Fomite

A fomite (/ˈfoʊmaɪt/) or fomes (/ˈfoʊmiːz/) is any inanimate object that, when contaminated with or exposed to infectious agents (such as pathogenic bacteria, viruses or fungi), can transfer disease to a new host.[1] In the 21st century, the role of fomites in disease transfer is higher than ever in human history because of indoor lifestyle.[2]

Transfer of pathogens by fomites

A fomite is any inanimate object (also called passive vector) that, when contaminated with or exposed to infectious agents (such as pathogenic bacteria, viruses or fungi), can transfer disease to a new host.[1] Contamination can occur when one of these objects comes into contact with bodily secretions, like nasal fluid, vomit, or feces. Many common objects can sustain a pathogen until a person comes in contact with the pathogen, increasing the chance of infection. The likely objects are different in a hospital environment than at home or in a workplace.

Hospital fomites

Detecting whether medics have inadvertently transferred fluids to their clothing during a training sequence using simulated bodily fluids carrying an ultraviolet dye

For humans, common hospital fomites are skin cells, hair, clothing, and bedding.[3]

Fomites are associated particularly with hospital-acquired infections (HAIs), as they are possible routes to pass pathogens between patients. Stethoscopes and neckties are common fomites associated with health care providers.[4] It worries epidemiologists and hospital practitioners because of the growing selection of microbes resistant to disinfectants or antibiotics (so-called antimicrobial resistance phenomenon).

Basic hospital equipment, such as IV drip tubes, catheters, and life support equipment, can also be carriers, when the pathogens form biofilms on the surfaces. Careful sterilization of such objects prevents cross-infection.[5] Used syringes, if improperly handled, are particularly dangerous fomites.

Daily life

In addition to objects in hospital settings, other common fomites for humans are cups, spoons, pencils, bath faucet handles, toilet flush levers, door knobs, light switches, handrails, elevator buttons, television remote controls, pens, touch screens, common-use phones, keyboards and computer mice, coffeepot handles, countertops, drinking fountains, and any other items that may be frequently touched by different people and infrequently cleaned.

Cold sores, hand–foot–mouth disease, and diarrhea are some examples of illnesses easily spread by contaminated fomites.[6] The risk of infection by these diseases and others through fomites can be greatly reduced by simply washing one's hands.[6] When two children in one household have influenza, more than 50% of shared items are contaminated with virus. In 40–90% cases, adults infected with rhinovirus have it on their hands.[7]

Transmission of specific viruses

Researchers have discovered that smooth (non-porous) surfaces like door knobs transmit bacteria and viruses better than porous materials like paper money because porous, especially fibrous, materials absorb and trap the contagion, making it harder to contract through simple touch.[2] Nonetheless, fomites may include soiled clothes, towels, linens, handkerchiefs, and surgical dressings.[8][9]

SARS-CoV-2 was found to be viable on various surfaces from 4 to 72 hours under laboratory conditions.[10] However, further research called into question the accuracy of such tests, instead finding fomite transmission of SARS-Cov-2 in real world settings is extremely rare if not impossible.[11][12][13][14]

The 2007 research showed that the influenza virus was still active on stainless steel 24 hours after contamination. Though on hands it survives only for five minutes, the constant contact with a fomite almost certainly means catching the infection.[15] Transfer efficiency depends not only on surface, but mainly on pathogen type. For example, avian influenza survives on both porous and non-porous materials for 144 hours.[2]

Contaminated needles are the most common fomite that transmits HIV.[16] Fomites from dirty needles also easily spread Hepatitis B.[17]

Etymology

The Italian scholar and physician Girolamo Fracastoro appears to have first used the Latin word fomes, meaning "tinder", in this sense in his essay on contagion, De Contagione et Contagiosis Morbis, published in 1546:[18] "By fomes I mean clothes, wooden objects, and things of that sort, which though not themselves corrupted can, nevertheless, preserve the original germs of the contagion and infect by means of these".[19]

English usage of fomes, pronounced /ˈfoʊmiːz/, is documented since 1658.[20] The English word fomite, which has been in use since 1859, is a back-formation from the plural fomites (originally borrowed from the Latin plural fōmĭtēs [ˈfoːmɪteːs] of fōmĕs [ˈfoːmɛs]).[21][22] Over time, the English-language pronunciation of the plural fomites changed from /ˈfoʊmɪtiːz/) to /ˈfoʊmaɪts/, which led to the creation of a new singular fomite, pronounced /ˈfoʊmaɪt/.[22][23][24] The French fomite, Italian fomite, Spanish fómite and Portuguese fómite or fômite, however, are derived directly from the Latin accusative singular fōmĭtēm, as usually happens with Latin common nouns.

