Chronic infection with parasites and/or fungi may be involved in all sorts of health issues, such as chronic fatigue, fibromyalgia, and autoimmune disease. Eradicating the pathogens is not easy due to their persistent nature. We have established parasite and fungal treatment protocols that aim to aggressively eliminate these pathogens.
What are Parasites?
Parasites are organisms that live in, or on, a host from which they get their nutrients. Many live in the intestine or vagina of the host while other live in the blood or tissues. Intestinal infections are often caused by ingestion of water or food that has been contaminated by fecal matter. Others may be spread by skin contact with dirt or freshwater. Some are spread by insect vectors such as mosquitos or ticks.
The bulk of parasite infections occur in areas with poor sanitation, such as Asia, Africa, Central and South America. They are much less common in more developed countries. We have quite a few that are endemic in the US, such as Giardia duodenalis, Cryptosporidium and pinworms, all which infect the intestines. Trichomonas vaginalis is a fairly common vaginal infection. Cryptosporidium is a leading cause of waterborne disease among humans in the US, while Giardia is found in nearly every single waterway in the US.
Types of Parasites
The three main types of parasites include single-cell organisms (protozoa and microsporidia), multicellular worms (helminths), and ectoparasites such as fleas, lice, mites, scabies and ticks.
Protozoa are simple single cell organisms that are able to reproduce within their host and as such can cause overwhelming infections. There are tens of thousands of different types of protozoans, which are classified by how they move. Amoeba form temporary pseudopods that resemble feet, ciliates use short hair-like cilia, flagellates use one or more whip-like structures (flagella) while sporozoans such as Plasmodium (malaria) or Babesia aren’t capable of moving on their own.
Common intestinal protozoa include the amoeba Entamoeba hystolytica, the ciliate Balantidium coli, the flagellate Giardia duodenalis, or the sporozoan Cryptosporidium and Cyclosporiasis species. Giardia is really common and we often treat people that have been out enjoying nature hiking, camping or hunting and had contaminated water to drink. Recall in 2018 there was an outbreak of Cyclosporiasis in the US that originated from a packaged vegetable product. Systemic protozoa infections include diseases such as malaria, babesiosis, toxoplasmosis, or sleeping sickness.
Microsporidia are really more closely related to fungi and they live inside the host cells where they reproduce by making spores which then travel through the body causing an inflammatory response. There are about a dozen that infect humans and the route of transmission is mostly ingestion or inhalation. Typically microsporidia is a concern only in immune compromised hosts, although asymptomatic infections likely occur.
Helminths, or worms, are more sophisticated than protozoa as they have multiple cells and complex organ systems. The two main categories of helminths are roundworms and flatworms. Helminths don’t reproduce within the host but they can hang out in the host for a long, long time. Some worms can infect their host for decades and grow to as much as 50 feet long!
Roundworms, or “nematodes”, are cylindrical with an internal body cavity. They inhabit the intestines and are spread by ova or larvae in the feces. Common round worms include Ascaris, Trichuris, Strongyloides and Necator americanus (hookworm). We routinely treat kids with itchy bottoms for Enterobius vermicularis, known as the common pinworm or threadworm.
Flatworms include tapeworms and flukes. Tapeworms, or “cestodes”, are fairly common and mostly obtained by eating infected meat, typically fish, pork or beef. The tapeworm attaches to the gut lining and absorbs nutrients directly from the host. It’s important when treating tapeworms to kill not just the long worm but also the attached head section which may regenerate. Flukes, or “trematodes”, infect the gut, but also the blood, liver or lungs. Common flukes are Schistosoma (blood fluke), Fasciola and Clonorchis (liver/bile flukes), and Paragonimus (lung fluke). Infections with flukes are mostly caused by eating various contaminated foods or water, but some such as Shistosoma can invade through the skin while wading or swimming in contaminated water.
Symptoms of Parasite Infection
Given the many parasites that infect the intestine it’s not surprising that gastrointestinal symptoms are very common, including watery diarrhea or bloody dysentery, abdominal pain, increased appetite or unexplained weight loss. Also, since parasites commonly disrupt the lining of the intestine and consume nutrients, deficiencies of iron, B12 or folate may occur. Beyond this however, it gets complicated as parasites may infect nearly everywhere else in the body, causing a myriad of symptoms including fever, chills, fatigue, weakness, muscle aches, or skin rashes.
