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Could You Be Infected With Parasites?

Updated: Feb 29


Does the thought of creepy crawly parasites living within your body give you the heebie-jeebies?? Well from my clinical experience, they are more common than we are lead to believe. They are not just a problem of under-developed countries, but are present in many Western nations and can cause a vast range of diseases and symptoms.


What are parasites?

Parasites are organisms that use a host to survive. They use the host's resources to grow and multiply, often at the expense of the host. Though some parasites can be beneficial to the host.


They are incredibly varied, with 3 main types:

1. Protozoa - These are single celled, microscopic organisms that can live within a host or survive on their own (free-living). Once in a host, they can multiply, increasing the risk of serious infection. An example of a parasitic protozoa is Plasmodium which causes malaria.

2. Helminths - Helminths are parasitic worms such as roundworms, tapeworms and pinworms. Pinworms (also known as thread worms) are particularly common in children. They can live on their own or can be parasitic. Adult helminths cannot multiply in humans. They can be large enough to be visible to the naked eye, unlike Protozoa.

3. Ectoparasites - Ectoparasites live on the exterior of the host, rather than in. They infect through burrowing into the skin, biting or stinging the host. Ectoparasites include fleas, ticks, lice and mites. Mosquitos could be considered temporary parasites while they are feeding on the blood of the host. Lyme disease can occur due a tick bite.

The protozoan parasite Giardia
The protozoan parasite Giardia

How are parasites contracted?

Most parasites or their eggs are ingested through contaminated food or water. Transmission can also occur through mosquito or insect bites, direct contact with infected pets and animals, blood transfusions, or bathing in contaminated water. Some can even enter through our skin and through our feet from contact with the ground.


A parasite can reside anywhere in the body (even the brain) but as a cause of poor gut or intestinal function this is mostly due to fecal (poo) particles passing from one person to the mouth of another person (fecal-oral route of transmission).


What are some signs and symptoms of a parasitic infection?

A parasite has the ability to wreak havoc on the human body. However, the severity appears to depend on the type of parasite, size, plus the number present and location within the body.


Intestinal parasites can cause:

  • Gastrointestinal upset - this could include frequent diarrhea, constipation or a mixture of both; bloating, excessive flatulence and gas, gastritis and abdominal pain, cramps and discomfort. Essentially the symptoms of irritable bowel syndrome.

  • Increased appetite, weight loss, or both can occur. Complaints of never feeling full after a meal is a possible sign of a parasitic infection.

  • Nausea or vomiting.

  • Itchiness or a rash around the anus.

  • Fatigue and exhaustion.

  • Iron deficiency anemia.

  • Aches and pains.

  • Restlessness, irritability, insomnia or difficulty sleeping.

  • Teeth grinding at night. (Also known as bruxism).

  • Skin irritations or unexplained rashes, eczema, hives or rosacea.

  • Low mood or anxious feelings.

Acute manifestations at the time of infection typically involve diarrhea, with or without mucus or blood, fever, nausea and abdominal pain. However, the person may also not have any noticeable symptoms, and the infection can go undetected.

If untreated, the parasite can damage the intestinal lining, causing increased intestinal permeability (leaky gut), malabsorption and nutritional deficiencies, chronic fatigue, allergic reactions, gastritis, indigestion, joint pain, decreased immune health, irregular bowel movements and irritable bowel symptoms.


Of note: Elevated levels of oesinophils and basophils from a Complete Blood Count (CBC) blood test can be a indicator of intestinal parasites.

Signs and symptoms of a parasitic infection

Parasites that impact the skin, may cause:

  • Rashes and skin irritations.

  • Itchy skin.

  • Dry, flaky, peeling skin.

  • Crawling sensation under the skin.

  • Irritability and restlessness.

  • Swelling and inflammation.

Blood parasites can trigger:

  • Flu-like symptoms such as a fever, chills, aches and pains.

  • Vomiting and diarrhea.

  • Anemia

  • Fatigue and exhaustion.

Organ failure and death can occur in rare circumstances.

What are some common parasite triggered diseases in the Western world?

Giardiasis - Giardia is a tiny parasite that causes the diarrheal disease giardiasis. Giardia is found on surfaces or in soil, food, or water that has been contaminated with feces from infected people or animals.

Head lice - Head lice live on hair and feed by sucking blood from the scalp. They are common in children and can cause an itchy scalp, neck and ears, and small red bumps.

Pinworm (threadworm) - Common in children, these parasites are spread by eating the eggs of the worm, usually from contaminated feces (poo) under the nails of the child. An itchy anus, irritability and restlessness, particularly at night is common. Weight loss and urinary tract infections are rarer symptoms.

Cryptosporidiosis - Cryptosporidium is a microscopic parasite that causes the diarrheal disease cryptosporidiosis. Although it can be spread in various ways, water (drinking water and recreational water) is the most common route of transmission.

Cyclosporiasis - This intestinal illness is caused by the microscopic parasite Cyclospora cayetanensis. People can become infected with Cyclospora by consuming food or water contaminated with the parasite. People living or traveling in countries where cyclosporiasis is endemic may be at increased risk for infection.

Trichomoniasis - is a sexually transmitted disease (STD) caused by the Trichomonas vaginalis protozoan parasite.

