Cercarial Dermatitis — Chu 
303 
Washington, Oregon, and California. Thus it 
is no surprise that swimmer’s itch along the 
Pacific coast has been reported from Alaska 
to El Salvador. 
4. Japan 
On the western side of the Pacific Ocean, 
the Japanese have recognised for over 50 
years the existence of a dermatitis of unknown 
etiology which occurred among farmers in- 
habiting land near Lake Shinji, Shimane Pre- 
fecture. The dermatitis is called "koganbyo” 
or 'lakeside disease” (Hunter, Ritchie, and 
Tanabe, 1951). 
These authors reported that Tanabe in 1947 
was able to produce experimental dermatitis 
using the furcocercous cercariae from a spe- 
cies of snail now known as Polypylis hemi- 
sphaerula Benson. This observation was con- 
firmed and subsequently the definitive hosts 
were determined. They are the large starling 
( Spodiopsar cineraceus Tamminck), the sparrow 
(. Passer montanus saturatus Stejnerger), and the 
wagtail ( Motacilla ( Motacilla ) grandis Sharpe). 
The adult of this species of schistosome is 
designated as Gigantobilharzia sturniae Ta- 
nabe, 1948. 
The snail intermediate hosts (with 3-10 
per cent infections) were commonly found on 
submerged vegetation or mud of rice fields 
and irrigation canals. Dermatitis began in 
mid-May and reached a peak about mid-July 
to mid-August, and the degree and intensity 
of the infection appeared to be correlated 
with the aquatic activity of the rice farmers. 
Surveys made of other areas in Japan indi- 
cated that both the bird definitive hosts and 
the snail intermediate hosts were widespread. 
Aside from Lake Shinji, the cases of derma- 
titis in the farmers of Mie Prefecture as well 
as those of Aichi Prefecture were believed to 
be caused by the cercariae of G. sturniae (Oda, 
1956^, 1956b). It is possible that there are 
other areas in Japan where koganbyo exists. 
Yamaguti (1941) reported the presence of 
avian schistosomes in Japanese birds and 
described two new species: Trichobilharzia 
corvi (Yamaguti, 1941) McMullen and Beaver, 
1945, from Corvus cor one corone Linn., and 
Ornithobilharzia emberizae Yamaguti, 1941, 
from Emberiza sulphur ata Temm. et Schleg. 
However, it is not known if these parasites 
are capable of producing cercarial dermatitis. 
An interesting report was made by Ito 
(1956) on a brackish water furcocercous cer- 
caria from a snail intermediate host, Tympa- 
notonus microptera (Kiener) found in Chiba 
Prefecture (Tokyo Bay). The author named it 
Cercaria tympanotoni and suggested that on 
morphological grounds this cercaria might be 
dermatitis producing. Because of an insuffi- 
ciency of snails infected with this parasite, no 
experimental data were obtained. However, 
this record indicates, for the first time in 
Japan, that perhaps in a brackish water en- 
vironment there is a possibility of humans 
contracting cercarial dermatitis. 
5. China and Formosa 
There are no reported cases in man of avian 
cercarial dermatitis in China or Formosa. 
However, two species of bird schistosomes 
have been found in China; Ornithobilharzia 
odhneri Faust, 1924, from the Asiatic curlew, 
and Ornithobilharzia hoepplii Tang, 1951, from 
Swinhoe’s snipe. 
In Formosa, one species of avian schisto- 
some, Trichobilharzia yokogawai (Oiso, 1927) 
McMullen and Beaver, 1945, has been iso- 
lated from the duck. The "nonhuman 200 - 
philic” strain of Schistosoma japonicum in For- 
mosa has been regarded as a dog strain, be- 
cause there is a high incidence (62 per cent) 
of natural infections in dogs but no known 
occurrence in humans (Hsu et aL , 1954). In 
order to determine the effectiveness of this 
strain in causing cercarial dermatitis and other 
symptoms in man, Hsu and Hsu (1956) 
tested the infectivity of this strain of S. japoni- 
cum on five human volunteers. The cercariae 
of S. japonicum did cause the sensation of 
itching and the development of a rash or 
papule. There were systemic clinical signs, 
such as abdominal pain, headache, nausea, 
