Pomatiopsis lapidaria, Its Occurrence in the Washington, D. C. Area and Its Laboratory Rearing in Comparison to That of Oncomelania spp.

Abstract

Many native snails of the United States were tested during and following World War II to determine their capacity to serve as intermediate hosts for Schistosoma japonicum, the Oriental blood fluke. Pomatiopsis lapidaria Say, an amnicolid found widely distributed in the eastern half of the United States, was the only species incriminated. Stunkard (1946) found that partial development of S. japonicum might occur in this species and Ward, Travis, and Rue (1947) made similar observations. Complete development of S. japonicum in P. lapidaria, with the production of cercariae infective for hamsters, was reported by Berry and Rue (1948). Since then, in the Laboratory of Tropical Diseases of the National Institutes of Health, more than 2,000 specimens of P. lapidaria have been exposed to miracidia of S. japonicum. Only 5 have been observed to shed cercariae. From this, it would seem that P. lapidaria is poorly adapted to serve as intermediate host for S. japonicum. However, in the course of this work considerable information has been obtained on the habits and habitats of P. lapidaria, and because it has some potentiality as a vector of S. japonicum this information is of interest. Pomatiopsis lapidaria is broadly adapted as an intermediate host for trematodes. It is known to serve as intermediate host for Paragonimus kellicotti, the North American lung fluke (Ameel 1932); Nudacotyle novicia, found in the bile duct of the meadow mouse (Ameel 1944); and Euhryhelmis monorchis, normally infecting the mink (Ameel 1938). In addition P. lapidaria is known to harbor two cercariae, Cercariae geddesi (Ameel 1939) and Cercariae pomatiopsidis (Stimson 1865 and Ameel 1939), the adults of which are unknown. The range of P. lapidaria is from Minnesota east through Ontario to southern New York. South to Alabama and Texas. Eastern Atlantic Seaboard from Penn-