Post by coyote on Sept 30, 2010 20:33:48 GMT
From the San Francisco Chronicle:
"An invasive snail recently discovered in San Francisco Bay has brought along its own unwelcome stowaway: a parasitic worm responsible for only the second known outbreak of "swimmer's itch" along the Pacific Coast of the United States.
. . . Swimmer's itch, or cercarial dermatitis, normally crops up in freshwater. It is an immune system reaction caused when a certain type of parasite emerges from snail shells and attempts to burrow into a host's skin. Usually, the parasite - a microscopic flatworm with a forked tail - bores into the legs and feet of birds, hitches a ride in the bloodstream and settles in the intestines to breed. In people, the worms are rejected and the rash subsides in a couple of days, or, at most, in a couple of weeks.
Over the past five years, researchers say the worm has wriggled into Bay Area beachgoers' bathing suits from the Japanese bubble snail (Haminoea japonica), a three-quarter-inch-long gastropod first identified in San Francisco Bay 10 years ago and in Alameda in 2003. Researchers can't pinpoint exactly how the Asian snails made their way to Northern California. But they may have hitchhiked in shipments of oysters for farming or in the ballast tanks of cargo ships, which are filled with or emptied of water to stabilize the vessels depending on the size of their cargo loads.
. . . "People think of invasive species as an environmental problem,"
Read more: www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2010/09/30/MNAT1FLPHC.DTL
Image of the Japanese bubble snail:
www.sfgate.com/cgi-bin/object/article?f=/c/a/2010/09/30/MNAT1FLPHC.DTL&o=1
"An invasive snail recently discovered in San Francisco Bay has brought along its own unwelcome stowaway: a parasitic worm responsible for only the second known outbreak of "swimmer's itch" along the Pacific Coast of the United States.
. . . Swimmer's itch, or cercarial dermatitis, normally crops up in freshwater. It is an immune system reaction caused when a certain type of parasite emerges from snail shells and attempts to burrow into a host's skin. Usually, the parasite - a microscopic flatworm with a forked tail - bores into the legs and feet of birds, hitches a ride in the bloodstream and settles in the intestines to breed. In people, the worms are rejected and the rash subsides in a couple of days, or, at most, in a couple of weeks.
Over the past five years, researchers say the worm has wriggled into Bay Area beachgoers' bathing suits from the Japanese bubble snail (Haminoea japonica), a three-quarter-inch-long gastropod first identified in San Francisco Bay 10 years ago and in Alameda in 2003. Researchers can't pinpoint exactly how the Asian snails made their way to Northern California. But they may have hitchhiked in shipments of oysters for farming or in the ballast tanks of cargo ships, which are filled with or emptied of water to stabilize the vessels depending on the size of their cargo loads.
. . . "People think of invasive species as an environmental problem,"
Cohen said. "But we need to remind people that there are serious health impacts of not dealing with invasions."
Read more: www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2010/09/30/MNAT1FLPHC.DTL
Image of the Japanese bubble snail:
www.sfgate.com/cgi-bin/object/article?f=/c/a/2010/09/30/MNAT1FLPHC.DTL&o=1
