Q: I have a question about natural hot springs in Iceland (we’re planning a hiking tour). A friend went to Iceland several years ago and reported that bathing in natural hot springs is no longer recommended due to cases of swimmer’s itch (bird/snail parasites in fresh water). I looked around for days and could find some reports dating back to 1999, 2003, 2004... but not anything that really helps.
A: The protists that cause swimmer’s itch were first discovered in a natural hot spring in Iceland in Landmannalaugar about a decade ago. At that time, the Directorate of Health issued a warning, advising people to avoid natural hot springs, particularly late in the year, from August to December or so, as the warm water attracts birds, the hosts of the adult protists, during those months before they migrate south for the winter.
Many people still enjoy bathing in hot springs, and there is no regulation banning people from swimming there. People are advised against touching vegetation in the water as water snails, the hosts of the immature protists that cause the actual rash, hide there. It is not recommended that those who generally have severe allergic reactions to insect bites, such as mosquito bites, bathe in the springs.
Most evidence points to these protists not being able to fully mature in humans, and they die soon after attempting to enter the human body. Some researchers however speculate that the protists may be able to cause damage to the nervous system of mammals, although that research is still rudimentary and the verdict is still out on whether or not they can cause serious damage to humans.