The Infectious Dose of Variola (Smallpox) Virus

Details

• Personal Author:
  Hubbard AE ; Jones RM ; Nicas M ; Reingold AL
• Description:
  Quantitative estimation of an individual's risk of infection due to airborne pathogens requires knowledge of the pathogen's infectious dose, in addition to estimates of the pathogen's airborne concentration and the person's exposure duration. Based on our review of the published literature on poxvirus infection, we conclude that the infectious dose of variola (smallpox) virus is likely one virus particle and that infection can be initiated in either the upper respiratory tract or pulmonary region. Studies of airborne transmission of poxvirus in monkeys and rabbits show that primary infection can occur in both regions of the respiratory tract. A quantitative study of poxvirus inhalation transmission in rabbits indicates that the deposition of one pock-forming unit (PFU) carried on respirable particles can cause infection. Findings in both in vitro and in vivo studies of the number of virus particles comprising a PFU are consistent with a "one-hit" phenomenon--namely, the cellular uptake of just one virus particle can lead to infection of a cell or an area of cell growth, creating a pock (an infected area of cells). Variability in virulence among different virus strains may involve differences in the probability of infection per virus particle, where a highly virulent strain has a probability close to one of successful infection for each virus particle. In an analogous manner, variability in susceptibility to the same virus strain among different hosts may involve differences in the probability of infection per virus particle across different hosts. [Description provided by NIOSH]
• Subjects:
  Aerosols Air Pollutants, Occupational Air Pollution, Indoor Bacteria Bacterial Infections Dust Environmental Exposure Environmental Monitoring Environmental Pollution Hazardous Substances Immune System Occupational Health Particulate Matter Personal Protective Equipment Public Health Respiratory System Risk Assessment Risk Factors Safety

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• Keywords:
  Aerosol-particles Air-contamination Airborne-particles Bacterial-disease Bacterial-dusts Bacterial-infections Biological-effects Cell-biology Cellular-reactions Environmental-exposure Environmental-hazards Exposure-assessment Exposure-levels Exposure-methods Health-hazards Immune-reaction Immune-system In-vitro-studies Inhalation-studies Pathogenesis Pathogens Physiological-effects Physiological-factors Physiological-function Physiological-response Protective-measures Public-health Quantitative-analysis Risk-analysis Risk-factors Statistical-analysis Surface-properties

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• ISSN:
  1535-6760
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  California ; OSHA Region 9
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  118-127
• Volume:
  9
• Issue:
  3
• NIOSHTIC Number:
  nn:20037359
• Citation:
  Appl Biosafety 2004 Sep; 9(3):118-127
• Contact Point Address:
  Mark Nicas, University of California-Berkeley, Berkeley, California
• Federal Fiscal Year:
  2004
• Performing Organization:
  University of California, Berkeley
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Applied Biosafety
• End Date:
  20250630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:ebc8339b2b8ab4e9246e963c671a0d0dd1cb0c4ea35d6b614238931bc0e8aabd3856ae137129689e9b089f44e83bd539956a15caab0ca0126346d7304b37681f
• Download URL:
  https://stacks.cdc.gov/view/cdc/188460/cdc_188460_DS1.pdf
• File Type:
  [PDF - 328.49 KB ]