Imagine
yourself frolicking on a warm, sandy beach on a sunny summer day. At mid day,
when the sun is at it's hottest, you decide to take a dip in the calm lake
water. Unsuspectingly, you enter the water, and it is not long before you
encounter this!
courtesy of Center for Disease Control
You
actually will not be able to see this, but in waters infested with schistosome
cercaria, these creatures will surely approach you. Ideally, they would like to
encounter birds or other mammals, but every so often humans cross their paths.
If these creatures are so small and puny, why should we be concerned? Although
the initial encounter will surely go unnoticed, in a few hours to days, you will
be left with an umpleasant reminder of their presence: a nasty, itch rash called
cercarial dermatitis, commonly known as "swimmer's itch." This webpage is my
attempt to provide a comprehensive overview of the condition cercarial
dermatitis as well as the organism that causes it, so click away and enjoy!
Synonyms
The common name for cercariae
dermatitis is swimmer's itch, which describes one of the most common ways humans
encounter this condition. Other names include "clam digger's itch", "diver's
itch", or other variations on the itch theme. Originally it was described as
schistosome dermatitis by Cort in 1928; however, in 1930, Vogel used the term
cercarial dermatitis, which is the name used to this day. In Japan, it was known
as karube or konganbyo if it was more severe.
History of Discovery
The earliest description
that I could trace back in the literature was a reference to an 1855 description
by LaValette of the erythemous maculo-papular eruption that is presumed to have
been cercarial dermatitis. In Japan, karube, a maculo-papular rash, was common
among rice farmers that spent lots of time in cercariae-infested water. At the
turn of the century, it was assumed that human schistosomiasis S. japonicum was
the cause of this rash. However, in 1913, Miyagawa began to cast doubt on this
presupposition. In the American scientific literature, Cort was the first to
demonstrate that swimmer's itch was caused by the cercariae of non-human
schistosomiasis in 1928. Prior to that, it was believed that all such eruptions
were caused by human schistosomiasis.
