Cercarial Dermatitis — Chu 
307 
illations. The exact relation of the sea birds to 
the problem of transmission and reservoir 
hosts in Hawaii has yet to be determined. 
The snail intermediate host, L. pintado, un- 
common in Micronesia and apparently lim- 
ited in its range to the northern Pacific 
islands, has been reported by Demond (1957) 
to exist in southern Japan, the Ryukyus, 
Bonins, northern Philippines, Marianas, Mar- 
shalls 4 , Johnston Island, and Formosa. The 
experimental snail intermediate host used by 
Chu and Cutress, Littorina scahra L., has a 
much wider geographical range: from east 
Africa through the Indian and Pacific oceans 
to Hawaii and Tahiti, and from the Ryukyus, 
the Philippines, and Marianas, south to north- 
ern Australia. Since both the definitive and 
intermediate hosts for A. variglandis are wide- 
ly spread in the Pacific area, one may surmise 
that marine schistosome infections of birds 
and snails may not be limited to the Hawaiian 
Islands and California and that with further 
investigation other areas might prove to be 
infected. 
In determining the casual agent of swim- 
mer’s itch, or cercarial dermatitis, it is not 
sufficient to find schistosome-infected snails 
in the area because of the possible presence of 
other etiological agents which cause similar 
skin lesions. "Swimmers’ Itch’’ (or "Pearl 
Harbor Itch”) cases reported by Arnold and 
Bonnet (1950) are now suspected to have 
been cases of marine hydroid dermatitis, be- 
cause the discovery of a medusa ( Sarsia sp.) 
was made in the same location which Arnold 
and Bonnet reported to be a source of the 
dermatitis. This finding, together with the 
absence of schistosome-infected snails in the 
areas under study, suggests that these "Swim- 
mers’ Itch” cases of Arnold and Bonnet were 
not of cercarial origin (Chu and Cutress, 
unpublished data). 
It is necessary, however, to point out that 
4 In 1955, at Eniwetok, C. E. Cutress found L. 
pintado and ruddy turnstones in the area, but among 
the specimens examined by him no schistosomes were 
found (personal communication, 1957). 
in the Atlantic coast, (such as Mill cove in 
Maine, Narragansett Bay in Rhode Island, 
and Long Island Sound, N. Y.) cercarial 
dermatitis was reported to be associated with 
clam digging (Orris and Combs, 1950; Sinder- 
mann and Gibbs, 1953). The intermediate 
host is a mud snail, Nassarius obsoletus ( Nassa 
obsoleta ), which is also an intermediate host 
for the marine schistosome in California. This 
species is not found in Hawaii as Edmondson 
(1946) listed Nassa sertum Bruguiere as the 
only local species. In several surveys made 
during 1951-54 by the Hawaiian investiga- 
tors, the few bottom-dwelling gastropods 
from West Loch, Pearl Harbor, were never 
found to be infected with schistosome 
parasites. 
Demond (1957) listed Nassarius papillosus 
(Linn.) as occurring in Hawaii. As yet, there 
is no report indicating that this or any other 
species of Nassarius is an intermediate host 
for schistosome in the central and south 
Pacific. 
An example of the difficulty of determining 
the etiological agent for dermatitis caused by 
marine microorganisms is that reported by 
Strauss (1956) for the "Seabather’s Eruption” 
in Guantanamo Bay, Cuba. This investigator 
was unable to find any snails infected with 
schistosomes. Serological tests of the patients 
showed negative evidence for the presence of 
cercarial dermatitis. A more fortunate experi- 
ence than that reported by Strauss was given 
by Chu and Cutress (1955). Many construc- 
tion workers contracted dermatitis when in 
contact with sea water in Hilo Bay, Hawaii. 
Although in this area, Littorina pintado and 
the ruddy turnstone were seen, no schisto- 
some-infected snails were located. Instead, a 
marine hydroid, Syncoryne mirabilis (Agassiz, 
1852), was found growing profusely on the 
surface of the submerged rocks near the site 
of construction. By chemical treatment, the 
hydroids were destroyed and the dermatitis 
was controlled. 
Most of the conclusions incriminating ma- 
rine schistosome cercariae in cases of derma- 
