Highlights

• Transmissible viral proventriculitis in broilers
  Work in the United States has recently described a novel birnavirus in association with the condition which has been found to be antigenically and genetically distinct from the birnavirus causing infectious bursal disease (Gumboro disease) however it is not known if a similar cause is implicated in the UK cases.
  
  
• ESBL producing E.coli causing septicaemia in broilers
  The E. coli isolate was confirmed to possess the ESBL (extended spectrum beta lactamase) CTX-M-1. It also possessed several putative virulence genes. ESBL CTX-M-1 and the virulence gene tsh can both be located on plasmids, raising the possibility that they may become co-located on the same plasmid, leading to significant resistance. Thorough terminal hygiene was advised to prevent carry over to the subsequent flock.

Commercial Layers and Layer Breeders

Mycoplasma gallisepticum and Mycoplasma synoviae

Carmarthen investigated an outbreak of respiratory disease affecting fourteen out of a group of 100 eighteen-week-old pullets. Two birds were necropsied at Carmarthen. One bird had a white caseous discharge from the eyes and in the infraorbital sinuses, and yellow liquid and bubbly caecal contents. The other had an increased amount of clear mucus in the infraorbital sinuses and trachea.

Broilers and Broiler Breeders

Transmissible viral proventriculitis

Proventricular lesions and histological correlates similar to those described in cases of so called transmissible viral proventriculitis were seen in a submission of 38 day old broilers with a history of wet litter and poor growth. The principal findings at post mortem examination included bursal atrophy and thickening of the proventricular wall. Incidentally, chronic spondylitis (“spinal abscess”) due to ventral swelling of the spine in the vicinity of the free thoracic vertebra “T4”, was seen in one individual. Histological examination of proventriculus revealed a multifocal lymphocytic proventriculitis with glandular degeneration and ductular hypertrophy and hyperplasia. Work in the United States has recently described a novel birnavirus in association with the condition which has been found to be antigenically and genetically distinct from the birnavirus causing infectious bursal disease (Gumboro disease) however it is not known if a similar cause is implicated in the UK cases.

Avian metapneumovirus

ART/TRT (avian metapneumovirus) challenge was tentatively diagnosed in a flock of 39 day old broilers submitted with a history of sharp 1 per cent increase in mortality, upper respiratory signs and facial swelling. Post mortem examination revealed swelling of the head, creamy exudate within the spongy bones of the skull, tracheal congestion and lung consolidation. Bacterial cultures of lungs and other tissues yielded heavy growth of E. coli. Avian metapneumovirus subtype B was detected on tracheal samples submitted for molecular diagnosis testing (multiplex RT PCR for avian metapneumovirus subtypes A, B, C). However it transpired later that this flock had been vaccinated with subtype B ART vaccine.

Colisepticaemia – ESBL producing E. coli

An increase in death rate in 46 day old broilers was reported in a shed of 22,000 birds. The birds had been receiving antibiotic for seven days. Eight were examined at post-mortem. The predominant findings were pericarditis or perihepatitis and lung congestion. Histopathology revealed severe diffuse septic fibrinous pericarditis, fibrinous hepatitis and acute pneumonia. The E. coli isolate was confirmed to possess the ESBL (extended spectrum beta lactamase) CTX-M-1. It also possessed several putative virulence genes. ESBL CTX-M-1 and the virulence gene tsh can both be located on plasmids, raising the possibility that they may become co-located on the same plasmid, leading to degeneration of a plasmid with avian virulence genes and significant resistance. Thorough terminal hygiene was advised to prevent carry over to the subsequent flock.

Ducks and Geese

Duck virus enteritis

The carcase of an adult female duck was submitted to Winchester with a history of lameness and recumbency together with diarrhoea prior to death. Seven ducks had died from a group of nine, with no deaths having occurred within poultry on the same unit. The liver was friable and pale in colour. A diphtheritic lesion was present on the mucosa of the proximal oesophagus and there was marked diphtheresis in the cloaca. Fine “paintbrush stroke” haemorrhages were present on the surface of the epicardium and there was extensive haemorrhage within the ovary. The clinical signs, history and gross post mortem findings were virtually pathognomonic for the presence of duck viral enteritis, although confirmation of this diagnosis is being pursued through histopathology. Duck viral enteritis is caused by a herpes virus which is often introduced to groups of domestic ducks by in-flying mallards which act as carriers.

Further Reading

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