What is Cryptosporidium?

Cryptosporidium is a protozoan parasite often found in general watercourses, as well as raw water reservoirs. Many raw water sources are located in rural areas where sheep, cattle and other wildlife (deer, rabbits, foxes etc.) are present. The parasite can remain within the body of the infected animal, multiplying many times and then can be spread through the animal faeces onto the land. Each oocyst is on average 4 – 6 µm in diameter and can exist in water and damp environments for several months.

Not all animals or people infected by Cryptosporidium will display symptoms. However they will spread the parasite and the resultant disease, Cryptosporidiosis. This has fever like and gastro-intestinal symptoms and can be life threatening for the young, elderly or those with compromised immune systems.

As described above Cryptosporidium oocysts are found in areas where intensive farming and/or wildlife is present. Depending on soil types and geology of an area, precipitation falling on the land surface may infiltrate surface soil and percolate through sedimentary rock strata introducing Cryptosporidium into aquifers or rock fissures.

Where abstraction via boreholes is undertaken then compromised water quality will result, necessitating enhanced treatment to ensure complete removal of Cryptosporidium oocysts.

There are a number of ways to sample water for the presence of Cryptosporidium. The most effective being a sample of at least 1000L of raw water taken over a 24 hour period. Any evidence of Cryptosporidium oocysts in a sample may mean a failure in the water treatment process or more robust land and animal management in the catchment area.