Alimentary Tract Diseases

Salmonellosis

Bury diagnosed salmonellosis as the cause of approximately 30 deaths from a group of 1,300 10-week-old growers in straw yards. The deaths had occurred since moving to the yards a week earlier. Several other pigs were seen looking lean and depressed with some scour.

Necropsy of two of the affected pigs revealed marked thickening and diphtheresis of the distal half of the small intestine (see figure) with localised peritonitis and coils of intestine loosely adherent to each other. Similar lesions extended into the caecum and proximal colon. PRRS virus was identified by PCR in the spleen of both pigs suggesting that PRRSV challenge on entry to the straw yards had predisposed to the salmonellosis. Appropriate advice on disease control and public health was given.

Lesions affecting the distal small intestine of a 10-week-old pig with Salmonellosis

Respiratory Diseases

Actinobacillus pleuropneumoniae

Shrewsbury diagnosed pneumonia caused by Actinobacillus pleuropneumoniae (App) as the cause of death of ten pigs from a total of 20 affected animals, part of a larger group of 500. There was no evidence for viral infection, including influenza and PRRS.

Preston also isolated the same organism along with other pathogens from cases of respiratory disease. Sixteen out of 25 10- to 16-week-old pigs were affected with six deaths. Necropsy of two older animals revealed gross evidence of chronic bronchointerstitial pneumonia whilst the youngest pig had a subacute polyarthritis and a severe chronic vegetative endocarditis. Lung lesions yielded Pasteurella multocida and Actinobacillus pleuropneumoniae whilst the heart valve lesions yielded Streptococcus suis type 1. In addition one of the pneumonic lungs was also positive for Mycoplasma hyopneumoniae by DGGE. There was no histological evidence of PMWS in either of the two older animals.

Swine influenza

Bury diagnosed influenza in two culled 14-week-old pigs submitted from an indoor nursery finisher unit on which a low-grade cough was reported in approximately 60 per cent of 400 pigs. Mortality had been low with five pigs dying and pigs were generally bright and eating. The pigs submitted had cranioventral pulmonary consolidation and swine influenza virus (not pandemic H1N1 09) was identified by PCR, histopathology revealed a bronchointerstitial pneumonia with bronchiolitis, consistent with swine influenza virus infection. The causative virus is being typed.

Streptococcus suis

Sutton Bonnington isolated Streptococcus suis type 8 from the lung of one of two piglets aged five to six weeks, submitted to investigate ongoing problems of pneumonia and scour a week after weaning at three to four weeks of age. Active PCV- 2 infection (PMWS) was also confirmed and was likely to have predisposed to the infection.

Neurological Diseases

Streptococcus suis

Six eight-week-old housed pigs died over a weekend from a group of 300. Clinical signs were of sudden collapse, lateral recumbency and paddling. One dead and one live pig were submitted to bury for necropsy, the live pig was pyrexic and showing tremors and hyperaesthesia. Necropsy revealed Streptococcus suis 2, and Streptococcus suis type 7 isolated from the meninges of live and dead pig respectively. In both pigs, there were severe bronchopneumonia from which Pasteurella multocida was isolated; however no evidence of underlying viral infection (PRRSV, swine influenza, PCV-2) was identified. The live pig was also scouring and anaemic. No enteropathogens were identified but the pig was found to be iron deficient with a serum iron concentration of 4.8µmol/l, (reference range 11–32µmol/l).

Langford also confirmed Streptococcus suis type two meningitis in two pigs from different finishing herds. In one of these, approximately six-week-old pigs were affected, with sudden death as the main clinical sign. On the other unit, acute onset neurological signs were seen in 13-week-old animals in which four out of a group of 20 were said to be affected.

Glassers Disease

Sutton Bonnington diagnosed Glasser’s disease in a 10-week-old pig from a rearing unit which had experienced five deaths. Pigs had arrived on site at four weeks of age and in the last three batches, nervous signs had been observed, which included convulsions, nystagmus and recumbency.

Necropsy findings included polyserositis, fibrinous pericarditis and an excess of cerebrospinal fluid with engorgement of meningeal vessels. Haemophilus parasuis was isolated from the brain, which was consistent with the nervous signs and polyserositis. S. kedougou was isolated from the intestinal contents. This Salmonella isolate showed antimicrobial resistance to sulphonamides, tetracycline and trimethoprim/Sulphamethoxazole. A review of the in-feed medication with Trimethoprim was recommended.

Further Reading

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Further Reading

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Further Reading

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Find out more information on PMWS by clicking here.