Swimming water quality

Sylphium molecular ecology offers various eDNA tests for determining harmful (micro) organisms in swimming waters. The eDNA tests offer the possibility to quantitatively or qualitatively demonstrate the DNA of various organisms in water samples with very high sensitivity, specificity and reproducibility. The described analyzes are also offered as a kit. See the webshop for the specific qPCR kits.


Cyanobacteria, also known as blue-green algae, can pose a threat to public health in fresh surface waters during the summer months. For that reason, waters with a swimming function where blue-green algae can occur in high densities are intensively monitored during the summer months. According to the 2012 Blauwalgenprotocol, the amount of potentially toxic blue-green algae or the amount of microcystin is determined. If these exceed certain values, a warning or negative swimming advice is given. In the worst case, the bathing water is closed. This has far-reaching consequences for both water managers and operators of a recreational lake, usually with major financial damage, especially for the tourism sector. Due to the far-reaching economic and social consequences, a good estimate of the risk of blue-green algae is of the utmost importance. For a good risk analysis it is very important to be able to distinguish between blue-green algae that can potentially produce toxins and blue-green algae that cannot. This is not always easy to do with the microscope. Therefore, some administrators prefer to measure the toxin content in the water. However, this is also not a reliable method. The reason is that the toxin content in the water can fluctuate greatly in a short period of time, depending on the condition of the blue-green algae, the weather and the activity of microorganisms that break down toxins.

DNA technology offers the opportunity to demonstrate not only the presence of blue-green algae that can actually produce toxins, but also their amount. This analysis technique quantifies the amount of the genes responsible for toxin production. This creates the opportunity to make reliable statements about the toxic potential of a blue-green algae community.

Sylphium molecular ecology offers quantitative analysis for the following toxins: microcystin, anatoxin and cylindrospermopsin.

Swimmers itch

A common problem in recreational pools is swimmer’s itch. This is an allergic skin reaction caused by the parasite Trichobilharzia.

The traditional test to detect Trichobilharzia consists of collecting the host’s snails from the parasite. These collected snails are then placed in a laboratory under a lamp, after which any cercaria that may be present are released from the host. Microscopically, it is then examined whether these released cercaria belong to the harmful Trichobilharzia.

The eDNA technique developed by Sylphium is able to detect the parasite in surface water without having to collect snails and analyze them for the presence of cercaria. More information can be found here.

E.coli and enterococci

Escherichia Coli (E. coli) and intestinal enterococci (IE) are found in the feces of humans and animals. Most strains are harmless, but some strains can cause serious problems with their hosts. During the bathing water quality control it is measured whether and to what extent these bacteria occur in the water. Both bacteria groups are a good indication of the bathing water quality. Sylphium molecular ecology offers quantitative analyzes for both bacteria groups.

Weil’s disease (Leptospirosis)

Leptospirosis (also called rat disease, milk fever, mud fever or swamp fever) is caused by pathogenic species of the Leptospira bacteria. The bacteria can be transmitted by infected animals. Usually rodents transmit the disease. The transfer usually takes place through animal urine or through water or soil containing animal urine and coming into contact with open cuts in human skin, with the eyes or through the mucous membranes of the mouth or nose.

Weil’s disease occurs in the Netherlands. Half of the brown rats appear to carry Leptospira bacteria. It is seen as an occupational disease among sewer workers and (musk) rat fighters. The Netherlands is struggling with an increase in the number of cases. Weil’s disease is included in the World Organization for Animal Health (OIE) list B and is a notifiable disease. Sylphium molecular ecology offers a qualitative analysis to detect the disease-causing Leptospira bacteria in water.