Detection of Cryptosporidium and Giardia in Water
City Analysts have been monitoring drinking water in Ireland for the presence of Cryptosporidium and Giardia for nearly 10 years. Our experience in the field and expert staff offer a full service with advice on sampling, filtration, assessment and result analysis.
Our method is based on the UKs drinking water inspectorate published protocol in line with strict UK legislation. We participate in the "Crytps" external proficiency scheme ensuring our method is performing to UK regulations.
We can process Idexx Filta Max and Pall Envirocheck Filters along with 10 L Grab samples.
Under the European Communities ( Drinking Water ) Regulations , 2000, there is a requirement to monitior for the presence of Cryptosproridium if Clostridium perfringens has been detected in the water.
There are two main ways to test for Cryptosporidium in water:
1. 10 L Grab Sample
This simple method of sampling involves sending a 10 L sample to the laboratory for analysis . It is useful for when on site filtration is difficult but in general if possible on site filtration of larger volumes of sample is advised.
2. Large Volume Filtration
A large volume, up to 1000 L if filtered through a commercially available filter on site and the filter is sent to the laboratory for anlysis. This is the UK DWI accepted method for detection of Cryptosporidium in water, analysing a more representative sample of water resulting in a more accurate result.
Recommended Sample Volumes:
- Drinking Water 1000L
- Raw Water 50L
On - Site Filtration
There are two commercially available filters have been designed specifically to concentrate Cryptosporidium from large volumes of water. These two filters are the only filters that are approved by the UKs Drinking Water Inspectorate and detailed accredited protocols are used to ensure efficient recovery of oocysts from these filters.
Idexx Filta Max Filter - http://www.idexx.com/water/filtamax
Pall Envirocheck Filter- http://www.pall.com/laboratory_7373.asp
City Analysts Cryptosporidium Filtration Rig
We can organise to send one of our rigs to your site to filter your sample. The rig is very portable and can be set up to connect to nearly any sampling point. The simple design is very easy to use and comes with detailed instructions. It is equipped with an Idexx Filta Max housing unit and we can supply the Filta Max filters for use with the rig.
Download Cryptosporidium Rig Sampling Guidelines here.
Once filtered the sample should be sent with the filter to the laboratory for analysis.
If requested a turn around time of 24 hrs can be achieved for samples. It is advised that the sample arrive at the laborabory within 24hrs of filtration.
Crytposporidium is a protozoan parasite that is one of the most common causes of gastroenteritis in the developed world. The infectious stage of the life cycle is an environmentally resistent oocyst measuring around 5 um in diameter. This oocyst is shed in the faeces of the infected host and can be transmitted via water or food that has become contaminated with animal or human sewage. Cryptosporidiosis is characterised by fever, severe abdominal pain, diarrhoea and vomiting which can last up to two weeks in immunocomptent individuals. The disease can become life threatening in immunocompromised individuals as there is currently no effective treatment for the diease.
Cryptospoidiosis fact http://www.ndsc.ie/hpsc/A-Z/Gastroenteric/Cryptosporidiosis/Factsheet
The protocol for this method has been described in detail by Uk's Drinking water Inspectorate and the US EPA.
The method is based on concentrating the (oo)cysts from water using specalised filters. There are two commercially available filters that have been approved for Cryptosporidium detection, the Envirocheck Filter from Pall and the Filta Max from Idexx. City Analysts can process samples that have been concentrated using either filter. If however it is not possilbe to filter the sample a 10 L grab sample can be sent to the laboratory for analysis.
Once filtered the (oo)cysts are then eluted from the filter and isolated by immunomagnetic separation. This technique captures the (oo)cysts on antibody coated magnetic beads allowing the sample interferants to be discarded.
The final stage in detection is staining and microscopy. The (oo)cysts are fixed onto slides and stained twice using FITC labelled anitbody to the oocyst wall protein and DAPI stain which stains the nucleic acids in the (oo)cysts.