Not all parasites are harmful, and managing that balance is key to supporting your overall wellness. Curious? Keep reading!

Types of Parasites

Parasites are not diseases, but they can spread diseases, some of which can be fatal. In addition, different parasites affect the human body differently.

Most parasites reside inside their hosts and eat the internal tissues (gonads and digestive glands), but some are nonpathogenic. Nonpathogenic parasites use their hosts as shelters and feed outside the hosts, such as the food the host eats, making them harmless, even in people with weak immune systems (1).

Let’s discuss the three main parasites that affect humans– protozoa, helminths, and ectoparasites.

Protozoa

Protozoa are tiny, single-celled organisms that thrive in many environments around the world. With over 50,000 species, they can live freely or as parasites, and most animals—including humans—carry at least one species of protozoa at some point in their lives.

How do they get in the body?

• Food and water contaminated with the Cysts (dormat forms) and Oocysts (spore-like forms)

• From someone else's bodily fluids or feces

• Skin penetration by larvae (barefeet on contaminated soil)

• Insect Bites

Interestingly, research suggests that almost all of us have protozoa living on or in our bodies at various times. While some species are harmless, others can cause illness. Some of the protozoan diseases include malaria, trypanosomiasis, leishmaniasis, toxoplasmosis, and cryptosporidiosis. (2) Infections caused by protozoa can range from mild to severe, sometimes even becoming invasive.

General signs of a protozoa infection include:

• Diarrhea (may be chronic or acute)

• Abdominal pain or discomfort

• Nausea and vomiting

• Fatigue and weakness

• Weight loss

• Fever and dehydration

Specific Signs by Protazoa Types:

Entamoeba histolytica: Amebiasis

• Chronic diarrhea or dysentery (bloody diarrhea)

• Abdominal cramping and pain

• Flatulence, weight loss

• Fever (in more severe cases)

• Liver abscess (pain in the upper right abdomen, fever, jaundice)

Giardia lamblia: Giardiasis

• Watery, foul-smelling diarrhea

• Bloating and gas

• Greasy stools that float

• Nausea and fatigue

Plasmodium species: Malaria

• Fever and chills (often in cycles)

• Headache and muscle aches

• Fatigue and sweating

• Nausea and vomiting

Toxoplasma gondii: Toxoplasmosis

• Flu-like symptoms (fever, muscle aches, fatigue)

• Swollen lymph nodes

• Eye pain or blurred vision (in ocular toxoplasmosis)

• In severe cases, complications in immunocompromised individuals or congenital infection

Cryptosporidium: Cryptosporidiosis

• Watery diarrhea

• Stomach cramps or pain

• Fever, nausea, vomiting

• Weight loss

Leishmania species: Leishmaniasis

• Skin sores (cutaneous leishmaniasis)

• Fever, weight loss, and enlarged spleen or liver (visceral leishmaniasis)

Helminths

Helminths are worms with elongated, flat, or round bodies, with over 100,000 species.

The main types are roundworms, tapeworms, and flukes. Helminths typically enter the body through contaminated food, water, or soil, or through direct skin contact with contaminated surfaces. Once inside the body, they often reside in the intestines, though some can migrate to other organs, such as the lungs, liver, or bloodstream.

How do they get in the body?

• Ingesting food or water that have their eggs or larvae

• Skin penetration by larvae (barefeet on contaminated soil)

• Insect Bites

These parasitic infections affect over a billion people worldwide, and cause diseases such as enterobiasis, ascariasis, taeniasis, cysticercosis, and schistosomiasis (3). Heavy untreated parasitic infections can cause various health problems from abdominal pain to physical and cognitive growth decline (4).

General signs of helminth infections

• Abdominal pain

• Diarrhea or constipation

• Nausea and vomiting

• Fatigue and weakness

• Weight loss

• Itching or rash (especially around the anus in the case of pinworms)

• Anemia (due to blood loss from certain helminths)

• Malnutrition (as parasites absorb nutrients)

Specific symptoms by helminth type:

Roundworms (Nematodes):

• Abdominal discomfort or pain
• Cough (if the larvae migrate through the lungs)
• Intestinal blockage (in heavy infections).

