Development of Eye Flukes of Fishes in the Lenses of Frogs, Turtles, Birds, and Mammals

Abstract

About a century after von Nordmann (1832) first found strigeid metacercariae occurring in the eyes of fishes, La Rue, Butler, and Berkhout (1926) demonstrated that they were common habitats for species of these larval trematodes. Strigeid metacercariae have also been reported from the eyes of certain amphibians (Kelley, 1934). Various parts of the eye may be parasitized, depending upon the species of worm. This paper deals with metacercariae of the genus Diplostomulum that live only in the cortex of the lens, and is a report of experiments in which it has been found that worms ordinarily developing in the eyes of fishes, and in many cases causing complete blindness, will grow in the lenses of both coldand warm-blooded animals representing four other classes of vertebrates. The experiments were performed as an outgrowth of studies on the life history and control of eye flukes in the New Jersey State Fish Hatchery at Hackettstown. The trematodes represented at the Hatchery appear to resemble both Diplostomum flexicaudum and D. indistincturn (Ferguson and Hayford, 1941), and studies now in progress may show that these recognized forms are variants of a single species. All cercariae used in exposure experiments resembled closely, as far as morphology and behavior were concerned, the cercariae of D. flexicaudum (Cort and Brooks, 1928).