See also

References

  1. 1 2 Cramer, Lorraine (1 September 2011). "Fomites, fomites, fomites!". Microblogology. Archived from the original on 23 September 2020. Retrieved 8 March 2019.
  2. 1 2 3 Cook 2013, p. 208
  3. ↑ Bennett, Jarvis & Brachman 2007, p. 275
  4. ↑ McGovern, B.; Doyle, E.; Fenelon, L. E.; et al. (1 June 2010). "The necktie as a potential vector of infection: are doctors happy to do without?". Journal of Hospital Infection. 75 (2): 138–139. doi:10.1016/j.jhin.2009.12.008. ISSN 0195-6701. PMID 20299125. [...] in any care activity that involves contact with patients, as [neckties] serve no beneficial function in patient care, are rarely laundered and have been shown to be colonised by pathogens. Coagulase-negative staphylococci (CoNS) were found on two of five neckties of doctors working in an intensive care unit, and Staphylococcus aureus was isolated from eight of 40 doctors' ties in a Scottish hospital.
  5. ↑ Larson & Liverman 2011, pp. 41–42
  6. 1 2 Shaw, Michael (27 November 2006). "Never Heard Of Fomites? You'd Better Learn About Them!". gasdetection.com.
  7. ↑ Cook 2013, p. 207
  8. ↑ Abad, F. X.; R. M. Pintó; A. Bosch (October 1994). "Survival of enteric viruses on environmental fomites". Applied and Environmental Microbiology. 60 (10): 3704–10. doi:10.1128/AEM.60.10.3704-3710.1994. PMC 201876. PMID 7986043.
  9. ↑ Pope, Theodore W.; Peter T. Ender; William K. Woelk; Michael A. Koroscil; Thomas M. Koroscil (December 2002). "Bacterial contamination of paper currency". Southern Medical Journal. 95 (12): 1408–10. doi:10.1097/00007611-200295120-00011. PMID 12597308. S2CID 8477487.
  10. ↑ van Doremalen, Neeltje; Bushmaker, Trenton; Morris, Dylan H.; et al. (16 April 2020). "Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1". New England Journal of Medicine. 382 (16): 1564–1567. doi:10.1056/NEJMc2004973. ISSN 0028-4793. PMC 7121658. PMID 32182409.
  11. ↑ "COVID-19 rarely spreads through surfaces. So why are we still deep cleaning?". nature.
  12. ↑ "Low risk of SARS-CoV-2 transmission by fomites in real-life conditions". thelancet.com.
  13. ↑ Sobolik, J. S.; Sajewski, E. T.; Jaykus, L. A.; Cooper, D. K.; Lopman, B. A.; Kraay, A. N.; Ryan, P. B.; Guest, J. L.; Webb-Girard, A.; Leon, J. S. (2021). "Low risk of SARS-CoV-2 transmission via fomite, even in cold-chain". medRxiv : The Preprint Server for Health Sciences: 2021.08.23.21262477. doi:10.1101/2021.08.23.21262477. PMC 8404890. PMID 34462753.
  14. ↑ CDC (11 February 2020). "Coronavirus Disease 2019 (COVID-19)". Centers for Disease Control and Prevention. Retrieved 2 February 2022.
  15. ↑ Larson & Liverman 2011, p. 41
  16. ↑ Shors 2017, p. 279
  17. ↑ "Hepatitis B". mayoclinic.org.
  18. ↑ Nutton, Vivian (1990). "The Reception of Fracastoro's Theory of Contagion: The Seed That Fell among Thorns?". Osiris. University of Chicago Press. 2nd Series, Vol. 6, Renaissance Medical Learning: Evolution of a Tradition: 196–234. doi:10.1086/368701. JSTOR 301787. PMID 11612689. S2CID 37260514.
  19. ↑ Fracastoro, Girolamo (1961). "Contagion, contagious diseases and their treatment (1546)". In Brock, Thomas D. (ed.). Milestones in Microbiology. Translated by Wright, Wilmer C. Prentice-Hall International. pp. 69–75. Retrieved 10 August 2013.
  20. ↑ "fomes". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  21. ↑ Fortuine 2000, p. 53
  22. 1 2 "fomite". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  23. ↑ "fomite". Merriam-Webster's Online Dictionary. Merriam-Webster.
  24. ↑ "Language Log: Fomite: panacea or backformation?". itre.cis.upenn.edu.

Bibliography

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