Parasites, Bacteria, and Viruses
Parasites, bacteria, and viruses are often thought of only as causes of infection, but their relationship with cancer is more complex. Some microbes are now recognised as direct or indirect contributors to cancer development, either by causing long-term inflammation, damaging DNA, weakening immune surveillance, or altering the tissue environment in ways that make cancer more likely to arise or progress.
At the same time, the human microbiome also plays a protective role, helping regulate immunity, inflammation, metabolism, and even response to cancer treatment.
What studies show
Global prevalence of intestinal parasites in cancer patients
This systematic review and meta-analysis identified 34 eligible studies on intestinal parasites among cancer patients, covering a total of 4,752 participants. The overall prevalence of intestinal parasites among cancer patients was found to be 28.42%. Patients with solid tumors had the highest prevalence of intestinal parasites at 31.13%…
Viruses and Human Cancers
Study: About a fifth of all human cancers worldwide are caused by infectious agents. In 12% of cancers, seven different viruses have been causally linked to human oncogenesis: Epstein-Barr virus, hepatitis B virus, human papillomavirus, human T-cell lymphotropic virus, hepatitis C virus, Kaposi’s sarcoma herpesvirus, and Merkel cell polyomavirus.
Parasitic infections in immunocompromised patients can lead to serious complications
This study says: Intestinal parasitic infections in immunocompromised patients can lead to serious complications when not diagnosed and treated early. A total of 73 patients aged from 20 to 85 years…participated in the study. Of the patients surveyed, 45 (61.6%) were positive for one or more species of intestinal parasites and/or commensals. Breast cancer showed the highest occurrence (32/43.8%), followed by intestinal (10/13.7%) and stomach (6/8.2%).
Parasites, Bacteria, and Viruses
Certain infectious agents, including viruses, bacteria, and parasites, can cause cancer or increase the risk of developing cancer. Some viruses can disrupt signalling that normally keeps cell growth and proliferation in check. Also, some infections weaken the immune system, making the body less able to fight off other cancer-causing infections.1
This is not a complete list.
| VIRUS | CAUSES |
| Hepatitis B Virus (HBV) Hepatitis C Virus (HCV) | Liver cancer1 |
| Epstein–Barr Virus (EBV) | Some types of lymphoma Nose and throat cancer1 |
| Human Papilloma Virus (HPV) | cervical cancer anal cancers oropharyngeal cancer vaginal cancer vulvar cancer penile cancers1 |
| Human T-Cell Leukemia/Lymphoma Virus Type 1 (HTLV-1) | non-Hodgkin lymphoma (aggressive type)1 |
| Merkel Cell Polyomavirus (MCPyV) | Merkel cell carcinoma (rare type of skin cancer)1 |
| BACTERIA | CAUSES or LINKED TO |
| Helicobacter pylori | gastric cancer (a type of stomach cancer) a type gastric MALT lymphoma (a type of lymphoma in the stomach lining)1 |
| Chlamydia (persistent infections) | cervical carcinoma (especially in patients with the human papillomavirus (HPV) coinfection)2 |
| Salmonella typhi | gallbladder cancer2 |
| Chlamydia pneumoniae | lung cancer2 |
| PARASITES | CAUSES or LINKED TO |
| Schistosoma hematobium (a parasitic flatworm) | Bladder cancer.1 |
| Opisthorchis viverrini | cholangiocarcinoma (cancer of the bile ducts in the liver).1 |
| S. japonicum | colorectal cancer hepatocellular carcinoma (liver cancer) metastatic lung tumors squamous cell carcinoma rectal carcinoid tumor3 |
| schistosomiasis mansoni | prostatic adenocarcinoma sigmoid colonic cancer bladder cancer3 |
| Clonorchis sinensis | cholangiocarcinoma (bile duct cancer)3 |
References:
1. Risk factors: infectious agents [Internet]. Cancer.gov. 2019. Available from: https://www.cancer.gov/about-cancer/causes-prevention/risk/infectious-agents
2. Yusuf K, Sampath V, Umar S. Bacterial Infections and cancer: Exploring this association and its implications for cancer patients. International Journal of Molecular Sciences [Internet]. 2023 Feb 4;24(4):3110. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC9958598/
3. Van Tong H, Brindley PJ, Meyer CG, Velavan TP. Parasite infection, carcinogenesis and human malignancy. EBioMedicine [Internet]. 2016 Dec 1;15:12–23. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC5233816/
Bacterial Biofilms
Biofilms are groups of bacteria held within a protective matrix. Biofilm-forming bacteria are considered to play a significant role in cancer formation. A recent study revealed that biofilms aid in the formation of secondary tumors known as metastases, which occur at other anatomical sites. In addition, bacterial resistance to antibiotics and other drugs can exacerbate issues related to treatment strategies. (study)
An example is Triple Negative Breast Cancer
This 2025 study identified three bacterial species that were consistently and significantly enriched in TNBC tissues:
- Gemmiger formicilis
- Anaerobutyricum soehngenii
- Azospirillum oryzae
The microbes enriched in TNBC were not just bystanders—they were associated with pathways directly linked to cancer hallmarks.
No drugs to target Biofilms
Due to Multi-Drug Resistance, no drugs are capable of targeting these biofilms. The studies on the effect of antibiotic use on breast cancer treatment have suggested more adverse effect than a beneficial one.
Vitamin C may help
(1gram daily for two weeks) may decreased Gemmiger formicilis (study).
