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SIR, – Infection with Salmonella enterica serotype Typhimurium is a common cause of thickening, ulceration and necrosis of the oesophagus and crop of wild finches of the family Fringillidae (Pennycott and others 1998), with most cases occurring between January and April (Pennycott and others 2002). Profuse growths of S Typhimurium can be cultured from the viscera of affected birds.
Over the past year we have encountered several instances of deaths in chaffinches (Fringilla coelebs) and greenfinches (Carduelis chloris) in which a necrotic ingluvitis was apparent at postmortem examination, similar to that seen in finches with salmonellosis but from which no significant bacteria or yeasts could be cultured. Affected birds included a greenfinch in October 2004, a chaffinch in April 2005, two greenfinches in June 2005, two chaffinches and a greenfinch in July 2005, and four greenfinches and a chaffinch in August 2005. The birds were submitted from eight sites in Scotland and England.
Gross lesions on the mucosa of the oesophagus and crop varied from small, focal, yellow nodules, 2 to 4 mm in diameter, to a more diffuse yellow-orange thickening of the mucosa, to more severe masses of yellow, orange or white debris overlying areas of deep ulceration and causing partial or complete obstruction of the upper digestive tract (Fig 1). Changes were often visible from the serosal surface of affected organs, and sometimes even through the skin of the bird. A small caseous nodule was noted in the oropharynx of one bird.
Histopathological examination of the oesophagus and crop of three chaffinches from two locations showed a severe ulcerative oesophagitis and ingluvitis, with structures suspected to be trichomonads close to the deep borders of the lesions. In addition, wet preparations from the borders of the necrotic areas in the crop of a greenfinch demonstrated large numbers of motile protozoa, possibly trichomonads.
Trichomoniosis of the upper digestive tract is a common problem in pigeons and doves of the order Columbiformes (Chitty 2003), in birds of prey of the order Falconiformes (Samour and others 1995), and in budgerigars (Melopsittacus undulatus) (Baker 1986). Trichomonads have also been demonstrated in the oesophagus and crop of domestic fowl (Gallus gallus domesticus) and pheasants (Phasianus colchicus) (Willoughby and others 1995, Pennycott 1998). However, to the best of our knowledge, this is the first time that trichomonads or similar organisms have been associated with necrotic ingluvitis in wild birds of the order Passeriformes, family Fringillidae, in the UK.
It is tempting to speculate that the finches may have acquired the organisms from other wild birds such as collared doves (Streptopelia decaocto), possibly at feeding stations or water baths provided by the general public, but evidence to support such a hypothesis has yet to be found. We have recently begun a national investigation (the Garden Bird Health initiative) into garden bird health and feeding practices (Cunningham and others 2005), and would be very interested to hear if other colleagues have encountered this condition in garden finches.
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