The structure and development of the protozoonHistomonas meleagridisin the male reproductive tract of its intermediate host,Heterakis gallinarum(Nematoda)

Abstract

The ultrastructure and development ofHistomonas meleagridisin the reproductive tract of maleHeterakis gallinarumhas 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.

ConcurrentCapillariaandHeterakisInfections in Zoo Rock Partridges,Alectoris graeca

“…The most important role of H. gallinarum is its capability of transferring the protozoon Histomonas meleagridis to fowls [9]. A previous report indicated that an outbreak of histomoniasis due to H. meleagridis developed in a chuchar partridge farm in Korea [10].…”

The ambiguous life ofDientamoeba fragilis: the need to investigate current hypotheses on transmission

“…Heterakis ova harbouring Histomonas are able to survive in the soil for up to 2 years (Levine, 1985) (Fig. Several studies exist which describe the relationship between Histomonas and H. gallinarum in greater detail (Lund and Burtner, 1957;Kendall, 1959;Gibbs, 1962;Lee, 1969a;Ruff et al 1970;Lee, 1971;Lund and Chute, 1973). The protozoa are liberated when the helminth ova are ingested by an appropriate host and hatch, releasing both immature worms and the protozoa.…”

Multi-locus sequence typing and plasmid profile characterization of avian pathogenicEscherichia coliassociated with increased mortality in free-range layer flocks

“…Organic production, however, represents new challenges as to controlling biosecurity and pathogens. During freerange production, poultry flocks are exposed to the caecal worm Heterakis gallinarum, the intermediate host of Histomonas meleagridis (Gibbs, 1962;Lee, 1971;McDougald, 2005). As chickens constitute an optimal host for the caecal worm (Lund & Chute, 1974), this underlines the risk of outbreak of histomonosis in freerange layer flocks.…”