Porcine congenital tremor type AII: Spinal cord morphometry

Abstract Semi-automated planimetry was used to determine cross-sectional areas of spinal grey and white matter of baby piglets by direct microscopy of Woelcke-stained sections at levels C 3 , T 1–2 , T 7–8 and L 5–6 . The specimens came from 16 cases of porcine congenital tremor type AII (CT AII) experimentally induced by infecting sows, when 30 days pregnant, with the Weybridge CT AII agent (presumed to be a virus) and from nine normal controls of the same age. Affected piglets showed mean reductions in spinal cord cross-sectional areas of about 5% for grey matter, 15% for white matter and 12% for grey and white matter combined. The reduction was apparent at all four levels of the spinal cord studied. However this pattern did not differ in a diagnostically useful way from that seen in congenital tremor type AI (CT AI), after allowing for the potentially confounding effects of within-litter variation and varying gestation age at time of exposure.