Toxoplasmosis - this disease is by a parasite Toxoplasma gondii found in undercooked pork and infected cat feces. Symptoms can be mild and flu-like. It is thought it could be a trigger for autoimmune thyroid disease in some people.

Lyme disease - A tick-borne disease caused by bacteria Borrelia burgdoferi. A flat, circular rash may be noticed when bitten, or it may go undetected. Symptoms may include a fever, headache, muscle aches, joint pain and fatigue. Chronic symptoms can last months or years, and can involve mobility issues, psychological and cognitive difficulties.

Scabies - An intensely itchy rash caused by a mite known as Sarcoptes scabiei.

What increases the risk of parasitic infection?

  • Poor hygiene.

  • Frequent exposure to pets, animals and children.

  • Working in an institutional setting (e.g. child or elderly care).

  • Dining out often.

  • Consuming raw fish (e.g. sashimi) or poorly cooked meat.

  • Travel to tropical and subtropical climates, and under-developed countries.

  • Poor gut function - such as low stomach/gastric acid levels and low levels of secretory IgA (sIgA) in the mucosal lining of the gastrointestinal tract.

  • A break-down in the skin barrier.

  • A compromised immune system.


parasitic infection risk factors

How can you reduce the risk of a parasitic infection?

  • Wash fresh produce well before consuming.

  • Eat properly cooked fish and meat. Freezing meat can kill many parasites. Defrost and cook before consuming.

  • Wash hands thoroughly after using the toilet, before eating, after touching animals, handling soil or changing nappies and soiled underwear.

  • Keep finger nails short.

  • When travelling to tropical or undeveloped countries, be cautious of where you eat, avoid tap water, increase hand washing or sanitization, and use mosquito nets and insect repellent (preferably one without toxic DEET).

  • Avoid drinking from streams, fountains and lakes without boiling the water adequately first.

  • Avoid bathing in freshwater lakes and streams.

  • Use gloves when gardening or handling soil.

  • Follow safe sexual practices to avoid transmission of parasitic STDs like Trichomoniasis.

  • Avoid medications that reduce stomach acid levels such as Losec or Omeprazole or anti-acids. Stomach (gastric) acid helps to kill unwanted microbes such as parasites on their way through to the intestines.

  • Address poor gut health and nutritional deficiencies. Low levels of zinc and B vitamins can also be a cause of low stomach acid levels, along with a Helicobacter Pylori infection.

  • Improve your immune health by making sure you get adequate sleep, avoid sugar, eat nutritious food & reduce stress.


travelling couple with gastro upset

How do you know if you have a parasitic infection?


Conventional parasitic testing involves:

  • Stool (fecal) tests - a stool sample is sent to a lab for a medical technologist to view under a microscope, looking for a live parasite or eggs.

  • Perianal swab - swab around the anus, then viewed under a microscope.

  • Blood tests - looking for antibodies to specific parasites or a blood smear viewed under a microscope.

  • Endoscopy or Colonoscopy - to view the gastrointestinal tract with a scope (camera).

  • Imaging - such as a CT or MRI to assess organs such as the brain.

Diagnosis can be made challenging by the fact that:

  • Significant symptoms can take many months or years to develop in some cases.

  • Some parasites can "hide" and/or evade the body's immune system.

  • Parasites can go from being dormant and inactive to alive depending on which life cycle phase they are in. If the blood or stool sample is only assessed using microscopy looking for a live parasite or eggs, misdiagnosis can occur.

Polymerase Chain Reaction (PCR) technology to amplify the DNA of the parasite (if there is one) can reduce false negatives, as the parasite can actually be detected even if dead or in it's dormant phase. However, not all labs use this technology and detection is also dependent on the quality of the lab's "genetic library" of parasites.


Detection using PCR technology is very sensitive and even very low levels of parasites can be detected, so before intervention is considered, the patient's complete medical history and presentation needs to be taken into account.

  • The parasite may not even be contained within the small sample of stool. This is why 3 samples over 3 separate days is the gold standard for assessing intestinal parasites. This does not always occur in the conventional medical setting.

GI360 by Doctor's Data in the US is one of my favourite stool tests for assessing parasites. This comprehensive stool test with parasitology, uses PCR technology and microscopy, plus 3 separate samples are taken over a minimum of 3 days and a maximum of 7. A microbiome assessment, plus detection of pathogenic bacteria and viruses is included, along with inflammatory markers and other intestinal health markers.

How do you treat a parasitic infection?

Antibiotics and anti-parasitic medications (prescription & non-prescription) are often used.


Natural, herbal anti-parasitics are an alternative.

These usually contain one or more of the following:

  • Wormwood

  • Berberine

  • Garlic

  • Oregano

  • Black walnut

  • Clove

  • Grapefruit seed extract

Mimosa Pudica seed is also sometimes used to pull out unwanted toxins and parasites.


Care needs to be taken with any parasitic cleanse to avoid a die-off reaction where symptoms can increase. Working with a qualified practitioner is therefore highly recommended.


Since diagnosis can be challenging and it can take many months to years for more obvious symptoms to appear, many parasitic infections can go undetected and untreated, wreaking havoc on the body.

Many are surprised to find their chronic health complaints disappear once a parasitic infection is addressed safely and effectively. For anyone with chronic digestive complaints, a thorough investigation to assess if a parasitic infection is an underlying cause should be a priority.


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