The Morphology and Life-History of Microbilharzia variglandis (Miller and Northup, 1926) Stunkard and Hinchliffe, 1951, Avian Blood-Flukes Whose Larvae Cause "Swimmer's Itch" of Ocean Beaches

Abstract

A dermatitis of fishermen and bathers in the Narragansett Bay area of R. I. is caused by the cercariae of avian schistosomes. The larvae, which develop in simple sporocysts in the mud-snail, Nassa obsoleta, are identified as Cercaria variglandis. The dermatitis is similar clinically to "sea-bather''s eruption" as reported in New York, Florida, California and Hawaii. It has been produced by C. variglandis in persons sensitized to this species and in others, sensitized to larvae of fresh-water schistosomes but with no previous exposure to marine cercariae. The antigenic substances of marine and fresh-water avian schistosomes are therefore very similar if not identical. Sexually mature worms, recovered from the mesenteric veins of experimentally infected canaries, pigeons, gulls and ducklings, are morphologically identical with specimens found by Chapin in the lesser scaup duck, Marila affinis, in Maryland and described as Microbilharzia chapini by Price, 1929. In a preliminary report Stunkard and Hinchliffe designated the parasite M. variglandis (Miller and Northup, 1926).