Cryptosporidiosis is a parasitic infection of the small intestine. Diarrhea is the main symptom, but in people with compromised immune systems, the symptoms can be severe or even fatal. Crypto has been successfully treated with colloidal silver and zinc.
https://www.medicalnewstoday.com/articles/190664?utm_source=newsletter&utm_medium=email&utm_campaign=MNT%20Weekly%20News&utm_content=2020-09-30&utm_country=CA&utm_hcp=yes&apid=25283264&utm_term=MNT%20Weekly%20News
Parasites – Cryptosporidium (also known as “Crypto”) – CDCwww.cdc.gov › parasites ›
Cryptosporidium is a microscopic parasite that causes the diarrheal disease cryptosporidiosis. Both the parasite and the disease are commonly known as “Crypto.” There are many species of Cryptosporidium that infect animals, some of which also infect humans.
Cryptosporidium infection – Symptoms and causes – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/cryptosporidium/symptoms-causes/syc-20351870
Swimming pool sickness Can you get sick by swimming in public pools? The Centers for Disease Control and Prevention says outbreaks of a parasitic infection called cryptosporidia are being reported more frequently. The bacteria, which are hard to eradicate with standard levels of chlorine, can cause many symptoms, including watery diarrhea.
https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-minute-swimming-pool-sickness/
Silver as a drinking-water disinfectant: nanoparticles may reduce the infectivity of Cryptosporidium oocysts (Abebe et al
https://www.who.int/water_sanitation_health/publications/silver-02032018.pdf?ua=1

Point-of-Use Removal of Cryptosporidium parvum from Water: Independent Effects of Disinfection by Silver Nanoparticles and Silver Ions
https://pubs.acs.org/doi/10.1021/acs.est.5b02183

Modern Tools and Methods of Water Treatment for Improving Living Standards pp 159-166| Cite as

Water Disinfection Using Silver and Copper Ions and Colloidal Gold https://link.springer.com/chapter/10.1007/1-4020-3116-5_12
Silver Nanoparticles as a Novel Approach to the Treatment of Chronic Lyme Disease and Associated Diseases. Chronic Lyme disease patients are often afflicted with more than just borreliosis. The symptomatology and diagnoses of such patients is complicated, often involving multiple infections affecting every organ system in many cases. Such patients often suffer from chronic viral infections, multiple bacterial, parasitic, and protozoal infections, as well as chronic fungal and mold infections.
by Nooshin K. Darvish, ND, FICT
https://www.townsendletter.com/July2016/silver0716.html