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New IB Strain and Losses in Christmas Turkeys

by 5m Editor
2 December 2008, at 8:05am

UK - The Monthly Surveillance Report from the Veterinary Laboratories Agency (VLA) for October 2008 highlights a further case of infectious bronchitis (IB) caused by the imported QX virus strain and losses of turkeys destined for the Christmas market from mycoplasma, erysipelas and blackhead.

Femoral Head Necrosis

Penrith diagnosed femoral head necrosis following post-mortem examination of ten, 48-day-old broiler chickens from a flock with a history of birds going off their legs and increased mortality. Staphylococcus aureus was isolated from five of the six femoral heads cultured, while E.coli was isolated in the sixth.

Erysipelas

RVC diagnosed septicaemia caused by Erysipelothrix rhusiopathiae as the cause of death in five turkeys out of 520 that were due to be slaughtered at the beginning of December. The birds were being found dead with no premonitory signs. Post mortem findings included petechial haemorrhages in the heart and pericardium, enlargement and congestion of the spleen, and in one case haemorrhagic enteritis was evident. Gram-positive rods were seen on smears from heart blood. The organism was isolated from a range of tissues in two of the birds, including a hock joint and bone marrow.

Spirochaetal Enteritis

Winchester investigated poor egg production and abnormal droppings affecting a large commercial layer unit. The possibility of intestinal spirochaetosis was suspected, and following necropsy of eight affected birds, Brachyspira intermedia, B. pilosicoli and B. innocens were isolated. B. intermedia and B. pilosicoli are recognised intestinal pathogens in layers and the clinical signs reported were consistent with this finding.

QX Strain of Infectious Bronchitis Virus (IBV)

In early September, respiratory signs in 5 of 17 chickens in a hobby flock prompted submission of two Sussex birds to Truro for post-mortem. Both birds showed evidence of a conjunctivitis, tracheitis and nephropathy at post mortem examination. Subsequent testing revealed IBV that demonstrated an antigenic relationship to the QX strain in one-way HI serology. This case represents the third isolation of IBV QX from backyard chickens in Great Britain over the past 14 months which has resulted from VLA scanning surveillance activities.

Blackhead

Histomoniasis was diagnosed on four separate occasions by Langford typically affecting growing turkey poults. Birds showed a range of signs including some more suggestive of respiratory problems but at post mortem in all cases there were the typical lesions of hepatic necrosis. Histological examination of these lesions revealed granulomatous necrotising hepatitis with invasion of cells by rounded bodies typical of histomoniasis.

Mycoplasmosis

Shrewsbury investigated the deaths of 10 birds from a group of 120, which had been on the premises for 2-3 weeks. They were eight week old birds for the Christmas market. The birds apparently had not looked particularly well when purchased. A live and dead bird were submitted for examination and respiratory disease was evident with the live bird mouth breathing and it had a markedly swollen head with distension of the sinuses, the left eye was closed and there was swelling of the eyelids. Gross signs of sinusitis were present and denaturing gel electrophoresis (DGGE) indicated the presence of Mycoplasma gallisepticum, a recognised primary pathogen.

Gamebirds

Deaths in thirty, 20-week-old pheasants from a flock of several thousand were reported. The birds were losing weight and going off food and water, and then dying quickly. Seven birds were submitted to Penrith and examination of the respiratory system revealed that all had significant gapeworm infestations. There was also significant enteric parasitism.