Veterinary Services

A chicken that had been anorexic and diarrhoeic for seven days was submitted for postmortem examination. Another bird had developed diarrhoea and died within 24 hours. Necrotic foci measuring one to two millimetres were found within the liver and larger nodules were found in the lung, distal small intestine and caecum. On section the whole substance of the spleen was necrotic. A Ziehl-Neelsen (ZN) stained smear was positive for acid-fast bacteria confirming a diagnosis of tuberculosis. Tuberculosis, presumed avian, was also diagnosed in a two-year-old layer in which the liver and spleen were greatly enlarged, with multiple pale yellow/cream coalescing foci. Large numbers of acid-fast bacilli consistent with Mycobacterium avium were seen in ZN-stained smears.

Marek’s disease was diagnosed in a yearling chicken showing ill thrift and nervous signs. The other birds in the flock of 30 appeared healthy.

Two turkeys aged 16 weeks were submitted for postmortem examination. One bird was small and had typical postmortem lesions of "round heart disease" or spontaneous cardiomyopathy. The other bird was in good condition and had died from aortic rupture.

An analysis of brachyspira culture results from commercial layers with "wet droppings" was carried out. There were 96 submissions comprising 257 faecal samples during 2006 and early 2007. Negative brachyspira culture results were obtained for 29 percent of the submissions while positive isolation rates were as follows : Brachyspira intermedia 24 percent, B. pilosicoli 25 percent, B. innocens 28 percent, "atypical" Brachyspira species six percent, B. hyodysenteriae four percent and B. alvinipulli one percent. B. intermedia and B. pilosicoli are considered to be pathogenic in poultry, associated with wet droppings and reduced egg yields. The significance of the other isolates in poultry is uncertain. B. hyodysenteriae isolates came from farms in close proximity to pig units.

Wild Birds

A dead adult cormorant (Phalacrocorax carbo) was found attached by a wire to an empty plastic lemonade bottle. A three-pronged fishhook was stuck in the leading edge of one wing, attached to a length of wire that had a further, larger, three-pronged fishhook at the end. The bird had swallowed the larger hook that had become lodged in the oesophageal mucosa midway down the neck. There was a two-centimetre area of necrosis between the right side of the larynx and the base of the tongue and there were areas of necrosis in the oesophageal mucosa. The bird appeared to have died of starvation.

Thirty dead greylag geese (Anser anser) were found in a field in Aberdeenshire. There had been reports of lightning in the area. Examination of five carcases revealed them to be in good body condition but with evidence of extensive internal haemorrhage. It has been suggested that stormy weather can result in the deaths of birds if they become disorientated and fly into the ground, or if they are exposed to abnormally large hailstones.

Deaths in garden birds continued in February, with the commonest cause of death being salmonellosis due to S. Typhimurium phage types 40 and 56 variant.