NO. IO COCKROACHES—ROTH AND WILLIS 27 
This belief of Cram’s was vindicated by Brumpt and Urbain (1938, 
1938a), who found that the acanthocephalids Prosthenorchis elegans 
and Prosthenorchis spirula, which in nature are found in monkeys, 
lemurs, and coati, were able to adapt easily to new hosts found in 
zoological parks. These worms developed there in the German cock- 
roach which, though probably not a host in the forests where the 
normal primary hosts are found, was capable of maintaining and 
spreading infection in zoos. 
The rat parasite Gongylonema neoplasticum occurs naturally in at 
least four species of cockroaches which serve as intermediate hosts. 
The work of Fibiger with G. neoplasticum in relation to rat cancer 
is of interest because for it he was awarded a Nobel prize in 1926. 
However, this work provoked a controversy of acclaim and criticism 
that has continued up to the present time. Fibiger (1913, 1913a) 
believed he had found a correlation between the presence of G. neo- 
plasticum and the occurrence of stomach tumors in rats. The argu- 
ments about the importance of parasites in the production of cancer 
(see Anonymous, 1913; Sambon, 1924, 1926a; Simpson, 1924; 
Yokogawa, 1924, 1925a; Goyanes, 1926; Leiper, 1926; Oberling, 
1944) have been resolved only recently. Hitchcock and Bell (1952), 
using Gongylonema neoplasticum, in carefully controlled experiments 
failed to produce acceptable malignant lesions in rats. They showed 
further that lack of vitamin A in the diet heightens the deleterious 
effect of the parasites; rats that were maintained on a diet deficient in 
vitamin A developed pathologic changes similar to those described by 
Fibiger. Hitchcock and Bell concluded that G. neoplasticum acts as 
a biologic, chronic irritant and produces only minimal effects on the 
forestomach epithelium in the absence of concurrent nutritional 
deficiency. 
Sondak (1935) found cockroaches, captured in places where food 
was prepared in Leningrad, carrying normal eggs of Enterobius 
vermicularis and Trichuris trichiura; as a result, he concluded that the 
most radical measures must be undertaken to destroy cockroaches in 
places where food is prepared and served. He cited a 1930 report by 
Filipchenko and Dansker on conditions contributing to infection of 
communal eating places and children’s institutions by eggs of parasitic 
worms of man. They had found eggs of Taenia sp., Ascaris lumbri- 
coides, and T. trichiura on dining tables, chairs, benches, and even 
on dishes. Although admitting that fouling of these objects can be 
due to insufficient cleansing of the hands, Sondak pointed out that 
cockroaches, crawling through a dirty environment, can also be a 
mechanism for carrying eggs of these parasites. 
