Cercarial Dermatitis — Chu 
305 
fewer snails, associated with the weed Ranun- 
culus fluitans . The definitive host, the teal 
Fuligula novae zealandii , rested on the weed 
beds through the summer and fed on the lake 
floor. The adult stage of C. longicauda has not 
been studied. 
8. Australia 
Fresh-water cercarial dermatitis has been 
known in Australia since Johnston (1941) 
first reported its presence in the Murray Valley 
swamps. He surmised that Cercaria parocellata 
Johnston and Simpson, 1939, from Limnaea 
lessoni , on morphological grounds, might be 
the parasite involved. Macfarlane (1952) made 
a further investigation and obtained reports 
of dermatitis at Albury, Birri, Loxton, Man- 
num, Murray Bridge, and Tailem Bend near 
Adelaide. According to this author, at all of 
these places the river spread into areas of 
shallow water, which allowed the molluscan 
hosts to build up a population in close associ- 
ation with water birds. He believed that most 
of the infection of humans occurred during 
periods of shallow water. 
Swimmer’s itch was also known to be pres- 
ent in Western Australia. Lake Bumbleyung 
in the Wagin region appeared to be the im- 
portant area although other smaller lakes had 
also been the source of the infection. The 
third area in Australia suspected to have cer- 
carial dermatitis was Narrabeen Lake, a small 
shallow coastal lake near Sidney. It has been 
reported since that these cases were caused by 
marine species of bird schistosomes, because 
this lake has an outlet to the Pacific Ocean 
and the water may not be fresh. 
Macfarlane reported that the snail inter- 
mediate host L. lessoni occurred in both the 
Murray Swamp area and the Wagin region. 
Whether or not Cercaria paracellata was in- 
volved in both areas is not known. In the 
Murray River, L. lessoni lived in the often 
stagnant backwaters. 
Johnston (1941) suspected that the black 
swan was the definitive host for C. parocellata , 
but confirmation has not been made. Cercaria 
jaenschi was reported by Macfarlane (1952) 
not to penetrate the skin of man even though 
it was a schistosome cercaria. Furthermore, 
the antigen prepared from these cercariae 
produced smaller and less persistent skin re- 
actions than did the C. parocellata antigen. 
B. MARINE CERCARIAL DERMATITIS 
1. California and Mexico 
Extended studies of marine snails as possi- 
ble agents in the transmission of cercarial 
dermatitis were not made until several years 
after World War II. However, as early as 1942, 
Penner mentioned that the marine gastropods 
might be infected with dermatitis-producing 
schistosome cercariae. In 1950, he described 
as a new species Cercaria littorinalinae from 
the marine snail Littorina planaxis Philippi, 
which were collected along the rocky shores 
of the Coronado Islands in Mexico and from 
Bird Rock near La Jolla, California. The natu- 
ral definitive host was the Wyman western 
gull ( Larus occidentalis wymani Dicky and 
van Rossem). Penner (1953c) was able to in- 
fect experimentally with this species of cer- 
caria the following birds: brant, cormorant, 
black-crowned night heron, western gull, 
budgerigar parakeet, Australian zebra finch, 
domestic pigeon, red jungle fowl, and linnet. 
The domestic duck did not appear to be 
susceptible to the infection. The adults of C. 
littorinalinae belong to the genus Austrobil- 
harzia (Johnston, 1917) and have been given 
the name Austrobilharzia littorinalinae by Pen- 
ner although the taxonomic description is 
still unavailable. This species of schistosome 
is therefore distinct from A. variglandis (Miller 
and Northup, 1926) Penner, 1953 ( = Microbil- 
harzia variglandis (Miller and Northup, 1926) 
Stunkard and Hinchliffe, 1951). 
In the San Diego area, this marine species 
of bird schistosome has not been officially in- 
criminated in cases of swimmer’s itch al- 
though Penner (1950) did mention that he 
experienced the development of typical le- 
sions after wading in sea water in this area 
