Minimal infective dose
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Infectious dose (ID) is the amount of pathogen (measured in number of microorganisms) required to cause an infection in the host.[1]
Usually it varies according to the pathogenic agent and the consumer's age and overall health.
Infectious doses for some known microorganisms
- Escherichia coli : very large (106 - 108 organisms)
- Salmonella : quite large in order to definitely establish infection (e.g. >105 organisms) but infection may also be established by lower numbers (e.g. 10s of organisms) [2]
- Vibrio cholerae : relatively large (104 - 106 organisms)
- Bacillus anthracis : relatively large (104 spores)
- Campylobacter jejuni: low (500 organisms)
- Francisella tularensis: very low (10-50 organisms)
- Shigella : very low (10s of organisms)
- Cryptosporidium parvum : very low (10 to 30 oocysts)
- Escherichia coli O157:H7 : very low (<10 organisms)
- Mycobacterium tuberculosis : very low (<10 organisms) [3]
- Entamoeba coli : extremely low (from 1 cyst)
The likelihood of infection in all cases is also linked to the immune status of the individual (immunocompromised individuals may become infected more readily).[4]
References
- ^ Leggett, H. C., et al. (2012). "Mechanisms of Pathogenesis, Infective Dose and Virulence in Human Parasites." PLoS Pathog 8(2): e1002512.
- ^ Hara-Kudo, Y., & Takatori, K. (2011). Contamination level and ingestion dose of foodborne pathogens associated with infections. Epidemiology and infection, 139(10), 1505-1510.
- ^ 1.Pfyffer, G. E. (2007). Mycobacterium: General Characteristics, Laboratory Detection, and Staining Procedures. In P. R. Murray (Ed.), Manual of Clinical Microbiology (9th ed., pp. 543-572). Washington D.C.: ASM Press.
- ^ Hara-Kudo, Y., & Takatori, K. (2011). Contamination level and ingestion dose of foodborne pathogens associated with infections. Epidemiology and infection, 139(10), 1505-1510.