Veterinary Services

Meningitis due to Streptococcus suis serotype 2 infection was diagnosed on three unrelated units. In one case a fourteen-week-old boar had intense meningeal congestion and greyish opacity of the meninges. Streptococcus suis serotype 2 was isolated in culture from the lung and brain. In another finishing herd Streptococcus suis serotype 2 meningitis and septicaemia was diagnosed in a ten-week-old gilt, which had cloudiness of the meninges over the cerebrum and cerebellum. S. suis serotype 2 meningitis was also diagnosed in thirteen-week-old pigs from the same herd which had been found dead. On the third unit ten deaths occurred in the six weeks  following weaning. The pigs were either found dead or showed signs of inco-ordination. Streptococcus suis serotype 2 was isolated from the brain.

Three abortions occurred over a two to three week period in an outdoor herd. All were about two to three weeks premature. One litter of piglets  that died at varying stages of gestation was submitted. On histopathology of the lungs there was evidence of mild suppurative bronchopneumonia suggesting that a suppurative placentitis was present. There was also evidence of a mild necro-suppurative hepatitis. Bacterial cultures from foetal tissues failed to yield any recognised pathogens. Placentas were not available for examination.

Ringworm due to Trichophyton mentagrophytes was diagnosed in in-pig gilts on a gilt service unit. The gilts had been kept in outdoor pens for 2 – 3 weeks on arrival but were indoors at the time the lesions were seen.  Two groups of gilts were affected and the morbidity rate was approximately 20%. The head, neck and in some cases the flanks were affected with multiple, raised, erythematous circular lesions, which had central exudation.

Alimentary tract disorders

Swine dysentery was diagnosed in two herds that had clinical outbreaks of diarrhoea in growing and finishing pigs. Brachyspira hyodysenteriae was confirmed by PCR test and culture.

A fifteen-week-old boar with a history of ill-thrift was found to have a large multi- lobulated, pedunculated mass measuring approximately 20 x 8 cm in the lumen of the colon. Grossly it resembled a large intestinal tumour (Fig 5 - see top right-hand side). On histopathology the lesion comprised large polypous areas of mucosal adenomatous change. The crypts were well formed but the mucosa was very hyperplastic and some crypts contained inflammatory cells and/or abscesses. Silver staining showed large numbers of curved, rod shaped bacteria within the apical cytoplasm of epithelial cells lining affected crypts, consistent with Lawsonia intracellularis infection (Fig 6 - see top right-hand side). This type of large solitary lesion is a very unusual manifestation of Lawsonia intracellularis infection.

Gastric ulceration and acute haemorrhage were the cause of death of a  20-week-old gilt which was found dead. It was one of eight pigs to have died that week. The stomach was distended with free blood and large blood clots. Concurrent enzootic-type pneumonia was present in the lungs. Pasteurella multocida and Streptococcus suis serotype 2 were isolated in culture from pneumonic lesions.