PubMed HealthSearch

Biomedical subjects

S H Done

Publications and source records attributed to S H Done.

At least 19 recordsLinked to original sources

Infection of pigs and cattle with bovine viral diarrhoea virus on a farm in England.

Deaths within a litter of sucking pigs led to a suspicion of hog cholera, but pestiviruses isolated from both dead and live piglets appeared to be bovine viral diarrhoea virus. Persistent viraemia with bovine viral diarrhoea virus was demonstrated in living littermates and also in a bought-in calf, housed in a nearby pen on the same farm. Only two of the littermates survived, both of which had been virus negative and seropositive from the outset of testing. Porcine and bovine virus isolates grew well in calf testicular cells and were neutralised equally by sera collected at the farm from cattle and pigs. However, a comparison by means of their reactivity to monoclonal antibodies showed that they were similar but not identical, and only the porcine isolates grew well in a porcine kidney cell line.

Animals

Natural scrapie in goats: neuropathology.

The brains of the 20 goats affected with natural scrapie received at the Central Veterinary-Laboratory, Weybridge, since 1975 were examined microscopically. Lesions of a spongiform encephalopathy were found in the brainstem, cerebellum, diencephalon, corpus striatum, and also in the neopallium or cerebral cortex. The lesions in the neopallium have not previously been reported in natural scrapie in goats. Deposits of amyloid were present in the thalamus in three of the 20 goats.

Animals

Natural scrapie in goats: case histories and clinical signs.

The case histories of the 20 goats affected with natural scrapie which have been examined since 1975 at the Central Veterinary Laboratory, Weybridge, are reviewed. Their ages ranged from two to seven years (median three years, four months) and 85 per cent of them were between two and four years old. The most common clinical signs were hyperaesthesia, ataxia and pruritus. The histories indicated that scrapie can occur in goats which have not been in contact with sheep.

Animals

The natural occurrence of scrapie in moufflon.

Six cases of scrapie were confirmed in two separately maintained flocks of moufflon, in both of which the disease appeared to be endemic. The clinical signs and histopathology were indistinguishable from those observed in scrapie-affected domesticated sheep. The pathology included lesions in the cerebral cortex which, although commonly present in scrapie-affected sheep, have not previously been described in the natural disease.

Animals

Isolation of a Lelystad virus-like agent from British pigs and scanning electron microscopy of infected macrophages.

Six, one-week-old gnotobiotic piglets were inoculated with tissues or sera collected from field cases of porcine reproductive and respiratory syndrome. The piglets showed little or no illness, and two that were necropsied at 8 and 9 days post infection appeared grossly normal. However, a Lelystad virus-like agent was isolated from most of the inoculated pigs using porcine alveolar macrophage cultures. Seroconversion to the Lelystad virus was observed and some animals developed microscopically detectable interstitial pneumonias. Scanning electron microscopy was used to study the in vitro cytopathic effect of the Lelystad virus on porcine alveolar macrophages.

Abortion, Veterinary

Reduction in the length of the intravesical ureter associated with pyelonephritis in the adult pig.

The ureterovesical junction of pigs with cystitis and pyelonephritis was examined. There was significant shortening of the intravesical portion of the ureter in sows with pyelonephritis. In cases associated with acute pyelonephritis the ureteric orifice was found to be significantly wider than that found in the normal population. The ratio of the intravesical length to the ureteric orifice diameter was also significantly reduced. It is postulated that these changes to the ureterovesical junction originate or are caused by the disease processes in the bladder and may allow vesicoureteric reflux to occur, leading to ascending pyelonephritis.

Animals

Citrinin as a possible cause of the pruritus, pyrexia, haemorrhagic syndrome in cattle.

An outbreak of the pruritus, pyrexia, haemorrhagic syndrome affected eight of a herd of 175 cows which was divided into two groups of 115 and 60 according to yield. There was no difference in management between them but citrus pulp pellets were fed only to the larger group in which the eight cows were affected. Silage, which had been made without the use of additives, was also fed to both groups. The citrus pulp was visibly mouldy and contained 30 to 40 parts per billion of citrinin. Signs of the syndrome occurred within three days of the cows starting to ingest the citrus pulp, which was fed for 21 days, and the last case occurred six days after the feeding of citrus pulp ceased. Five calves whose dams had been fed citrus pulp were subsequently born with superior prognathism. In contrast to the eight cows that developed the syndrome only one out of 68 heifers which were fed larger quantities of citrus pulp for 10 days developed mild signs of the syndrome and then recovered, suggesting that older animals may be more susceptible. The clinical signs, gross pathology and histopathology are described and compared with those of previous outbreaks. Mycotoxins, particularly citrinin, were strongly implicated as the cause of this outbreak.

Animal Feed

Environmental factors affecting the severity of pneumonia in pigs.

The variable manifestations of respiratory problems in finishing pigs have led to the concept of a multiple-factor aetiology for swine respiratory disease and in particular for enzootic pneumonia. The primary and secondary agents of the disease produce their most detrimental economic effects and the highest levels of mortality and morbidity during the finishing period, when the economics of production necessitate indoor housing and intensification. This paper considers the contribution of four main groups of environmental factors to the high levels of clinical disease and lesions which are found whenever large numbers of pigs are examined at slaughter. They are meteorological factors, population and social factors, management factors and airborne pollution.

Age Factors

Natural scrapie: detection of fibrils in extracts from the central nervous system of sheep.

Extracts from the cervical spinal cord and from the medulla, thalamus, cerebellum and cerebral cortex of the brains of 10 sheep, histopathologically confirmed as cases of scrapie, were examined by electron microscopy for the presence of scrapie-associated fibrils. Characteristic fibrils were observed in all the extracts except for that from the thalamus of one sheep. No fibrils were found in any extracts from three control sheep. A comparison of these results with a similar study of 22 cases of bovine spongiform encephalopathy (BSE) suggests that in cases of scrapie the area of the brain chosen for the detection of fibrils is less critical than in cases of BSE, in which fibrils are more readily extracted from areas of the brain stem.

Animals

Concurrent maedi-visna virus infection and pulmonary adenomatosis in a commercial breeding flock in East Anglia.

The seroprevalence of maedi-visna virus infection in thin potential cull ewes aged over two years in a flock in East Anglia increased from 3.7 per cent in August 1985 to 39.0 per cent in September 1987 and 93.3 per cent in May 1989. This increase coincided with the first appearance of sheep pulmonary adenomatosis in the flock. Four emaciated ewes which were dyspnoeic were necropsied between 1987 and 1989. Maedi and pulmonary adenomatosis were confirmed histologically in one of these ewes and pulmonary adenomatosis was confirmed in the other three.

Animals

Detachment of the ischial tuberosity sows.

The clinical and pathological features of five cases of detachment of the ischial tuberosity are described. In two cases, the detachment occurred unilaterally; one was a gilt showing severe lameness which precluded mating and the other was a uniparous sow which showed only slight lameness. Three gilts which were affected bilaterally developed progressive lameness during pregnancy and were unable to stand after farrowing. One of these gilts died and two had to be slaughtered. The diagnostic features of the epiphyseal detachment were shortening of the caudal extremity of the ischium, palpation of the displaced ischial tuberosity and crepitation elicited by pressing the displace tuberosity against the ischium.

Animals