Filarial Worms (Diplotriaena and Serratospiculum spp.):

Adult filarial roundworms are long, thin nematodes measuring several cms. in length depending upon the species. They occur mainly in the air sacs or thoracic and abdominal cavities of a wide variety of birds. The larvae of many species, known as microfilariae, occur in the blood. Diplotriaena is common in passerines, and Serratospiculum is frequently encountered in various species of birds of prey. The life cycle of filarial worms, although well understood in man and some mammals, is mainly unknown in birds. It is very likely, however, that in most cases microfilariae in the blood are taken up by blood-sucking insects such as midges or "punkies" (Culicoides) and buffalo gnats or black flies (Simuliurn). They undergo development in the insect intermediate host, and eventually infective larvae are introduced back into the blood stream of the bird when the insect bites. The larvae in the bird develop into the mature adult worms, which produce numerous eggs; these in turn give rise to the larvae (microfilariae) which enter the blood.

There is evidence that the life cycle of at least one species of Serratospiculum, (S. tendo of birds of prey), is not transmitted by biting flies. The hosts become infected by eating certain insects such as those in the order Orthoptera, for example, locusts (Locusta migratoria) which have ingested ova passed by infested birds. Pneumonia, inflammation of the air sacs and fits have all been attributed to filarial worms, but it is likely that they are harmless except in heavy infestations.

Treatment and control:
No satisfactory treatment is known at the time of this writing. If there is evidence from the results of postmortem examination or microscopical examination of blood, that the parasites are troublesome in an aviary, then steps should be taken to control possible insect hosts by the use of insecticides. Transferring birds to an indoor aviary may also be necessary if Culicoides midges are suspected carriers, because they are so small that they can easily penetrate ordinary mosquito netting.


E-Mail: berniehansen@sympatico.ca



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Hamilton & District Budgerigar Society Inc.