noun[mass noun] Veterinary Medicine
- A fatal disease of sheep in which there is progressive demyelination of neurons in the brain and spinal cord, caused by the maedi virus.More example sentences
- It is a voluntary scheme with over 2800 flocks that have been blood tested and are accredited free of Maedi visna.
- We conclude that sheep sera have a visna virus inhibiting factor and hypothesise that VIF inhibits early spread of visna virus in inoculated sheep and may be involved in initiating the persistent infection.
1950s: from Old Norse, 'to wither'.
More definitions of visnaDefinition of visna in:
- The US English dictionary