Veterinary Services

Generalised and systemic conditions

Three sows were submitted from an outdoor herd in Morayshire, where seven dry sows had been found dead that morning, after being moved to a different paddock the day before. Six of the sows were found in one paddock but were not lying close together. Microscopic testing for anthrax was carried out on the three sows and in smears from one of these, chains of square-ended bacilli with broken, purple capsules were observed. Other bacilli present had clear capsules.

There were also smaller numbers of rod-shaped bacteria with morphology suggestive of Clostridium novyi. Following a consultation visit from the local Amimal Health Office, it was decided that the smears were suspicious of anthrax and a form A was served on the laboratory and on the farm. Tests were carried out on an organism isolated from material submitted to VLA Weybridge before Bacillus anthracis could be excluded. Due to the restrictions imposed, post mortem examinations were not performed and the cause of the deaths remains obscure. Although the sows were not all found dead in the same area, electrocution could not be ruled out. No further similar deaths have been reported.

Streptococcal meningitis and septicaemia due to Streptococcus suis serotype 2 was diagnosed in a twelve-week-old pig from a "high health" unit. Three "sudden deaths" had been reported out of a group of 160 and a number of other pigs showing meningitis-like signs had been treated with penicillin, some making a successful recovery. The source of this apparent outbreak is not known.

An outbreak of apparent meningitis in piglets and recently weaned pigs on one unit prompted submission of three affected animals for post mortem examination. All three presented in lateral recumbency and were unable to stand. Pigs were pyrexic, dull and depressed but did not exhibit any specific neurological deficits. The gross findings in two one-week-old pigs consisted of fibrinopurulent polyarthritis (including the atlanto-occipital joint) and mild meningitis. S. suis serotype 1/14 was isolated from joints and brain. The gross lesions in the four-week-old pig were suggestive of an extensive bacterial bronchopneumonia and septicaemia, confirmed on histopathological examination of tissues. A light growth of Pasteurella multocida was isolated from the brain but no organisms were isolated from the lung or kidney; perhaps a reflection of previous antibiotic therapy. The unit had a long history of disease due to S. suis serotype 2 in weaned pigs and serotype 1/14 had not been previously isolated. Recent introduction of breeding stock from a different source to that previously used was highlighted as a possible factor in the outbreak.

Alimentary tract disorders

Proliferative enteropathy was diagnosed as the cause of diarrhoea and poor condition in an eleven-week-old pig from an organic unit reporting occasional scour in this age group. The ileal mucosa showed characteristic proliferative changes and, in addition, there was evidence of bacterial-type colitis without any histopathological evidence of mucosal proliferation. Warthin-Starry staining of histological sections of affected colon demonstrated heavy infection of the mucosa with organisms resembling Lawsonia intracellularis, although polymerase chain reaction (PCR) testing for specific DNA was not attempted.

Musculo skeletal conditions

Actinobacillus suis was isolated from the metacarpo-phalangeal joint of an eleven-day-old piglet from a large farrow-to-finish unit where increased cases of single joint arthritis were reported across numerous litters. The unit had a history of pre- and peri-weaning streptococcal arthritis problems and it is not known whether this particular case was representative of the recent upsurge in arthritis cases. Sporadic cases of A. suis arthritis had been diagnosed seven years previously, shortly after restocking, but piglet deaths from septicaemia due to this organism have never been reported on the unit.