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VLA: Respiratory Disease Outbreak in Breeding Herd

by 5m Editor
4 November 2009, at 7:09am

UK - According to Defra's VLA Monthly Scanning Surveillance Report for September, two live piglets were examined in Preston to confirm the outbreak of a respiratory disease in a breeding herd.

Alimentary tract diseases

Salmonellosis

Four live pigs were submitted to Bury from an indoor 250-sow breeder finisher unit where wasting was affecting 5% of 600 pigs aged six to 10-weeks-old with approximately 3% post weaning mortality. Piglets were vaccinated for PCV2 and Mycoplasma hyopneumoniae. Three of the four submitted pigs had diarrhoea, two of these had severe typhlocolitis and one had thickening and corrugation of the ileum. A multiple aetiology was identified with porcine intestinal adenomatosis confirmed in the pig with ileal thickening, and Salmonella Typhimurium phage type U288 and Brachyspira pilosicoli being isolated from the large intestines of all three scouring pigs. PCV2 associated disease was not identified.

Salmonellosis due to Salmonella Typhimurium phage type U288 was diagnosed as the cause of weight loss and occasional scour in eight-week-old pigs from an outdoor rearing site. Twenty-five of 1,100 pigs had died. Pigs were vaccinated for PRRSV and PCV2. Two dead pigs were submitted both of which had a necrotic typhlocolitis which yielded the Salmonella organisms.

Another outbreak of salmonellosis was diagnosed on an indoor 540-sow unit rearing pigs to 35 kgs. From one shed of 1000 rearing pigs, 55 deaths were recorded over a nine week period with two to three wasted pigs being found dead each morning. Rearing pigs were vaccinated for Streptococcus suis and PCV2. Two dead pigs were submitted, both of which had a severe typhlocolitis from which Salmonella Typhimurium phage type U288 was isolated and no other enteropathogens or PRRSV were identified. Histopathology did not reveal involvement of PIA or PCV2.

Sutton Bonnington isolated Salmonella Typhimurium PT 193 from pooled faeces submitted from 14-week-old rearing pigs. The diarrhoea had started in 25% of a group of 71 on the morning of submission. There had been no deaths.

Respiratory Diseases

Mycoplasmosis

Two live piglets aged 6 weeks were submitted to Preston to investigate an outbreak of respiratory disease in a breeding herd. Coughing was initially observed in adults together with an occasional animal with a mucopurulent nasal discharge. Disease then progressed to affect most litters typically from around 4 weeks of age onwards – clinical signs in younger pigs included coughing, increased respiratory rate and a “thumping“ respiration in some animals. There was gross and histological evidence of severe chronic proliferative bronchointerstitial pneumonia in both animals submitted. No bacteria were recovered (possibly due to prior antibiotic therapy), but Streptococcus suis was detected in lungs from both pigs by DGGE. Tests for PRRS and SI viruses were all negative.

Other diseases

Erysipelas

Bury investigated an outbreak of swine erysipelas which presented as sudden death of approximately ten of 1000 pigs on the day of weaning. Pigs died rapidly after being seen panting, with reddened skin and a few pigs were seen with diamond-shaped skin lesions. The pre farrowing erysipelas booster for the gilts, from which these pigs were weaned, had been inadvertently omitted. Other ages of pig were reported to be well, which included sows, with numbers born live remaining good.

Neurological Diseases

Streptococcus suis type 2

Streptococcus suis 2 infection was responsible for eight sudden deaths of nine-week-old pigs from a group of 600 on a 2300 pig indoor nursery finisher unit containing pigs from two sources where only one source was affected at the time of submission. Some coughing and joint swelling was reported in the group. Three dead pigs were submitted to Bury with gross lesions suggestive of a septicaemia and, in one, a fibrinous exudate was present over the meninges. Meningeal smears from all three pigs tested positive for S.suis 2 and the organism was isolated from meninges and internal viscera. No PRRSV involvement was identified. These pigs had been vaccinated with Streptococcus suis 2 vaccine.

Further Reading

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

5m Editor