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Parasitology

Detection of Cryptosporidium and Giardia in Water

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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 Litre Grab samples.

 

Irish Regulations

Under the European Communities (Drinking Water) Regulations, 2000, there is a requirement to monitor for the presence of Cryptosproridium if Clostridium perfringens have been detected in the water.

 

Getting Started

There are two main ways to test for Cryptosporidium in water:

1. 10 Litre Grab Sample

This simple method of sampling involves sending a 10 litre sample to the laboratory for analysis. This is useful on site for when 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 litres) is filtered through a commercially available filter on site and the filter is then sent to the laboratory for analysis. This is the UK DWI accepted method for detection of Cryptosporidium in water. Analysing a more representative sample of water will ensure a more accurate result.

Recommended Sample Volumes:

  • Drinking Water  1000 Litres
  • Raw Water        50 Litres

 

On - Site Filtration

There are two commercially available filters that 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

Pall Envirocheck Filter

 

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 also supply the Filta Max filters for use with the rig.

Download Cryptosporidium Rig Sampling Guidelines here.

 

Sample Submission

Once filtered, the sample should be sent along with the filter to the laboratory for analysis.
If requested a turn around time of 24 hrs can be achieved for these samples. It is advised that the sample arrive at the laboratory within 24hrs of filtration.


 
What is Cryptosporidium?

Crytposporidium is a protozoan parasite and is one of the most common causes of gastroenteritis in the developed world. The infectious stage of the life cycle is an environmentally resistant 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 disease.

 

More details about our service can be found with our Crytposporidium test kits.

 

Cryptospoidiosis fact http://en.wikipedia.org/wiki/Cryptosporidium

 

Method Basics

 

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 specialised 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 possible to filter the sample a ten litre 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 antibody to the oocyst wall protein and DAPI stain which stains the nucleic acids in the (oo)cysts.