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Chinese IB Virus Found in UK Backyard Flock

by 5m Editor
5 August 2009, at 11:01am

UK - The <em>Monthly Scanning Surveillance Report</em> for June 2009 from the Veterinary Laboratories Agency (VLA) highlights a further outbreak of QX strain infectious bronchitis (IB) in rare-breed chickens, and several health issues in game birds.

Highlights

Further outbreak of QX strain infectious bronchitis (IB) in chickens – This strain of IB virus is believed to have been imported into GB having originated in China. This outbreak provides further evidence that the backyard poultry population can act as a reservoir of infection.

Disease outbreaks in game birds associated with coccidiosis, coronavirus, rotavirus, Salmonellosis and Spironucleosis – The seasonally associated increase in diagnostic submissions has identified a familiar spectrum of diseases including Salmonella Kottbus and S. Binza.

Commercial Layers and Layer Breeders

Enterococcus faecalis

Septic arthritis localised in the hock and knee joints was found the cause of lameness in three flocks of layer pullets aged between 20 and 28 days old. Moderate growth of Enterococcus faecalis was obtained from affected joints in all three submissions.

Erysipelas

Erysipelothrix rhusiopathiae septicaemia was diagnosed in two flocks of 54- and 55 week-old free-range layers with a history of ongoing mortality from around 40 weeks. Egg production was not significantly affected. The organism was recovered in heavy pure growths from cultures of liver, spleen and endocardial vegetations.

Broilers and Broiler Breeders

Encephalomalacia

Vitamin E deficiency-encephalomalacia, currently a rare condition in domestic poultry, was diagnosed in a flock of 1,300 25-day-old free-range organic broilers. A history of nervous signs developing two days prior death and clinical signs including ataxia, lateral recumbency and tremors. At post mortem examination, varying degrees of congestion and petechiation of the cerebellum were noted. Histological examination of brains revealed large areas of necrosis in the cerebellar folia with local haemorrhages and prominent hyaline fibrin microthrombi in blood vessels. No other part of the brain was affected.

Rickets

Rickets was diagnosed in a flock of 4,500, 20 day-old free-range organic broilers with a history of recent onset of lameness. Findings at post mortem examination were of poor bone strength affecting leg bones in particular, and slight enlargement of parathyroid glands. Histological examination of undecalcified sections of growth plates stained by Von Kossa's method confirmed mild osteodystrophic changes and patchy mineralization failure consistent with rickets.

Backyard Flocks

QX strain infectious bronchitis virus (IBV)

Winchester diagnosed the QX strain of IBV as the cause of an outbreak of respiratory disease among approximately 1,200 rare breed chickens. An estimated 40 per cent of a group of 500 young birds were affected by respiratory disease manifested principally as sneezing. Post-mortem examination revealed inflammation of the tracheal mucosa with patchy congestion of the lungs. This strain of IBV has been isolated previously from backyard chickens (Veterinary Record (2008), 162, 99-100.)

Game Birds

Coccidiosis

Coccidiosis was diagnosed in six-week-old red-legged partridges submitted to Penrith. The birds appeared thin and dull before death but there was no obvious diarrhoea. In the two birds submitted, profuse numbers of coccidial oocysts were found in bright yellow, necrotic cores found in the caeca.

Coccidiosis was also diagnosed in a separate submission of for-week-old red-legged partridges. In this case, the parasite was found in the small intestine however there were no obvious gross lesions.

Coronavirus

Deaths in 40 of 80 breeding pheasants were investigated and two 12-month-old birds were submitted. The principal finding at post-mortem was pale mottled kidneys. Histopathological examination of the kidneys revealed changes consistent with those described in coronavirus nephritis of pheasants. This disease had been diagnosed the previous year in breeding birds in the flock and it was noteworthy that a few cock birds had been retained from the previous year.

Rotavirus

Five, 4- to 7-day-old pheasant poult carcasses were submitted to Sutton Bonnington. Approximately 200 of 800 birds were presenting with malaise, ill thrift, recumbency and death. At post-mortem, the caeca of all birds were distended with frothy, wet, mustard-yellow content. Rotavirus was detected in all samples by PAGE.

Salmonellosis

A batch of eight-day-old pheasant chicks was submitted to Preston to investigate a rapid increase in mortality (100 out of 300 dead) after five days of age. All birds examined showed gross evidence of enteritis. Laboratory tests confirmed the presence of Salmonella Kottbus in three and rotavirus in four out of five birds examined.

Winchester diagnosed enteritis associated with Salmonella Binza as the cause of death of 1,000 chicks out of a group of 10,000 six-day-old partridge chicks.

Spironucleosis

Winchester diagnosed Spironucelosis (hexamita infection) as the cause of runny, yellow, frothy droppings affecting 10 per cent of a group of 4,000 birds with 50 deaths.

Further Reading

- You can view the full report by clicking here.

Further Reading

- Find out more information on the diseases mentioned in this article by clicking here.