Published online by Cambridge University Press: 06 April 2009
The ultrastructure and development of Histomonas meleagridis in the reproductive tract of male Heterakis gallinarum has been described. In the testis the protozoon is a relatively large amoeboid organism which lies between the epithelial cells of the testis and the spermatogonia, spermatocytes and spermatids. It is similar in appearance to the invasive stage which is found in the final host and like the invasive stage, it also feeds upon the host cells by phagocytosis. In the vas deferens the protozoon lies between the host cells, where it is much smaller than the stages in the testis but still amoeboid, and inside the cells of the vas deferens.Intracellular stages are much smaller than the other stages, are rounded in appearance and cause little or no damage to the host cell. They are similar to the stages found in oocytes of the female nematode. The possible role of the male nematode in the life cycle of the protozoon is discussed.
I wish to thank Mrs B. Fisher for technical assistance and Mr B. Carter for assistance with the photography.