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Atypical Case of PCV2 Reported

by 5m Editor
10 February 2009, at 9:11am

UK - The December 2008 Monthly Disease Surveillance Report from the Veterinary Laboratories Agency includes an unusual case of porcine circovirus disease (PCV2), which had affected the liver and caused jaundice in a single pig six months old.

Alimentary Tract Diseases

Brachyspira pilosicoli

The problem of a low grade scour spreading through a group of approximately 300, 14-week-old growing pigs was investigated by Langford. It was reported that at least 40 were affected. Brachyspira pilosicoli was isolated from a typical faecal sample.

On another unit, swine dysentery was confirmed following the isolation of Brachyspira hyodysenteriae from a faecal sample collected from 16-week old pigs with diarrhoea. Twelve out of 50, 16-week-old pigs were said to be affected.

Colibacillosis

Enteric colibacillosis exacerbated by environmental factors was suspected to be the cause of wasting and scour affecting 200 of 1,600 six-week-old pigs in outdoor tents in groups of 90, the scour was seen from four and a half weeks of age and ten deaths occurred. Four live and two dead pigs were submitted to Bury; all were hairy and dehydrated and in poor or very poor body condition. Three of the pigs had gross evidence of enteric disease and profuse growths of a variety of enteropathogenic E.coli were isolated. The body condition of the pigs suggested that problems began soon after weaning and environmental factors such as chilling may have played a role in predisposing to, or exacerbating, disease. No involvement of PRRSV or PCV-2 was identified.

Porcine proliferative enteropathy

Bury diagnosed porcine proliferative enteropathy as the cause of wasting from 17 weeks old onwards in a 550-sow indoor breeder finisher unit. Approximately eight pigs were affected in each batch of 400, and about half of these died. Post-mortem examination of six affected pigs revealed thickening, reddening and corrugation of the distal third of the small intestine of varying severity and intracellular acid-fast curved rods were visible in MZN-stained smears from the small intestinal mucosa, consistent with PPE. No evidence of PCV2-associated disease was found.

Atypical PCV-2 associated disease

An unusual manifestation of PCV-2 infection was described by Winchester affecting a single six-month-old pig on an outdoor unit. It was profoundly jaundiced with an enlarged orange-coloured liver. Immunohistochemistry confirmed severe and widespread PCV-2 infection of hepatocytes, the jaundice thought to be due to hepatocyte swelling and necrosis with mechanical obstruction of normal bile flow.

Respiratory Diseases

Haemophilus parasuis and PRRS

A single fresh pluck was submitted to investigate coughing in growers arriving on a rearing unit two to three weeks earlier; 10 had died from a group of 200. The submitted pluck showed a lobar pneumonia with generalised fibrinous pleurisy and pericarditis suggestive of Glasser’s disease, which was confirmed by the isolation of Haemophilus parasuis. In addition, PRRS virus was detected by PCR in lung tissue and histopathology revealed a subacute severe diffuse bronchointerstitial pneumonia with alveolar necrosis and type 2-pneumocyte hyperplasia suggesting that the PRRSV was significant in the respiratory disease.

Other Diseases

Erysipelas

Three lactating gilts in a batch of 120 on an outdoor breeding herd showed malaise and diamond-like skin lesions which responded well to antibiotic treatment. Most of the piglets in two of these litters died rapidly and one two-week-old pig was submitted to Bury for post-mortem. The necropsy revealed marked purpling of the skin of the snout and ear extremities, subtle multifocal pinpoint haemorrhages in the subcutis of the abdomen, a mottled slightly enlarged liver and fibrin stranding in the peritoneal cavity. Pure growths of Erysipelothrix rhusiopathiae were isolated from the liver and spleen consistent with swine erysipelas.

Streptococcus dysgalactiae equisimilis

Swollen joints and fading pigs at 17 to 20-days-old was described in an unspecified number of litters on an outdoor breeding unit. Three dead pigs were submitted to Bury and post mortem revealed all to have arthritis with excess turbid synovial fluid. One pig also had omphalitis and vegetative endocarditis affecting the left atrioventricular valve. Streptococcus dysgalactiae equisimilis was isolated in pure and profuse growth from lesions and internal sites.

Further Reading

- You can view the full report by clicking here.
- Find out more information on the diseases mentioned in this article by clicking here.

5m Editor