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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.

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. Contamination can occur when one of these objects comes into contact with bodily secretions, like nasal fluid, vomit or feces from landed toilet flushing aerosols (Toilet Plume). 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. Fomites such as splinters, barbed wire or farmyard surfaces, including soil, feeding troughs or barn beams, have been implicated as sources of virus.

Hospital fomites

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

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. 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. 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. The risk of infection by these diseases and others through fomites can be greatly reduced by simply washing one's hands. 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.

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. Nonetheless, fomites may include soiled clothes, towels, linens, handkerchiefs, and surgical dressings.

SARS-CoV-2 was found to be viable on various surfaces from 4 to 72 hours under laboratory conditions. On porous surfaces, studies report inability to detect viable virus within minutes to hours; on non-porous surfaces, viable virus can be detected for days to weeks. 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.

Contact with aerosolized virus (large droplet spread) generated via talking, sneezing, coughing, or vomiting, toilet flushing & produced toilet plume or contact with airborne virus that settles after disturbance of a contaminated fomite (e.g. shaking a contaminated blanket). During the first 24 hours, the risk can be reduced by increasing ventilation and waiting as long as possible before entering the space (at least several hours, based on documented airborne transmission cases), and using personal protective equipment (including any protection needed for the cleaning and disinfection products) to reduce risk.

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. 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.

Smallpox was long supposed to be transmitted either by direct contact or by fomites. However A. R. Rao’s careful researches in the 1960s, before smallpox was declared extinct, found little truth in the traditional belief that smallpox can be spread at a distance through infected clothing or bedding. He concluded that it normally invaded via the lungs. Rao recognized that the virus can be detected on inanimate objects, and therefore might in some cases be transmitted by them, but he concluded that “smallpox is still an inhalation disease . . . the virus has to enter through the nose by inhalation.”

In 2002 Donald K. Milton published a review of existing research upon the transmission of smallpox and upon recommendations for controlling its spread in the event of its use in biological war. He agreed, citing Rao, Fenner and others, that “careful epidemiologic investigation rarely implicated fomites as a source of infection”; and broadly agreed with current recommendations for control of secondary smallpox infections, which emphasized transmission via “expelled droplets” upon the breath. He noted that shed scabs (which might be spread via bedsheets or other fomites) often contain “large quantities of virus”, but suggested that the “apparent lack of infectiousness of scab associated virus” might be due to “encapsulation with inspissated pus”.

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

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: "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".

English usage of fomes, pronounced /ˈfoʊmiːz/, is documented since 1658. 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]). 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/.

In Latin, fomes (genitive: fomitis, plural fomites, stem fomit-) is a third-declension T-stem noun. Such nouns, like miles/militis or comes/comitis, typically lose their T (thereby becoming a syllable shorter) in the nominative singular, but retain it in all other cases. In languages derived from Latin, the French fomite, Italian fomite, Spanish fómite and Portuguese fómite or fômite, retain the full stem.