Diagnosing Parasite Infections
Most Common Parasite Medications
- Ivermectin (Stromectol) 12 mg 3-4x/day
- Praziquantel (Biltricide) 600 mg 4x/day (or Levamisole 50 mg 4x/day)
- Metronidazole 500mg tid or Tinidazole 500 mg 3 – 4x/day or
- Albendazole (Albenza) 400 mg 2x/day
- Pyrantel pamoate 250 mg 3-4x/day
- Nitazoxanide (Alinia) 500 mg 3x/day
Most Common Fungal Medications
- Diflucan (fluconazole) 200 mg 1x/day
- Diflucan (fluconazole) 200 mg 1x/day + Nystatin capsules 500,000IU 4x/day
- Diflucan (fluconazole) 100 mg 1x/day + Sporanox (itraconazole) 100 mg 1x/day
- Sporanox (itraconazole) 200 mg 1x/day
- Ketaconazole 200 mg 2x/day
Treatment Cycles
Due to parasite resistance to drugs we often use 2-3 anti-parasitic drugs at once. This is followed by anti-fungal treatment. Ideally one starts only one medication at a time for the first round in order to identify any side effects. Depending on which medications are used a metabolic panel and cbc are usually done between cycles. It’s always a good idea to run a drug interaction check as well.
- Treat parasites for 10 – 21 days
- Treat fungus for 7-10 days
- Take a break for a week.
This cycle is performed at least 4 to 6 times, or even longer as indicated.
Treatment Protocols
To cover most classes of parasitic infections, a combination of antiparasitic drugs is often required, as different drugs target different types of parasites (protozoa, helminths, ectoparasites). No single drug is universally effective against all classes of parasites, but several drugs are commonly used in combination to provide broad-spectrum coverage.
Key Classes of Parasites and Corresponding Drugs
Protozoa (e.g., Giardia, Entamoeba, Plasmodium):
- Metronidazole (Flagyl): Effective against Giardia and Entamoeba species (e.g., Entamoeba histolytica).
- Tinidazole: Similar to metronidazole but with fewer side effects and shorter dosing.
- Nitazoxanide: Effective for giardia, Cryptosporidiosis, Amebiasis, Cyclosporiasis, B homonis
- Chloroquine or Artemisinin-based (sweet wormwood) therapies: Used for Plasmodium species that cause malaria.
Nematodes (Roundworms):
- Albendazole or Mebendazole: Broad-spectrum activity against intestinal nematodes (e.g., roundworms, hookworms, whipworms, and pinworms).
- Ivermectin: Effective for strongyloidiasis, onchocerciasis, and other nematode infections, as well as for scabies and lice (ectoparasites).
- Pyrantel pamoate: primarily effective against pinworms, roundworms, and hookworms.
- Nitazoxanide: for roundworms, Fascioliasis or Liver Fluke Infection, Dwarf Tapeworm
Trematodes (Flukes) and Cestodes (Tapeworms):
- Praziquantel: Effective against flukes (e.g., Schistosoma) and cestodes (tapeworms, including Taenia solium which causes neurocysticercosis).
Ectoparasites (Lice, Scabies):
- Ivermectin: As mentioned, also useful for ectoparasitic infestations like lice and scabies.
- Permethrin: Topical treatment for scabies and lice infestations.
Summary of a Broad-Spectrum Approach
A combination of Albendazole, Ivermectin, and Metronidazole, and Praziquantel would cover a wide range of parasites:
- Albendazole: Effective against various helminths (roundworms, hookworms, etc.).
- Ivermectin: Covers nematodes and some ectoparasites.
- Metronidazole: Addresses protozoal infections (like Giardia and Entamoeba).
- Praziquantel: For fluke or tapeworm infections, could be added to the regimen.
A Note on Fenbendazole
Fenbendazole and Metronidazole are both antiparasitic medications but differ significantly in their mechanism of action, spectrum of activity, and clinical use. As Fenbendazole is available over the counter, I find many patients are taking it without medical oversight. So just a note…
Fenbendazole works by inhibiting the formation of microtubules in parasites, thereby interfering with their cellular structure and ability to absorb nutrients, eventually causing death. It is primarily used in veterinary medicine to treat various helminthic (worm) infections in animals (e.g., dogs, cats, livestock). It is effective against gastrointestinal parasites such as roundworms, hookworms, whipworms, and some tapeworms.
Metronidazole works by disrupting the DNA of the microorganisms, leading to the inhibition of nucleic acid synthesis, which results in cell death. It is primarily used in human medicine to treat protozoal infections and anaerobic bacterial infections. It is effective against protozoa like Giardia lamblia and Entamoeba histolytica, and also treats bacterial infections like Clostridium difficile colitis and bacterial vaginosis.
Limitations
This combination does not cover all parasitic infections and may require additional or alternative therapies depending on specific parasites, drug resistance patterns, or co-infections.
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