People urged to avoid swimming in Lake Tutira
Hawke’s Bay DHB Medical Officer of Health Dr Nicholas Jones says that the mostly likely cause of rash occurring among swimmers at Lake Tutira is “swimmers itch”. Also known sometimes as “duck itch” the rash is due an allergic reaction to bird parasites. Dr Jones said he is not aware of swimmers itch occurring previously in Hawke’s Bay but it has been known to cause problems in other parts of the country such as Lake Wanaka.
It is possible that only some areas of the lake are affected.
Dr Jones advice at this time is to avoid swimming in Lake Tutira. If people do choose to swim it would be particularly important to avoid swimming in the shallow waters at the lake edge. This makes it particularly difficult for parents with young children so parents may decide it is safer to keep children out of the water altogether or anywhere near the lake edge.
People who are experiencing itch or rash after swimming at the lake should see their family doctor for assessment and treatment. To discuss other concerns or report where the rash occurred please contact the DHB’s Public Health Unit available through 06 878 8109.
Dr Jones said signs were erected on Thursday at the lake to warn visitors and the DHB was working with the Regional Council to further assess both immediate and longer term risks.
How does “swimmers itch” occur?
Swimmers itch or duck itch is a rash due an allergic reaction to bird parasites The parasites have a life cycle that relies on growth in snails before re-infecting aquatic birds, the snails tend to live in the shallow water around the lake edge
If someone is unfortunate enough to swim at a location where snails are releasing the parasite the rash is likely to occur as the parasite enters the swimmers skin. Although the parasite does not survive in humans the rash occurs because of the body’s immune system reaction.
Swimmers may initially experience itch or tingling on leaving the water which develops into an intense itch over a number of hours as red spots enlarge to form pimple like bumps. The rash usually only occurs in areas of the body that have been exposed to the affected water.
How is “swimmers itch” treated?
When there are only a few spots no treatment may be necessary. Otherwise the skin should be lightly rinsed with (rubbing alcohol) and coated in calamine lotion. Antihistamine or mild corticosteroid cream can be helpful.
For some forms of the parasite brisk towelling immediately after swimming can reduce the risk of a reaction developing. However at this stage not enough is known about the cause to determine whether towelling would be helpful in this instance.
More information is available at dermnetnz.org
HBDHB MEDIA STATEMENT 13 January 2012