Veterinary Services

Poultry and game birds

Caecal coccidiosis was diagnosed in four broilers aged two weeks on the basis of gross pathology and the demonstration of oocysts and schizonts in mucosal smears. Coccidiosis was also confirmed in a batch of 100 turkey poults aged four weeks in which 15 died.

Two young turkey poults aged three weeks were submitted from a site where birds were sneezing, had swollen conjunctivae and nasal discharges. Postmortem examination revealed a mucoid conjunctivitis and purulent airsacculitis, and mixed growths of Bordetella avium and Gallibacterium anatis were recovered from the respiratory tract. Additional tests are ongoing to exclude possible involvement of Mycoplasma gallisepticum and avian pneumovirus. Gallibacterium. anatis was also isolated from the sinuses of an adult pheasant with severe bilateral sinusitis. Again, the SAC considered that other agents such as M. gallisepticum or avian pneumovirus were also probably involved.

Coccidiosis was the cause of death of red-legged partridges aged 8 weeks, 13 weeks and 16 weeks, and spironucleosis (hexamitosis) was diagnosed in pheasants and partridges aged seven to ten weeks. In one batch of red-legged partridges the diagnosis of hexamitosis was complicated by crop candidiasis. The affected crops were thickened and the mucosa was overlaid with a white layer of debris. The yeast Candida albicans was cultured. Multiple infections were also diagnosed in pheasants aged ten weeks with increased mortality after their arrival at the release pens. The birds submitted were poorly feathered and had postmortem lesions suggestive of chilling and dehydration. Significant numbers of Spironucleus were found in some birds, one bird had a mycotic airsacculitis and pneumonia from which Aspergillus fumigatus was isolated, and Salmonella Typhimurium phage type 2 was recovered from the viscera of two birds.

Histomoniasis (blackhead) was considered to be the most likely cause of death of an adult peahen that died after showing lethargy and weight loss. The mucosa of both caeca was considerably thickened, with areas of necrosis extending to the serosal surface. Peafowl appear to be more susceptible to histomoniasis than other birds such as domestic fowl.

Pigeons and cage/aviary birds

A young budgerigar was submitted from a breeding collection in which approximately 40 per cent of the birds had died, sometimes after exhibiting weight loss and regurgitation. Severe necrosis of the oesophagus was noted at postmortem examination, and wet preparations from the periphery of the lesions detected significant numbers of motile trichomonad protozoa.

Chlamydiosis was confirmed in a rosella (Platycercus species) found dead approximately six weeks after acquisition from a pet shop. Another rosella from the same source had died, and two canaries were ill. The owner was advised of the potential zoonotic implications and the Divisional Veterinary Manager of the local Animal Health Office informed.

Wild birds

Trichomoniasis of the upper digestive tract was the commonest diagnosis in garden birds in August. A similar trend was observed in 2006 (figure 3 - see top right-hand side). Most cases were seen in greenfinches (Carduelis chloris) and chaffinches (Fringilla coelebs).

Garden bird trichomoniasis was first suspected in a chaffinch in Scotland in April 2005 and has since been seen in many parts of Great Britain. Affected birds appear lethargic, fluffed up and are reluctant to fly. They may show laboured breathing or difficulty in swallowing, and food debris may be seen sticking to the beak. Postmortem examination typically demonstrates ulcerative and/or necrotic lesions in the upper digestive tract. Wet preparations from affected areas of fresh carcases may reveal motile protozoa with the morphology of trichomonads. Similar organisms may be seen at the borders of the lesions on histopathological examination. In conjunction with the Garden Bird Health Initiative, trichomoniasis has been suspected or confirmed in garden birds from 52 sites in Scotland between April 2005 and August 2007, mostly in the south of the country (figure 4 - see top right-hand side). For further information on the Garden Bird health Initiative consult: -http://www.zoo.cam.ac.uk/ioz/projects/garden_bird_health_initiative.htm