Inactivation of the Scrapie Agent by Near Monochromatic Ultraviolet Light

Article metrics


SCRAPIE is a progressive degenerative disease of the central nervous system of sheep. Because the disease is transmitted by cell-free filtrates the agent has been classified as a virus, but its response to many chemical and physical treatments has long been known to differ from that of “conventional” viruses. The transmitting agent increases greatly in quantity in the animal host. In the terminal stages of the disease in mice, preparations from the brain must usually be diluted by a factor of 107–108 to give an average of one mean lethal dose per unit volume, whatever the original inoculum to the affected mouse has been. Haig and Clarke1, who used a substantial starting inoculum to follow the “growth” of the agent, showed an increase by a factor of 104 in the titre of the agent in mouse brain by the time the terminal stage was reached. But experiments with ionizing and ultraviolet radiations led Alper et al.2,3 to question whether the agent depended on replication of a nucleic acid moiety for proliferation, which was shown to occur also when the titre of the injected material had been reduced by irradiation in vitro4. The dose of ionizing radiation required to give an average of one inactivating event per infective unit was much larger, and the inferred “target volume” (molecular weight about 1.5 × 105, ref. 2) therefore much smaller, than for any virus; if the “target” were nucleic acid, this molecular weight would be too low to allow of sufficient coding information for replication. With ultraviolet irradiation at 254 nm, detectable inactivation required doses which were very large compared with those which inactivated even the most “resistant” entities whose function depended on the integrity of nucleic acid3,4. This suggested that the agent might be comparatively transparent to ultraviolet of wavelength in the “germicidal” region in which nucleic acids absorb most strongly.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Haig, D. A., and Clarke, M. C., Slow, Latent and Temperate Virus Infections, US Public Health Service Publications No. 1378, 215 (1965).

  2. 2

    Alper, T., Haig, D. A., and Clarke, M. C., Biochem. Biophys. Res. Commun., 22, 278 (1966).

  3. 3

    Alper, T., Cramp, W. A., Haig, D. A., and Clarke, M. C., Nature, 214, 764 (1967).

  4. 4

    Haig, D. A., Clarke, M. C., Blum, E., and Alper, T., J. Gen. Virol., 5, 455 (1969).

  5. 5

    Magnus, I. A., Porter, A. D., McCree, K. J., Moreland, J. D., and Wright, W. D., Brit. J. Dermatol., 71, 261 (1959).

  6. 6

    Muel, B., and Malpièce, C., Photochem. Photobiol., 10, 283 (1969).

  7. 7

    Hatchard, C. G., and Parker, G., Proc. Roy. Soc., A, 253, 518 (1956).

  8. 8

    Alper, T., Hornsey, S., Pike, M. C., and Smith, P., in Effects of Radiation on Cellular Proliferation and Differentiation, 515 (Intern. Atomic Energy Agency, 1968).

  9. 9

    Rushizky, G. W., Knight, C. A., and McLaren, A. D., Virology, 12, 32 (1960).

  10. 10

    Zelle, M., and Hollaender, A., J. Bact., 68, 210 (1954).

  11. 11

    Powell, W. F., and Setlow, R. B., Virology, 2, 337 (1956).

  12. 12

    Setlow, R., Biochim. Biophys. Acta, 39, 180 (1960).

  13. 13

    Setlow, J. K., and Setlow, R. B., Proc. US Nat. Acad. Sci., 47, 1619 (1961).

  14. 14

    Winkler, U., Johns, H. E., and Kellenberger, H. E., Virology, 18, 343 (1962).

  15. 15

    Kassanis, B., and Kleczkowski, A., Photochem. Photobiol., 4, 209 (1965).

  16. 16

    Kleczkowski, A., and Govier, D. A., Photochem. Photobiol., 10, 53 (1969).

  17. 17

    Marsh, D. G., and Crutchley, M. J., J. Gen. Microbiol., 47, 405 (1967).

  18. 18

    Ekert, B., Muel, B., and Latarjet, R., Biochim. Biophys. Acta, 204, 275 (1970).

  19. 19

    Hollaender, A., and Duggar, B. M., Proc. US Nat. Acad. Sci., 22, 19 (1936).

  20. 20

    McLaren, A. D., Photochem. Photobiol., 8, 521 (1968).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

LATARJET, R., MUEL, B., HAIG, D. et al. Inactivation of the Scrapie Agent by Near Monochromatic Ultraviolet Light. Nature 227, 1341–1343 (1970) doi:10.1038/2271341a0

Download citation

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.