Characteristic behaviour and symptoms in cattle affected by BSE are nervousness or aggression, uncoordination including difficulty walking and rising, decreased production of milk and weight loss. Most cases occur in cows between 3 to 6 years of age with virtually no cases in calves. The incubation period varies from 2 to 8 years, after the onset of clinical symptoms death result in 2 weeks to 6 months. Scrapie Scrapie is a TSE that occurs commonly amongst in goats and sheep. Scrapie in characterised by behavioural changes, tremor, weight loss and uncoordinated movements.
Affected animals itch and rub against objects hence the name scrapie.
The disease is classified as a slow infection with asymptomatic incubation periods of months, years and perhaps decades. Death typically occurs one to sixth months after clinical symptoms appear. Transmission is thought to occur both horizontally and vertically, the most common method being ewe to offspring and other lambs through contact with the placenta and placental fluids. Scrapie has been transmitted to other mammals in the laboratory, always inducing a scrapie like disease, although at present there is no scientific or epidemiological evidence that it can be transmitted to humans. Human TSEs CJD CJD is a rare and fatal neurodegenerative condition that occurs in humans.