Veterinary Services

Poultry

Acute Marek’s disease was diagnosed in a nine-month-old Sussex pullet submitted for necropsy after the bird lost weight and died. Other birds in the same batch were also thin. The spleen was considerablely enlarged and the wall of the proventriculus thickened.  There were multiple nodules on the heart, liver and serosa of the intestine. Histopathology demonstrated an infiltration of pleomorphic neoplastic cells of the lymphoid series, consistent with a diagnosis of acute Marek’s disease. No infiltration of the peripheral nerves was found.

Ayr received sequential submissions of broilers from a flock experiencing higher than expected mortality. “Normal” causes of mortality were found: yolk sac infections, non-starters and kidney failure were detected in birds in the first week, followed by heart failure, broiler ascites and E coli septicaemia in the second week. Culling due to poor growth was also higher than normal. Subsequently analysis of the feed revealed errors in the diet formulation.

Two, eight-week-old turkey poults were submitted from a group of 70 birds because some were undersized. The crop of one bird submitted was empty, with thickened whitish mucosa from which heavy growths of yeasts were isolated. Histopathology showed widespread invasion of the crop mucosa with pseudohyphae consistent with those of Candida albicans. The second bird had gross lesions of trauma, but histopathology revealed multifocal areas of acute pneumonia.  Mycoplasma gallisepticum was isolated from subsequent submissions from the same group. Candidiasis and mycoplasmosis are not uncommon in small flocks of turkeys.

Racing pigeons

Salmonella Typhimurium DT2 was isolated from the liver, spleen and intestine of an adult racing pigeon that lost weight, became moribund and died. Faecal soiling of the vent and feet was noted, and hepatomegaly and splenomegaly were found at necropsy. Deaths also occurred in young late-bred pigeons, including the progeny of this bird. The same organism was recovered from a racing pigeon from a different loft, where two of 20 birds had died. The Divisional Veterinary Manager of the local Animal Health Office was informed of these isolations as required under the Zoonoses Order 1989.

Cage and aviary birds

The carcase of an African grey parrot aged approximately 20 weeks was submitted. The bird was thin, with very little food in the digestive tract and collapsed intestines. The bursa of Fabricius was small, and the bone marrow was red and watery, with very few cells of the granulocyte series present. No significant bacteria or fungi were isolated.  SAC suspected underlying infection with psittacine beak and feather disease virus.  Infection with this circovirus can cause bursal atrophy and bone marrow suppression in birds of this age.

Brachyspira hyodysenteriae was isolated from the intestinal contents of a rhea which presented with diarrhoea. This organism has been associated with an ulcerative typhilitis in rheas elsewhere.

Wild birds

Traumatic injuries were found in several wild birds examined in October, including a mute swan (Cygnus olor), redwing (Turdus iliacus), barn owl (Tyto alba), sparrowhawk (Accipiter nisus) and skylark (Alauda arvensis).

Small pieces of lead were found in the gizzard of a mute swan found moribund on a loch used by the general public for recreational purposes. The bird was in moderate to poor condition, and the oesophagus and proventriculus were impacted by fibrous material. Lead poisoning associated with lost or discarded fishing weights caused the deaths of many birds on this site several years ago.

A  buzzard (Buteo buteo) was found dead near a sporting estate, raising concerns that illegal persecution could have been involved. Postmortem examination showed that the bird was thin, with a severe necrotising cellulitis affected the carpal region of the wing. Mixed growths of Staphylococcus aureus, Clostridium perfringens and Clostridium sordellii were isolated from the affected tissues. No gross evidence of poisoning or of gunshot injuries was found. In another unrelated incident parasitism was diagnosed in a thin buzzard.  It had a severe necrotic stomatitis associated with hairworms (Eucoleus species).  Also substantial numbers of large roundworms (Porrocaecum species) distended the proventriculus, gizzard and upper intestine (figure 4 - see top right-hand side).