Experimental microcyst sarcocystis infection in lambs: pathology.

Six 34- to 42-day-old lambs raised in coccidia-free conditions were inoculated with 70,000 sporocysts derived from sheep heart with microscopic sarcocysts. Fever and mild anorexia occurred between 25 and 33 days after inoculation. A transient anaemia was most marked 32 days after inoculation. Lambs were killed and examined 14, 25, 33, 42, 60 and 81 days after inoculation. Gross lesions were absent. First and second generation meronts were present in endothelial cells at 25 and 33 days after inoculation. Meronts were most numerous in kidney glomeruli. Developing sarcocysts were rare at 42 days after inoculation. Sarcocysts with a primary cyst wall 2 to 3 micron thick composed of palisade projections were common at 60 and 81 days after inoculation in striated muscle and brain. Mild to severe striated muscle myositis and non-suppurative encephalitis or encephalomyelitis with glial nodules were observed 25 to 81 days after inoculation. Sarcocyst frequency varied considerably; it was highest in myocardium, M vastus intermedius, M vastus medialis, M extensor carpi radialis and tongue muscle and was lowest in M masseter.

Border disease of sheep: spinal cord morphometry.

Semi-automated planimetry was used to determine cross-sectional areas of spinal grey and white matter by direct microscopy of paraffin sections of spinal cord from Border disease (BD) and normal lambs at segments C4, C8, T6 and L4. Spinal cord cross-sectional area was significantly reduced in cases of BD produced by either intramuscular or intranasal inoculation of ewes in the first half of pregnancy with Weybridge strains of BD virus. The reduction was apparent at all 4 levels and in both grey and white matter, though the white matter was the more severely affected. Spinal cord areas tended to be smaller in the progeny of ewes exposed earlier in gestation or to larger doses of virus, but these differences were not statistically significant.

Atrophic rhinitis: snout morphometry for quantitative assessment of conchal atrophy.

Morphometric methods, either point counting or semiautomated planimetry, can be applied to photographic or impression prints of sections of the pig snout to measure the extent of conchal atrophy on a continuous scale as a morphometric index. Though relatively time consuming, the technique yields highly repeatable parametric data which do not depend heavily on expert, subjective judgment. It is therefore particularly suitable for quantitative analysis of the effects of experimental treatments or changes in management.