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Coccidiosis and PRRSV Reported

by 5m Editor
5 November 2008, at 10:05am

UK - The latest Monthly Surveillance Report from the Veterinary Laboratories Agency (VLA) covering pigs during September 2008 includes coccidiosis, PRRSV, salt poisoning and possible cases of PDNS and Osteochondrosis dissecans.

Alimentary Tract Diseases

Coccidiosis was diagnosed as the cause of scour in 15 to 20% of piglets on an 1350 sow indoor weaner-producer. Diarrhoea started between three and 21 days and, within litters, 70 to 80% of pigs were affected from sows of all parities, mortality was low at 3 to 4%. The problem had been present on the unit for several months and injectable Baytril had given a good response in some but not all pigs. The only significant finding in submitted 15-day-old piglets was of abnormal intestinal content in all pigs and gingivitis in one. Intestinal histopathology revealed varying numbers of coccidial stages in the ileum and jejunum and in one piglet, there were coccidia present with morphology typical of Isospora suis. No other neonatal enteropathogens were identified.

Respiratory Diseases

Active PRRSV infection was considered the likely underlying cause of coughing and deaths in three to four-week-old pre-weaned piglets on a 480-sow unit. Fourteen had died from a batch of 50. Sows were vaccinated with live PRRS virus. Three piglets in poor body condition were submitted to Bury and post-mortem examination revealed mixed findings; two had bronchopneumonia and pleurisy, peritonitis and arthritis while a third had diarrhoea due to an enteropathogenic E.coli serotype O147: K89, K88ac (G1253). The same E. coli was isolated from the lungs of the other pigs together with Streptococcus bovis. Both pigs with pneumonia tested positive for European strain PRRSV by PCR, although immunohistochemistry did not detect PRRSV in the lungs. Lesions consistent with greasy pig disease were present on the cheeks of two of the pigs which were not tooth clipped.

Musculoskeletal Diseases

A seven-month-old breeding Red Duroc boar was submitted after showing sudden onset lameness of the left foreleg. The boar was not weight bearing on the limb and was euthanased after failing to respond to treatment. Post mortem examination revealed a severe suppurative arthritis of the left elbow joint and osteomyelitis affecting subchondral bone of one of the distal humeral condyles. The bone affected with osteomyelitis was deep to fissuring and flap formation in articular cartilage consistent with Osteochondrosis dissecans (OCD). Gross lesions consistent with OCD were also present in the right elbow joint, affecting articular cartilage of the humeral condyles. The ends of long bones are predilection sites for haematogenous bacteria to settle out in end arterioles.

Other Diseases

A three-month-old male weaner Landrace x Large White was submitted to Luddington with a history of hematuria. On post mortem examination there was an abscess on the mandible from which an un-typeable Streptococcus suis was isolated. The kidneys were uniformly pale with attenuated cortices and abscessation of the medullae. Histopathology findings on the kidneys indicated severe chronic crescentic glomerular nephritis with a chronic tubulo-interstitial nephritis. These findings were consistent with renal insufficiency/renal failure. Crescentic glomerular nephritis is seen with PDNS and the renal pallor noted during the necropsy would be consistent with this diagnosis. However, abscessation is not a feature of PDNS. The width of the cortex and medulla would suggest that there was some degree of hydronephrosis with resultant compression of the cortex and medulla. Eubacterium suis, often associated with pyelonephritis in pigs, was not isolated in this case.

Nervous Diseases

20 out of a group of 600 four-week-old pigs were showing nervous signs four days post-weaning and two dead pigs were submitted to determine whether the nervous signs were due to salt poisoning or meningitis. Post-mortem examination revealed dark red carcasses with engorged vasculature and dry tacky serosal surfaces. Meningeal congestion was also evident. Histopathological examination demonstrated laminar necrosis and eosinophil infiltration of blood vessels which is pathognomic for salt poisoning in pigs.

Further Reading

- You can view the full report by clicking here.

5m Editor