| 释义 |
visna Vet. Sci.|ˈvɪznə|
Also Visna.
[a. ON. visna to wither.]
A fatal disease of sheep in which there is progressive demyelination of neurones in the brain and spinal cord. Freq. attrib.
1957Jrnl. Neuropath. & Exper. Neurol. XVI. 389 (heading) Visna, a demyelinating transmissible disease of sheep. Ibid. 393 This experiment obviously does not prove conclusively that Visna-sera will specifically neutralize Visna-virus but it is consistent with such an explanation. 1970Jubb & Kennedy Path. Domestic Animals (ed. 2) I. 269/2 The virus of visna can be transmitted by intra-pulmonary injection. 1982Jrnl. Neuro⁓immunology III. 140 Icelandic sheep are free of natural infection since visna virus has been eradicated from the whole country.
Add:b. Comb.: visna-maedi, infection of sheep or goats by the visna-maedi virus, a lentivirus which may give rise to visna or maedi; cf. maedi-visna s.v. *maedi n. b.
1972Deutsche Tierarztliche Wochenschr. LXXIX. 12/2 (heading) Visna/maedi in German mouton merinos in Unterfranken/Germany. 1974Progress Med. Virol. XVIII. 338 Infectivity of faeces and urine in visna-maedi has not been tested extensively enough to allow any general statements. 1980Jrnl. Gen. Virol. L. 69 The agent is a retrovirus, having a virion-associated reverse transcriptase enzyme and an antigenic determinant(s) which cross-reacts with the p30 of visna-maedi viruses. 1982R. A. Weiss in B. W. J. Mahy et al. Virus Persistence 267 The Lentivirinae or slow viruses of which visna-maedi virus is the only well studied example. |