When a microscopic organism needs to survive harsh environments, it will sometimes form a thick egg-like coating and enter a dormant state, also known as a cyst. Parasites become cysts to survive their journey when moving from host to host. Once the parasite enters a new host or more survivable environment, it will "hatch" from its shell and carry on with its normal dirty work.
The most common types of cysts that are harmful to humans are giardia and cryptosporidium. These are intestinal parasites that, when ingested, can cause chronic intestinal disease. Only half of people infected with giardia may show symptoms.
Symptoms of these parasites include:
- Loss of appetite
- Excessive gas (flatulence or sulphuric-tasting burps)
- Abdominal cramps
Refrigerator water filters that can remove microbial cysts include: