Worcestershire Record No. 21 April 2007 pp. 18-19
TRICHOMONAS GALLINAE – TRICHOMONIASIS IN WILD BIRDS
Compiled by Harry Green.
Late summer 2006 saw outbreaks of this disease – Trichomoniasis - especially amongst greenfinches with many reports both nationally and locally of dead and dying greenfinches in gardens. There have been some reports of dying house sparrows.
Symptoms are difficulty in swallowing, cheese like deposits in mouth lining and down oesophagus and trachea. There are lesions in the mouth and difficulty in swallowing although the birds try to eat. There is also difficulty in breathing. Wild birds are affected by a variety of diseases and deaths of garden birds may be caused by other organisms such as bacteria like Salmonellae which are not uncommon.
Trichomoniasis is caused by a protozoan, a single celled flagellate unicellular organism. Much bigger than a bacterium but still microscopic so definite diagnosis needs laboratory examination.
Trichomonas gallinae is commonly found living in the alimentary tract of pigeons, often without causing disease but it can cause canker in pigeons, and appears to be a severe problem amongst racing pigeons at times.. Recent studies have shown that up to a third of adult wood pigeons in Spain may carry the disease. Transfer of disease to other birds may occur at drinking places. (Villanua et al 2006).
Trichomoniasis is sometimes transferred from pigeons to Birds of Prey when the latter eat the former. There are concerns about the possibility of increased disease rates in raptors.
At garden feeding stations good hygiene important to help curtail the spread of infection which may be transmitted via saliva when birds visit feeders. By keeping feeding stations clean it may be possible to reduce transmission rates although birds also become infected elsewhere.. It seems likely that commonly used drinking places are a likely source of infection so care is required in cleaning bird baths.
There are many species of Trichomonas-like organisms living inside vertebrates and insects, both harmless commensals and harmful parasites.
Generally parasitic Trichomonads cannot survive drying out. Cleaning feeders and bird baths and leaving them dry for a week may help in decreasing spread of disease although natural infections probably occur in the wider environment. Some related Trichomonads do form cysts resistant to drying.
Interestingly the disease seems to affecting birds which habitually live in flocks – greenfinches and sparrows for example – and such gregariousness presumably raised the likelihood of infection between individuals. The disease does not seem to infect tits, blackbirds, and other common birds.
Since last year has appeared quite widely in wild finches and to a lesser extent sparrows.
There are many other diseases of birds caused by bacteria, protozoa and fungi and it is not always possible to know which is infecting a bird dying in your garden without laboratory examination. This is not readily available, although the veterinary service at DEFRA may be able to help.
Bird diseases such as Trichomiasis rarely, if ever, affect people but is sensible to take care when handling bird feeders by good hand washing after tending the feeders, or wearing suitable disposable gloves. From the sources accessed there have been no reports of Trichomonas gallinae infecting humans.
Without clear laboratory identification we are unable to add Trichomonas gallinae to our WBRC database!
This note has been compiled from various sources especially the BTO website (bto.org.uk), BTO press releases, and Cooper & Eley (1979). A web search will give you a great deal more information as the disease is of veterinary concern for some birds.
|COOPER JE & ELEY JT (EDS). 1979. First aid and care of wild birds. David & Charles: Newton Abbot.|
|VILLANÚA, D, HÖFLE U, PÉREZ-RODRÉGUEZ L, & GORTÁZAR C 2006. Trichomonas
gallinae in wintering Common Wood Pigeons Columba palumbus in
Spain. Ibis 148:641-648.|
|WBRC Home||Worcs Record Listing by Issue||Worcs Record Listing by Subject|