Protista --> Metamonada --> Parabasalid
Protista --> Metamonada --> Parabasalid
Microscopy, cell cultures, or signs of infection in birds may identify T. gallinae. Excessive swallowing and salivation in birds may be a sign of infection. Under a microscope, parasites are flagellated and appear pear-shaped.
Single Host, Direct Transmission
Trichomonads, flagellate parasites, replicate rapidly by binary fission and do not survive for long outside of their definitive bird hosts. In the wild, parasites spread directly from bird to bird, especially from adult birds to their young or to predatory birds from their prey.
https://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex4444/$file/663-34.pdf?OpenElement
T. gallinae hosts are limited to birds, mostly columbiform birds like pigeons and doves, namely the rock dove Columba livia. Bird species' behavior often aids transmission since the protozoa spread through oral secretions, either by beak contact in mating displays, feeding susceptible young, or, in the case of raptors, feeding on other birds. The parasite causes lesions and a disease known as trichomonosis. The same symptoms as in birds have been observed in dinosaur bones, so it is thought to be an ancient pathogen.
Despite its need for direct transmission between hosts (it does not survive long in the environment), the parasite has managed to spread widely to all geographic areas excluding Antarctica, Greenland, and certain parts of Northern America.