Parasites, bacteria, and viruses
– Some Solutions
Artemesinin
Artemisinin is has antimalarial, antiparasitic, anti-fungal, antiretroviral, and anticancer properties. This study involving 23 Colorectal Cancer patients tested the anti- properties of oral artesunate (a derivative of Artemisinin). The survival beyond 2 years in the artesunate group is estimated at 91% whilst surviving the first recurrence in the placebo group is only 57%. See Artemesinin page for more
Oregano Oil
This study says oregano essential oil has the potential to be a powerful antibacterial agent against several strains of Escherichia coli and Staphylococcus aureus. At a concentration of 25%, the oil exhibited substantial antibacterial action, and at concentrations as low as 0.19%, it was able to stop the growth of biofilm.
Para-Free Plus
Para-Free Plus has a triple action: it works against parasites, yeasts, and cleanses the colon!
Available at ournaturalselection.com
Protocol to Kill yeast and pathogens
(based on biochemist and cancer expert Chris Woollam’s protocols)
Do this for a total of 12 consecutive weeks – 6 weeks during treatment and for a further 6 weeks after you finish taking drugs.
1. Take a yeast killer like oregano oil – works providing you have a strict no-sugar, no-lactose, no alcohol diet for 12 weeks.
2. Take a pathogen killer like artemisinin – kills ‘bad’ bacteria such as E coli. The dose is about 80 mg per 10 kg of body weight taken before bed every night for 8 weeks.
Note: Don’t start artemisinin until 3 months after radiotherapy; or if you smoke.
Para Free Plus is excellent at killing off parasites.
Pau d’arco and olive leaf extract can be very helpful in suppressing viruses.
3. Take a good B complex – it neutralises the build-up of homocysteine – a driver of cancer – and cancer patients usually have low levels of folic acid and B-12.
4. Take a good probiotic along with soluble fibre.
5. Take 1 tablespoon Apple Cider Vinegar per day.
Note: You can buy probiotics etc from Chris Woollam’s own supplements range.
Ivermectin
A European Medicines Agency article contains the following: EMA’s human medicines committee (CHMP) has adopted a positive scientific opinion for Ivermectin/Albendazole for the treatment of infections caused by several types of worm parasites including lymphatic filariasis, a neglected tropical disease.
Fenbendazole
An article on fenbendazole.org says: Fenbendazole is a versatile medication frequently prescribed to treat parasitic infections in both animals and humans. It’s categorized under the benzimidazole group of drugs. Its primary function is to disrupt the parasites’ energy-producing processes, causing them to perish.
Mebendazole
This National Library of Medicine article says:
Mebendazole is a typical, broad-spectrum benzimidazole used for more than 40 years in humans to treat various parasitic infestations.
Side-effects
Based on toxicology studies, benzimidazoles such as Fenbendazole, Mebendazole or Albendazole seem to be safe drugs.
However, a drug without any side-effects does not exist. Scientific data reports do not reveal significant adverse reactions from taking fenbendazole. Despite the fact, there are anecdotal reports of potential toxicity:
- Up to 5 % of people can experience stomach discomfort or diarrhea when taking large quantities of fenbendazole with no breaks.
- People with severe liver or kidney failure have lower medication excretion rates, therefore, fenbendazole can accumulate and cause unexpected side-effects. Doses should be divided accordingly in this situation.
- When used in large quantities for a long period of time without breaks, fenbendazole can cause an asymptomatic liver enzyme increase due to the fact of the substance being mainly metabolized in the liver. This is reversible with the help of a couple week pause from the medication.
How can you weaken Epstein-Barr?
Source: canceractive.com
‘With difficulty’, is the honest answer. It is probably more realistic to try to get the virus to become dormant again via boosting your immune system strongly – for example, with Echinacea, Cat’s claw, Astragalus, Grape seed extract, Pine bark extract, Essiac, Turmeric and so on.
Are there any natural antivirals that can help?
* Cordyceps medicinal mushroom – a 2014 study showed that cordycepin reduced EBV viral load and infection rate significantly. A further 2016 study showed that Cordycepin could enhance conventional antitumour chemotherapy in EBV-linked cancers. The mushroom compound must be organic.
* Olive Leaf Extract contains Oleuropein, which is a known antiviral. It also boosts the immune system. It is recommended by a number of health experts. Suggested dose is 500 mg twice a day for 90 days. We use this. It is also in the CANCERactive Para Free Plus.
* Pau d’Arco – Another antiviral, this time from a South American tree bark, which treats Herpes – especially simplex (HSV), and Herpes I and II.. Suggested dose is 1000 mg twice a day for 90 days. We also use this.
* Licorice root – The active ingredient against EBV is Glycyrrhizic acid.
* Monolaurin which is derived from lauric acid. This seems particularly active against Epstein-Barr. Coconut oil contains high quantities of lauric acid.
When we used a combination of 12 weeks Pau d’Arco, alongside oregano oil 180 mg x 2 for 7 days then 400 mg Artemisinin for 7 days, in total 6 times, one cancer patient reported that her herpes, which had been active for 20 years, disappeared.
Woman’s grapefruit-size ‘liver cancer’ tumor was actually a parasite
A dull ache in her right ribs led to a grim diagnosis, then a startling discovery.
Feb. 13, 2020, By A. Pawlowski
At 36, Cassidy Armstrong thought she was facing a death sentence.
After years of vague pain on her right side, scans of her body revealed a grapefruit-size mass growing on her liver, which doctors diagnosed as a rare malignant cancer. It came with a grim prognosis: She was told that even with treatment, she’d likely succumb within a few years.
“I was getting ready for the worst, I was getting ready to die,” Armstrong, who lives in Edmonton, Alberta, told TODAY.
But when the mass was removed last fall and a pathologist looked at it under a microscope, it turned out to be a rare parasite that likely had been growing inside her body for at least a decade. Armstrong still remembers the moment doctors told her the news.
Read the full story on today.com
Where can I get these treatments?
If you are unable to source Ivermectin, Fenbendazole, or Mebendazole please email tommy@cancerireland.ie for supplier details.
Last updated April 2026