What is Cryptosporidium?
Cryptosporidium is a protozoan, or single-celled parasite, that can live in the intestines of warm blooded animals and people. It infects humans, animals such as cattle and sheep, and sometimes, dogs, cats, rodents, and birds. Cryptosporidium, meaning "hidden spores" in Greek, can grow only in a living host and does not multiply in the environment. Unlike many bacteria, such as E. coli, that quickly die off in water, Cryptosporidium spores, or oocysts, can live for several months.

How does Cryptosporidium enter our water?
Surface waters can be contaminated by effluent discharged by wastewater treatment plants, or by runoff from certain agricultural operations and urban areas. Wildlife may also be a source of waterborne cysts such as Cryptosporidium.

Generally speaking, water from wells should be free from Cryptosporidium because the soil should filter out the protozoan before it reaches the groundwater. Properly constructed and maintained wells, not under the influence of surface water, should be relatively free from oocysts. Disinfection and filtration processes used in surface water treatment plants usually do a very good job of eliminating Cryptosporidium. Most disease outbreaks are from treatment plant breakdowns or rapid changes in the quality of raw water. Unfortunately, disinfection alone, during these rapid changes, is not very effective because the oocysts are very resistant to most disinfectant products, such as chlorine. Ultraviolet light is effective against Cryptosporidium provided the water is clear.

How does Cryptosporidium affect human health?
The symptoms of cryptosporidiosis are watery diarrhoea, stomach cramps, loss of appetite and vomiting. Symptoms normally appear within 2 to 25 days after infection and usually last one to two weeks in healthy individuals. In healthy people, this illness will usually clear up without being treated. However, some people may have to be treated. Parasites, in particular Cryptosporidium, can be a more serious threat to people whose immune systems are not working properly, such as those living with HIV/AIDS or cancer, or transplant patients receiving drugs. For these people, the symptoms can be life-threatening and the conditions may become chronic.

How does Cryptosporidium affect the aquatic environment?
Although it is not likely to have a significant effect on aquatic life, very little is known about Cryptosporidium effects in this area and there are no guidelines for the protection of aquatic life. However, there is growing concern about pathogens in general. For example, outbreaks of botulism produced by Clostridium botulinum another waterborne pathogen, have caused large numbers of waterfowl deaths in Canada. There are also new fungal and viral pathogens contributing to significant declines in amphibian populations around the world. There have also been beach closures, shellfish harvesting closures, and contaminated irrigation waters for human food supplies and animal feed.

What are the Cryptosporidium guidelines?
The Federal-Provincial-Territorial Committee on Drinking Water has developed a Guideline for Canadian Drinking Water Quality for Cryptosporidium. However, no maximum acceptable concentration has been established for it, as the current detection methods are not very reliable. The guideline does, however, encourage water treatment authorities to implement measures aimed at reducing the risk of illness as much as possible. These measures address the protection of the source water as well as modifications to the treatment and distribution of the water.

• Drinking Water Guidelines

What can individuals do to help?
To avoid pathogens ( such as Cryptosporidium) and their effects:

• When outdoors, it is best to assume that surface water is contaminated and boil it for 1 minute before use for drinking, food preparation or tooth brushing.
• Avoid drinking water directly from rivers, creeks or lakes, or when you are uncertain whether the water has been properly treated.
• Avoid swimming in recreational water (pools, hot tubs, lakes or rivers, the ocean, etc.) if you have diarrhoea and for at least 2 weeks after diarrhoea stops.
• Pick up pet droppings and dispose of them hygienically.
• Take limited amounts of food to beaches to avoid attracting animals and birds that leave droppings. Don't feed animals or birds, and securely close garbage bins.
• Ensure septic systems are operating properly.
• Practice pollution-free boating and dispose human waste properly.
• Encourage proper wastewater treatment by your municipality and local industries.
• Properly maintain livestock, and try best management practices such as a buffer area between the cattle and the stream.