Animals were experimentally infested with Sarcoptes scabiei var suis at weekly intervals between birth and five weeks of age. Excoriations were observed on the luminal surface of the ear seven days after the initial infestation. Encrusted lesions developed in the ears of all pigs between the third and eighth weeks but spontaneously regressed and disappeared by the 14th week. A generalised pruritus, accompanied by focal erythematous skin lesions developed in a majority of pigs between seven and 11 weeks of age. The presence of pruritus was associated with an eosinophilia and histological changes in the skin which were consistent with an allergic reaction. The results are discussed in relation to their diagnostic significance and their importance in the control and eradication of the disease.

A study on the development and effect of experimental Sarcoptes scabiei var suis infestations in growing pigs is described. Pigs were infested at either weekly or fortnightly intervals throughout each experimental and individual growth rates and feed conversion ratios were determined. The animals were fed diets which contained either optimal or sub-optimal levels of protein. They were housed either intensively or extensively. In all experiments the majority of infested animals developed a generalised hypersensitivity to sarcoptes mites and performed significantly less efficiently than non-infested littermates. Mean growth rates were depressed from 9.2 to 12.5 per cent and feed conversion efficiencies by a similar margin. Well fed, intensively housed pigs developed a more severe hypersensitivity reaction than poorly fed, extensively housed pigs.

Caseous lymphadenitis was the most frequently encountered pathological condition in 3,720 feral goats examined during routine meat inspection procedures. Among 9 separate consignments of animals, the prevalence of infection averaged 7.4% (range 0.3% to 18.8%). The majority of lesions were seen in lymph nodes draining superficial body areas although many also occurred in internal nodes and organs. Corynebacterium ovis was isolated from 25 of 32 lesions submitted for bacteriological examination. Other conditions regularly encountered included pneumonia, cysticercosis, sarcosporidiosis and lice infestation, while myonecrosis, pleurisy, pericarditis, nephritis, hepatitis, cirrhosis and mite infestation were only occasionally found. A total of 171 serum samples were collected and tested against 17 antigens. Samples from 57.9% and 51.5% of goats showed positive serological reactions to the antigens for sarcosporidiosis and Q fever respectively.

The protection conferred on pregnant gilts by 2 commercially available leptospira interrogans serovars pomona and tarassovi bacterins was evaluated. Gilts vaccinated either 3, 6 or 12 months prior to natural challenge with L. interrogans serovar pomona had significantly lower abortion rates (2% vs 69%) and foetal mortality rates (14% vs 57%) than unvaccinated controls. One vaccine was significantly superior to the other and contained approximately twice the number of L. interrogans serovar pomona organisms per vaccine dose. Neither vaccine protected against renal colonisation but vaccination reduced urinary excretion of leptospires. Both vaccines reduced agglutinating antibody response to infection, as measured by the microscopic agglutination (MA) test. This may prevent the detection of a carrier animal by serology. Foetal pigs did not develop specific MA titres. Cultural methods were not reliable in making a diagnosis of foetal infection. Histopathology of foetal liver and kidneys helped in making a diagnosis of foetal infection.

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