Trichomoniasis, avian - UK

International Society for Infectious Diseases
<http://www.isid.org>

Source: Guardian Environment, 13 Sep 2006 [edited]
< http://environment.guardian.co.uk/conservation/story/0,,1871512,00.html >

Hundreds of garden birds are falling victim to a disease that is
spreading across Britain, the Royal Society for the Protection of
Birds (RSPB) warned today. Wildlife veterinary experts were alerted
to the problem after householders reported a number of mystery deaths
in their gardens.

Experts identified the cause as a protozoan parasite that causes the
disease trichomoniasis, which leaves birds so lethargic that they
find it difficult to fly. Death can occur within 3 weeks of infection.

House sparrows, chaffinches and goldfinches are affected, and there
have been outbreaks of the disease in Scotland, Wales, south-western
England and the Midlands. Vets said there was no link to avian flu,
and the parasite posed no risk to human health.

It is thought that the sharing of feeders and baths leads to the
spread of infection between the garden birds. The RSPB has emphasised
the importance of good hygiene, saying birdbaths and feeders should
be regularly washed and moved around the garden to prevent infection.
[Bird feeders have been blamed for the spread of _Escherichia
albertii_, salmonellosis, West Nile virus, & _Mycoplasma
gallisepticum_ among wild birds -- see refs. below.]

Spokesman Andre Farrar said: "It is an unusually large outbreak.
Trichomoniasis usually affects pigeons and doves, but this summer it
seems to have affected finches and house sparrows. There is no human
health risk but, as always when handling birds, people must take
care. We are not sure what the reason is for the high number of
deaths this year, but wildlife vets are investigating." One factor
may be the unusually hot weather in Britain this year, which may have
helped diseases to spread, the spokesman said.

It is thought the cases of trichomoniasis are concentrated in the
Midlands and the south-west of England, with a large number also
reported in Wales. So far, relatively few cases have been found in
the east of England. Vets from the Garden Bird Health Initiative, a
3-year project at the Institute of Zoology, are currently collating
the number of deaths from across the country.

[see images:
House sparrow: http://my.pclink.com/~rlovgren/housespa.jpg
Chaffinch: http://www.rspb.org.uk/Images/chaffinch_male_180_tcm3-67105.jpg
Goldfinch: http://www.hoganphoto.com/Gold_Finch_web.jpg
_Trichomonas gallinae_: http://www.ucm.es/info/parasito/gallinae.jpg]

The following information on trichomoniasis in birds has been
extracted from Merck Veterinary Manual:

Trichomoniasis in domestic fowl, pigeons, doves, and hawks is
characterized, in most cases, by caseous accumulations in the throat
and usually by weight loss. It has been termed "canker," "roup," and,
in hawks, "frounce."

The causative organism is _Trichomonas gallinae_, a flagellated
protozoan that lives in the sinuses, mouth, throat, esophagus, and
other organs. It is more prevalent among domestic pigeons and wild
doves than among domestic fowl, although severe outbreaks have been
reported in chickens and turkeys. Some strains of _T. gallinae_ cause
high mortality in pigeons and doves. Hawks may become diseased after
eating infected birds and commonly show liver lesions, with or
without throat involvement. Pigeons and doves transmit the infection
to their offspring in contaminated pigeon milk. Contaminated water is
probably the most important source of infection for chickens and
turkeys. On trichomoniasis in garden birds, see
<http://www.bto.org/gbw/PDFs/Trichomonas%20advice%20sheet_Aug06.pdf#search=%22trichomoniasis%20finch%22>.