See also

• Focal infection theory
• Focus of infection
• Disease vector

References

1. ^ Cramer, Lorraine (1 September 2011). "Fomites, fomites, fomites!". Microblogology. Archived from the original on 23 September 2020. Retrieved 8 March 2019.
2. ^ "Coronavirus Disease 2019 (COVID-19)". 11 February 2020.
3. Kraay ANM; Hayashi MAL; Berendes, D. M.; Sobolik, J. S.; Leon, J. S.; Lopman, B. A. (2021). "Risk for Fomite-Mediated Transmission of SARS-CoV-2 in Child Daycares, Schools, Nursing Homes, and Offices". Emerging Infectious Diseases. 27 (4): 1229–1231. doi:10.3201/eid2704.203631. PMC 8007300. PMID 33755002.
4. Lawrence, Philip; Danet, Nicolas; Reynard, Olivier; Volchkova, Valentina; Volchkov, Viktor (February 2017). "Human transmission of Ebola virus". Current Opinion in Virology. 22: 51–58. doi:10.1016/j.coviro.2016.11.013. PMID 28012412.
5. Bennett, Jarvis & Brachman 2007, p. 275
6. 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 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.
7. Larson & Liverman 2011, pp. 41–42
8. ^ Boone, Stephanie A.; Gerba, Charles P. (2007). "Significance of Fomites in the Spread of Respiratory and Enteric Viral Disease". Applied and Environmental Microbiology. 73 (6): 1687–1696. Bibcode:2007ApEnM..73.1687B. doi:10.1128/AEM.02051-06. PMC 1828811. PMID 17220247.
9. ^ Shaw, Michael (27 November 2006). "Never Heard Of Fomites? You'd Better Learn About Them!". gasdetection.com.
10. Cook 2013, p. 207
11. ^ Cook 2013, p. 208
12. 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. Bibcode:1994ApEnM..60.3704A. doi:10.1128/AEM.60.10.3704-3710.1994. PMC 201876. PMID 7986043.
13. 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.
14. 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.
15. Lewis, Dyani (2021). "COVID-19 rarely spreads through surfaces. So why are we still deep cleaning?". Nature. 590 (7844): 26–28. Bibcode:2021Natur.590...26L. doi:10.1038/d41586-021-00251-4. PMID 33514939. S2CID 231765058.
16. Mondelli, Mario U.; Colaneri, Marta; Seminari, Elena M.; Baldanti, Fausto; Bruno, Raffaele (2021). "Low risk of SARS-CoV-2 transmission by fomites in real-life conditions". The Lancet Infectious Diseases. 21 (5): e112. doi:10.1016/S1473-3099(20)30678-2. PMC 7524520. PMID 33007224. S2CID 222002135.
17. 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 10.1101/2021.08.23.21262477.
18. CDC (11 February 2020). "Coronavirus Disease 2019 (COVID-19)". Centers for Disease Control and Prevention. Retrieved 2 February 2022.
19. New study shows what happens when we flush a lidless toilet | CNN. 19 December 2022. Retrieved 9 November 2024 – via www.cnn.com.
20. Larson & Liverman 2011, p. 41
21. A.R. Rao, Smallpox, KBD, Bombay, 1972, pp.86-89, 91-92, and 95.
22. Rao, p. 88.
23. Donald K. Milton (29 November 2012). "What was the primary mode of smallpox transmission? Implications for biodefense". Front Cell Infect Microbiol. 2 (150): 150. doi:10.3389/fcimb.2012.00150. PMC 3509329. PMID 23226686.
24. Shors 2017, p. 279
25. "Hepatitis B". mayoclinic.org.
26. Nutton, Vivian (1990). "The Reception of Fracastoro's Theory of Contagion: The Seed That Fell among Thorns?". Osiris. 2nd Series, Vol. 6, Renaissance Medical Learning: Evolution of a Tradition. University of Chicago Press: 196–234. doi:10.1086/368701. JSTOR 301787. PMID 11612689. S2CID 37260514.
27. 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.
28. "fomes". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
29. Fortuine 2000, p. 53
30. ^ "fomite". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
31. "fomite". Merriam-Webster's Online Dictionary. Merriam-Webster. 16 June 2023.
32. "Language Log: Fomite: panacea or backformation?". itre.cis.upenn.edu.

Bibliography

• Cook, Nigel (2013), "10.1 Introduction; the role of fomites in the virus transmission", Viruses in Food and Water: Risks, Surveillance and Control, Cambridge: Woodhead Publishing, pp. 205–215, ISBN 978-0-85709-887-0
• Bennett, John V.; Jarvis, William Robert; Brachman, Philip S. (2007), "Chapter 19: The Inanimate Environment", Bennett & Brachman's Hospital Infections, Philadelphia: Lippincott Williams & Wilkins, p. 277, ISBN 978-0-7817-6383-7
• Fortuine, Robert (2000), The Words of Medicine: Sources, Meanings, and Delights, Springfield: Charles C Thomas Publisher, p. 53, ISBN 0398071322
• Larson, Elaine L.; Liverman, Catharyn T. (2011), "Understanding the Risk to Healthcare Personnel: Fomite Persistence", Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Personnel: Update 2010, Washington: National Academies Press, p. 41, ISBN 978-0-309-16254-8
• Shors, Teri (2017), "Clinical Signs and Symptoms of Human Herpersviruses", Understanding Viruses, Wisconsin: Jones & Bartlett Learning, ISBN 978-1-284-02592-7

External links

• General characteristics and roles of fomites in viral transmission, American Society for Microbiology, 1969 Archived 24 April 2010 at the Wayback Machine

• Infectious diseases
• Epidemiology
• Hygiene
• Medical terminology