Hostname: page-component-78c5997874-g7gxr Total loading time: 0 Render date: 2024-11-19T11:47:20.548Z Has data issue: false hasContentIssue false
  • English
  • Français

Overlap and the errors of plaque counting: I. The overlap biases of observed counts and their correction

Published online by Cambridge University Press:  15 May 2009

D. W. Howes
D. W. Howes
Affiliation:
Viral Products Section, National Biological Standards Laboratory, Commonwealth Department of Health, Melbourne, Victoria, Australia
Rights & Permissions [Opens in a new window]

Summary

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The number of plaque-forming units is underestimated if plaques overlap. A simple model was developed to account for this bias, and tested by an extensive experimental analysis. It is shown that models of this type are inadequate, but can be modified to give objective methods for setting limits to the acceptable counting range, and for correcting the overlap bias of observed counts which fall within this range.

Where overlapping of plaques is a significant source of error, these methods will improve the efficiency of plaque assays and will render the statistical analysis of counting data more reliable.

Type
Research Article
Information
Journal of Hygiene , Volume 67 , Issue 2 , June 1969 , pp. 317 - 334
Copyright
Copyright © Cambridge University Press 1969

References

REFERENCES

Armitage, P. (1949). An overlap problem arising in particle counting. Biometrika 36, 257–66.CrossRefGoogle ScholarPubMed
Berg, G., Harris, E. K., Chang, S. L. & Busch, K. A. (1963). Quantitation of viruses by the plaque technique. J. Bact. 85, 691–700.CrossRefGoogle Scholar
Bourdillon, R. B., Lidwell, O. M. & Lovelock, J. E. (1948). Studies in Air Hygiene. Spec. Rep. Ser. med. Res. Coun. no. 262.Google Scholar
Cooper, P. D. (1961). The plaque assay of animal viruses. Adv. Virus Res. 8, 319–78.CrossRefGoogle ScholarPubMed
Cooper, P. D. (1967). The plaque assay of animal viruses. In Methods in Virology (ed. Maramorosch, and Koprowski, ), vol. III, p. 243. Academic Press.Google Scholar
Dulbecco, R. & Vogt, M. (1954). Plaque formation and isolation of pure lines with poliomyelitis viruses. J. exp. Med. 99, 167–82.CrossRefGoogle ScholarPubMed
Higgins, P. D. (1965). A comparative study of a plaque and quantal method for assaying the neutralizing activity of antisera to type 1 poliovirus. J. Hyg., Camb. 63, 311–25.CrossRefGoogle ScholarPubMed
Howes, D. W. & Fazekas De St Groth, S. (1969). Overlap and the errors of plaque counting. II. The bias of the variance and the concealment of errors. J. Hyg., Camb. 67, 335.CrossRefGoogle ScholarPubMed
Irwin, J. G., Armitage, P. & Davies, C. N. (1949). Overlapping of dust particles on a sampling plate. Nature, Lond. 163, 809.CrossRefGoogle ScholarPubMed
Larsen, S. O. & Reinicke, V. (1965). Some statistical problems in relation to the use of the Poisson distribution in virus plaque assays. Acta. path. microbiol. scand. 65, 84–92.CrossRefGoogle Scholar
Lorenz, R. J. & Zoeth, B. (1966). An estimation of the overlap bias in plaque assay. Virology 28, 379–85.CrossRefGoogle ScholarPubMed
Roach, S. A. (1968). The Theory of Random Clumping. London: Methuen.Google Scholar
Thayer, J. (1965). The suitability of silvered leaf monkey (Presbytis cristatus) kidney cell cultures for testing poliovirus vaccines. Aust. J. exp. Biol. med. Sci. 43, 803–8.CrossRefGoogle ScholarPubMed