Studies on the development and migration of parasitic nematodes

Abstract

This thesis is divided into two parts. The first part is concerned with the developments and migration of Trichosomoides crassicuada, a common parasite of the urinary bladder of rats. The stages in the development of the egg and the experimental data regarding the hatching in various solutions are given. The morphology of the larvae, their migration in the host and the presebce of a stylet in the adult worms are described. The incidence of Trichosomoides crassicuada and its relationshop to the presence of mucoid alouli in the bladder are discussed. Part II describes an attempt to determine the validity of the theory of retrofection and auto-infection of Enterobius vermicularis. Details of various methods used for observing the development and hatching out of the eggs of Enterobius vermicularis are given. Owing to the difficulties experiences in obtaining an adequate amount of material of E. vermicularis, it was decided to determine whether retrofection and auto-infection occur in a closely allied oxyurid Aspiculuris tetraptera of mice. The results of observations on the development and hatching of eggs in various solutions are given. The bionomics of the larvae are described. It was found that the eggs could hatch out on moist cotton-wool swab in the anal opening of a human volunteer and the anal region of mice. Infective eggs are applied in the anal region of clean mice which were imobilised in specially designed cages to prevent their turning. On examination after a few days, adolescent forms were obtained in the colon in four cases. Experiments are now being continued to find out whether mature forms will develop as a result of retrofection. The theory of internal auto-infection is discussed in the light of our own experimental and the data in the literature.