Irish people are unwittingly exposing themselves to the dangerous parasite Cryptosporidium when they use our waterways for recreational purposes, according to one expert.
Dr Frances Lucy, an ecologist and lecturer at the Department of Environmental Science at IT Sligo believes that cryptosporidium is “widespread in the aquatic environment”. And she warned that anyone who feels ill following water sports on our lakes and rivers should contact a doctor.
Her concerns are based on tests carried out on samples taken from Lough Gill, Co Sligo and from the river Liffey, as part of a joint research project being undertaken by IT Sligo and UCD.
The study which is being funded by the Environmental Protection Agency under the STRIVE programme, hopes to establish why there is a spring peak in the number of human cryptosporidiosis cases in Ireland. Researchers hope to determine whether there is a link to the lambing and calving season and if not, what the most likely sources are. “We don’t know enough about sources or seasonality and we hope that by looking at human, animal and environmental samples, we may be able to establish scientific trends which could help the health authorities with risk assessment and management, “explained Dr Lucy.
Cryptosporidium was identified as a serious public health risk following a severe outbreak in Galway in 2007 when hundreds of people were affected, and a boil water notice was in operation for six months. Tests found that most people were infected with a Cryptosporidium strain found in human waste.
The current research project on Lough Gill and the Liffey will not be completed until next year but the findings so far are “worrying”. Researchers led by Dr Theo de Waal from the School of Agriculture, Food Science and Veterinary Medicine at UCD and Dr Lucy, took a series of samples at both locations from March to October in 2009 and in 2010. The tests were analysed at IT Sligo, UCD and at the Johns Hopkins University in Baltimore in the US. Cryptosporidium was found “in almost every sample”.
While Lough Gill is the main source of drinking water for this part of Co Sligo and parts of Leitrim, Dr Lucy stressed that the water treatment system used by Sligo County Council is state of the art, and said there was no risk to public health from drinking the water once it is treated.
Her warning relates to the dangers for people who unwittingly swallow water while swimming or taking part in water sports. “I believe that exposure during recreational activities is very under-studied,” said the ecologist. “When we were on site at Castletown House in Celbridge, Co Kildare, taking samples from the Liffey, there were kids jumping into the water. People do swallow water when playing like this and everyone knows that small children tend to defecate in water”.
With the final report due to be published in the middle of 2012, Dr Lucy revealed that the preliminary findings suggest that contamination in both locations is due to both animal and human waste. She pointed out that slurry was found to be contaminated and that the slurry spreading season in Ireland continues until mid-October.
Based on her previous research, Dr Lucy believes that had the samples been taken on any lake or river, the result could have been the same. “I believe it is widespread in the aquatic environment. If we had picked any lake in the North West we would have found Cryptosporidium”.
She believes many cases are not being recorded. “People in Ireland are very slow to go to a doctor if they have cramps or diarrhoea – men especially are inclined to say ‘I got a bad pint’ – but if people feel ill after being in the water, they should be aware that it could be Cryptosporidium and they should see a doctor”.
During her research Dr Lucy found a use for the dreaded zebra mussel which has been interfering with biodiversity on Irish water systems since the 1990’s. “Because zebra mussels filter water, as much as a litre a day, we knew that if Cryptosporidium was present in Lough Gill we would find it in this species, “she pointed out. The research team removed zebra mussels from Lough Gill and water hog louse from the Liffey and tested both for Cryptosporidium.
Given that many people living in the west of Ireland people use local group water schemes which are supplied by lakes, Dr Lucy said adequate water filtration system are vital. “It is probably surprising that there have not been more outbreaks but that may be because we have such strong immune systems as we don’t live in a sterile society,” said Dr Lucy.