Enterobius vermicularis (pinworm):

• Intense itching around the anus (especially at night)
• Restlessness and difficulty sleeping

Trichuris trichiura (whipworm):

• Bloody diarrhea
• Rectal prolapse (in severe cases)
• Anemia

Tapeworms (Cestodes):

• Mild abdominal discomfort
• Nausea and diarrhea

• Vitamin B12 deficiency (in Diphyllobothrium infections)

• Cysticercosis (if Taenia solium larvae migrate to muscles or brain, causing seizures or muscle pain)

Flukes (Trematodes):

• Schistosoma species (blood flukes):

• Rash or itchy skin (initial symptom when the larvae penetrate the skin)

• Fever, chills, and cough (early signs after infection)

• Bloody urine (in Schistosoma haematobium)

• Abdominal pain and liver enlargement (in Schistosoma mansoni and Schistosoma japonicum)

Hookworms:

• Itchy rash (often called "ground itch" at the site where larvae penetrate the skin)

• Cough and wheezing (if larvae migrate to the lungs)

• Anemia and fatigue (due to blood loss from feeding adult worms)

• Abdominal pain and diarrhea

Strongyloides stercoralis (threadworm):

• Skin rash at the site of entry

• Cough and wheezing (if larvae migrate through the lungs)

• Abdominal pain and diarrhea

• Chronic infection, particularly in immunocompromised individuals

Ectoparasites

Ectoparasites — tiny organisms that live on the outside of your body — are sometimes more of an itchy annoyance themselves. With over 800 species, common ectoparasites include mosquitoes, ticks, fleas, bedbugs, and lice. These critters spread easily through close contact, often during activities like grooming between people and animals.

However innocent as they may seem, they can still spread diseases and cause a lot of harm.

Some well-known conditions and signs of these pests include:

• Head lice (pediculosis)

• Scabies (red bumps or rash that are really itchy and may have grayish lines between them as “trails”)

• Skin infections like myiasis (from eggs or larvae on an open wound) and cutaneous larva migrans (when hookworms burrow into the skin leaving red, itchy, snake-like trails as they move under the skin)

• Lyme disease - red, circular bullseye rash up to 30 days after tick bite, flu-like symptoms, aching joints – esp the knees, headaches, numbness/tingling in extremities, facial palsy, neck stiffness, memory issues, confusion, irregular heartbeats, dizziness, or shortness of breath.

Pets can also suffer from ectoparasitic infections. They may scratch, bite, or become restless, leading to skin damage, hair loss, and even secondary bacterial infections.

So what can we do about parasites?

Let’s clear something up—when I said not all parasites are harmful, I meant it! By definition, parasites can be harmful to their hosts, but some parasitic infections may actually have protective effects as well. Yes, you read that right!

Take helminths (those parasitic worms), for example. They infect over 1.5 billion people worldwide, and studies have shown that long-term worm infections can reduce symptoms of allergies and irritable bowel disease.(5) Other educational sources suggests that certain parasites, like tapeworms and roundworms, can even order boosts to their host’s immune system. Surprising, right?

Now, while I’ve mentioned that killing every parasite isn’t the goal, let’s be real—some parasites do cause harm, and it’s important to address them. But here’s the good news: when you take steps to reduce the likelihood of infection, you’re already protecting yourself! It’s all about maintaining balance, just like you do with the good and bad bacteria in your gut.

So, what can you do about harmful parasites? The human gut is a complex ecosystem, where the microbiota, immune system, and pathogens all interact to keep things in balance. For example, some studies have found links between gut parasites and certain bacteria, while others highlight how poor hygiene, contaminated food, and unclean water can lead to parasitic infections. (6,7)

Bottom line—when it comes to parasites, balance is key, and with the right habits, you’re already ahead of the game!

Some tips to minimize the risk of parasites are:

• Wash your hands thoroughly after using the bathroom, while preparing food, and when dirty

• Wear shoes when in areas that could be contaminated (high animal traffic/poo)

• Thoroughly cook your meat

• Thoroughly clean your fruits and vegetables

• Keep raw meats and other food separate

• Clean kitchen surfaces -- Try Earthley's All Purpose Spray -- a natural sanitizer

• Avoid food toxins especially in processed foods

• Eat a clean, whole-foods diet

• Drink filtered water – check out What You Need to Know About Water Filters

• Scrape soap under your nails while gardening to avoid dirt buildup.

• Support your gut microbiome – check out The Gut Health Support Guide and Protocol

• Support your immune system – check out The Immunity Tool Guide

• When outside, use a bug deterrent such as Earthley’s Pest Aside and/or wear protective clothing

• Incorporate antiparasitic foods in your diet – coconut oil, garlic, papaya, pineapple, turmeric, ginger, oregano, cloves, and pumpkin seeds

• Occasionally use a parasitic cleanse like Earthley’s Gut Health Oil and Candida Cleanse

Of course, if you have a parasitic infection that is serious or needs treatment, please talk to your trusted natural health care provider!

Disclaimer: This post is not intended as medical advice. These statements have not been evaluated by the FDA, and nothing in this post is intended to diagnose, treat, or cure anything. If you have questions, please do your own research or seek advice from a health professional.