Veterinary Services

Acute diarrhoea associated with Type C rotavirus infection was diagnosed in two to three-day-old piglets, in a herd with ongoing neonatal scour problems. The histopathological changes in the small intestines were typical of an acute viral-type enteropathy such as rotavirus. They included loss of epithelium from villus tips, early inflammatory cell infiltrates in the lamina propria of the villus tips, villus atrophy and bridging of villi.

A series of pigs ranging from four to six weeks old were submitted from the same unit over a three week period to investigate a steady increase in the mortality rate among weaners. Two pigs had been weaned three days previously and had died suddenly. The findings were similar in both pigs and comprised an excess of clear, straw coloured pleural, pericardial and peritoneal fluid with fibrin strands present. The lungs were congested. Bacterial cultures were unrewarding. On histopathological examination both piglets had lesions of mulberry heart disease. Two five- to six-week-old pigs had similar findings but a third had subacute-to-chronic cardiac changes suggestive of subclinical mulberry heart disease. The chronic changes were comprised of a random pattern of loss of myocardial fibres with fibrous replacement and mononuclear cell infiltration indicating a chronic myocarditis. However there were also areas of acute myocardial degeneration and haemorrhage between fibres consistent with acute stage lesions. The findings suggested that this pig has had subclinical mulberry heart disease that had culminated in an acute clinical episode when stressed. Although inadequate available vitamin E in myocardial tissue is believed to be the cause, the liver vitamin E level in the latter pig was 4.281 umol/kg FT (reference range >3.5 umol/kg FT).

Chronic wasting illness and sudden deaths in healthy-looking pigs were reported in a group of 11 to 12-week-old growers. The pigs were vaccinated against Mycoplasma hyopneumoniae. All were found to have extensive pulmonary consolidation associated with complex pneumonia changes comprised of bacterial and viral-type pneumonias. Interestingly, in one of the pigs, the small intestinal sections showed acute enteritis with widespread coliform attachment to the surface epithelium. Occasional small foci of similar attachment were present in the colon. Acute enteritis with attaching coliforms is unusual in a pig of this age. A profuse growth of coliforms had been isolated in culture from the intestinal contents but the plate had been overgrown by Proteus. The lymphoid tissues did not show any evidence of postweaning multisystemic wasting syndrome in these cases.

A three-month-old Wild Boar that had been noted as poorly thriven and losing weight prior to death was submitted from an outdoor rearing unit. At necropsy the respiratory tract revealed a very large number of worms clumped together along the length of the trachea and throughout the bronchi and bronchioles. The density of worms blocked most of the main lung airways (figure 6 - see top right-hand). The liver was congested, but no other significant gross lesions were recorded on further examination of the carcase. The worms were identified as Metastrongylus elongata (apri). These species-specific lungworms use earthworms as an intermediate host and can survive in the soil for several years. Death was probably a result of an obstruction caused by the sheer volume of worms present within the airways.

Sarcoptic mange was confirmed from ear wax samples from representative numbers of pig’s ears removed after slaughter as part of a mange screening programme. Of 25 herds, 15 were found to be positive, while no mites were detected in any of the ears from 10 herds. Sarcoptic mange was also confirmed from skin scrapings submitted from gilts in a herd with a clinical mange problem.