There are no reliable methods available to detect Giardia and Cryptosporidium parasites on a routine basis. Current tests can take a few days to come up with the results which means they aren’t very good for day-to-day monitoring. Click here or the pdf file to read the full article or an excerpt below.
Are water supplies tested for Giardia and Cryptosporidium?
Unfortunately, no reliable methods are currently available to detect these parasites on a routine basis. This is largely because the methods underestimate the number of organisms present and do not provide any information on their capacity to cause illness in humans. The tests that do exist take a few days to come up with results which means they aren’t very good for day-to-day monitoring. Research is underway in Canada and internationally to develop appropriate detection methods and treatment technology to safeguard drinking water against these parasites.
Is there a Canadian drinking water guideline for these parasites?
Yes and no. A guideline has been established for Giardia and Cryptosporidium, but because the current detection methods are not very reliable the guideline does not give a maximum acceptable concentration (MAC) value for these parasites in drinking water. The guideline does, however, encourage water treatment authorities to implement measures aimed at reducing the risk of illness as much as possible. The guideline states: “If the presence of viable, human-infectious cysts or oocysts is known or suspected in source waters, or ifGiardia or Cryptosporidium has been responsible for past waterborne outbreaks in a community, a treatment and distribution regime and a watershed or wellhead protection plan (where feasible) or other measures known to reduce the risk of illness should be implemented.”