Transplantation of a Monogenetic Trematode, Polystomoides sp., to the Chick Chorioallantois

Abstract

A monogenetic trematode, Polystomoides sp., from the oral mucosa of the midwestern painted turtle, Chrysemys picta bellei, has survived on the chick chorioallantois for up to 7 days. Fortysix of 131 Polystomoides sp. transplanted to the chorioallantoic membranes of 66 9to 13-day-old chick embryos maintained at 30 C, were recovered live 1 to 7 days after transplantation. Ten additional worms were recovered dead on the shell or chorioallantois. Thirty-two eggs were either contaminated or dead at the time of worm recovery. Flukes removed from the chorioallantois 1 to 7 days postimplantation were as active as those from the oral mucosa. Chorioallantois specimens contain diverticulate ceca with dark-brown granular material suggesting that they ingest and utilize blood from the vascular chorioallantoic membrane. Although a digenetic trematode, Philophthalmus hegeneri Penner and Fried, 1963, has been grown on the chick chorioallantois (Fried, 1962), there are no published reports on the maintenance of monogenetic trematodes in this site. The monogenetic trematode, Polystomoides sp., from the oral mucosa of naturally infected midwestern painted turtles, Chrysemys picta bellei Gray, has been transplanted to the chick chorioallantois (Fried, 1965). The purpose of this paper is to present the details of this study. MATERIALS AND METHODS Chrysemys picta belli, obtained from a commercial dealer in Minnesota (J. R. Schettle Frog Farm, Inc., Route 1, Stillwater), were decapitated and the heads cut midsagittally to expose the oral mucosa. Polystomoides were removed from the oral mucosa of infected turtles (Figs. 2, 3) with dissecting needles and transferred through one to three changes of sterile Ringer's solution. Fertile white leghorn hens' eggs were incubated at 37 to 38 C, for 9 to 13 days. Sterilization procedures, methods used to operate on eggs and to implant Polystomoides on chorioallantoic membranes were as previously described for eye flukes (Fried, 1962). Polystonwoides were maintained on chorioallantoic membranes for 1 to 7 days postimplantation at 30 ? 1 C (Figs. 1, 7-9). Eggs were examined as previously described (Fried, 1962). Parasites were observed and photographed on the chorioallantois, lifted from the membrane with watchmaker's forceps, and placed in Ringer's. Polystomoides flattened on slides with moderate cover slip pressure were studied and Received for publication 24 March 1965. * Supported in part by a research grant from the Advanced Studies and Research Fund of Lafayette College and in part by NIH Grant AI03443. photographed live. Flattened specimens were also fixed in AFA, stained with Gower's (1939) carmine, measured, and photographed. Polystomoides from the oral mucosa were examined, fixed, stained, measured, and photographed in a similar manner. One hundred thirty-one worms were placed on the chorioallantoic membranes of 66 eggs. One to four flukes were used per egg, and the membranes were examined 1 to 7 days later. Fifteen Polystomoides maintained individually in 10 ml Ringer's solution at 30 ? 1 C and at room temperature (20 to 24 C) were used to determine the survival time of Polystomoides in Ringer's.