[4] H. gallinarum has a direct lifecycle involving birds such as chickens, turkeys, ducks, geese, grouse, guineafowl, partridges, pheasants, and quails as definitive hosts.

Upon ingestion by a host, the embryonated eggs hatch into second-stage juveniles in the gizzard or duodenum, and are passed to the cecum.

Earthworms and houseflies are considered paratenic hosts, as they can ingest the egg in feces and a juvenile may hatch in tissues, which stays dormant until eaten by birds.

[4] H. gallinarum is geographically distributed worldwide, commonly found in chickens, domesticated turkeys, and many other species of fowl, primarily of poultry.

Their eggs are found to live for years in soil making it difficult to eliminate H. gallinarum from a domestic flock.

However, H. gallinarum plays the role of carrier in the lifecycle of Histomonas meleagridis, the causal pathogen of enterohepatitis "blackhead" of turkeys.

[6] Heavy infection in pheasants indicated gross lesions characterized by congestion, thickening, petechial haemorrhages of the mucosa, intussusception, and nodules in the cecal wall.