Human-to-human transmission

Human-to-human transmission (HHT) is an epidemiologic vector, ^[a] especially in case the disease is borne by individuals known as superspreaders. In these cases, the basic reproduction number of the virus, which is the average number of additional people that a single case will infect without any preventative measures, can be as high as 203.9. ^{[9] [10]} Interhuman transmission is a synonym for HHT. ^[11]

The World Health Organization designation of a pandemic hinges on the demonstrable fact that there is sustained HHT in two regions of the world. ^[12]

Synopsis

Relevant microbes may be viruses, bacteria, or fungi, and they may be spread through breathing, talking, coughing, sneezing, spraying of liquids, toilet flushing or any activities which generate aerosol particles or droplets or generate fomites, such as raising of dust. ^{[13] [14]}

Transfer efficiency depends not only on surface, but also on pathogen type. For example, avian influenza survives on both porous and non-porous materials for 144 hours. ^[13]

The microbes may also be transmitted by poor use of cutlery or improper sanitation of dishes or bedlinen. Particularly problematic are toilet practices, which lead to the fecal–oral route. STDs are by definition spread through this vector.^{[ citation needed ]}

List of HHT diseases

Examples of some HHT diseases are listed below.^{[ citation needed ]}

• measles: vaccine available
• mumps: vaccine available
• chicken pox: vaccine available
• small pox ^[15]
• bubonic plague: slim non-nil risk ^[16]
• pneumonic plague: 1910-11 Manchurian plague ^[17]
• tuberculosis
• Norovirus ^{[18] [19]}
• monkeypox ^[20]
• SARS-CoV-1
• SARS-CoV-2: vaccine available
• MERS
• Avian flu
• Sexually transmitted infections (STIs) or sexually transmitted diseases (STDs):
  • Syphilis, aka French pox ^[15]

Notes

1. Attributed to multiple references: ^{[1] [2] [3] [4] [5] [6] [7] [8]}

References

1. Chowell G, Blumberg S, Simonsen L, Miller MA, Viboud C (2014). "Synthesizing data and models for the spread of MERS-CoV, 2013: Key role of index cases and hospital transmission". Epidemics. 9: 40–51. doi:10.1016/j.epidem.2014.09.011. PMC   4258236 . PMID   25480133.
2. Virlogeux V, Feng L, Tsang TK, Jiang H, Fang VJ, Qin Y, Wu P, Wang X, Zheng J, Lau EH, Peng Z, Yang J, Cowling BJ, Yu H (2018). "Evaluation of animal-to-human and human-to-human transmission of influenza A (H7N9) virus in China, 2013–15". Scientific Reports. 8 (1): 552. Bibcode:2018NatSR...8..552V. doi:10.1038/s41598-017-17335-9. PMC   5765021 . PMID   29323268.
3. Majumder MS, Brownstein JS, Finkelstein SN, Larson RC, Bourouiba L (2017). "Nosocomial amplification of MERS-coronavirus in South Korea, 2015". Transactions of the Royal Society of Tropical Medicine and Hygiene. 111 (6): 261–269. doi:10.1093/trstmh/trx046. PMC   6257029 . PMID   29044371.
4. De Graaf M, Beck R, Caccio SM, Duim B, Fraaij PL, Le Guyader FS, Lecuit M, Le Pendu J, De Wit E, Schultsz C (2017). "Sustained fecal-oral human-to-human transmission following a zoonotic event". Current Opinion in Virology. 22: 1–6. doi:10.1016/j.coviro.2016.11.001. PMC   7102779 . PMID   27888698.
5. Geoghegan JL, Senior AM, Di Giallonardo F, Holmes EC (2016). "Virological factors that increase the transmissibility of emerging human viruses". Proceedings of the National Academy of Sciences. 113 (15): 4170–4175. Bibcode:2016PNAS..113.4170G. doi: 10.1073/pnas.1521582113 . PMC   4839412 . PMID   27001840.
6. Kucharski A, Mills H, Pinsent A, Fraser C, Van Kerkhove M, Donnelly CA, Riley S (2014). "Distinguishing Between Reservoir Exposure and Human-to-Human Transmission for Emerging Pathogens Using Case Onset Data". PLOS Currents. 6. doi: 10.1371/currents.outbreaks.e1473d9bfc99d080ca242139a06c455f (inactive 12 July 2025). PMC   3946006 . PMID   24619563.
7. Herfst S, Böhringer M, Karo B, Lawrence P, Lewis NS, Mina MJ, Russell CJ, Steel J, De Swart RL, Menge C (2017). "Drivers of airborne human-to-human pathogen transmission". Current Opinion in Virology. 22: 22–29. doi:10.1016/j.coviro.2016.11.006. PMC   7102691 . PMID   27918958.
8. Riou J, Althaus CL (2020). "Pattern of early human-to-human transmission of Wuhan 2019 novel coronavirus (2019-nCoV), December 2019 to January 2020". Eurosurveillance. 25 (4). doi:10.2807/1560-7917.ES.2020.25.4.2000058. PMC   7001239 . PMID   32019669.
9. Li Q, Guan X, Wu P, Wang X, Zhou L, Tong Y, et al. (January 2020). "Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus-Infected Pneumonia". The New England Journal of Medicine. 382 (13): 1199–1207. doi: 10.1056/NEJMoa2001316 . PMC   7121484 . PMID   31995857.
10. Riou J, Althaus CL (January 2020). "Pattern of early human-to-human transmission of Wuhan 2019 novel coronavirus (2019-nCoV), December 2019 to January 2020". Euro Surveillance. 25 (4). doi:10.2807/1560-7917.ES.2020.25.4.2000058. PMC   7001239 . PMID   32019669.
11. Meyer A, Esposito JJ, Gras F, Kolakowski T, Fatras M, Muller G (1991). "First appearance of monkey pox in human beings in Gabon". Médecine Tropicale: Revue du Corps de Santé Colonial. 51 (1): 53–7. PMID   1649373.
12. Friscolanti M (4 June 2009). "Canada's Pandemic Influenza Plan". Canadian Encyclopedia.
13. Cook 2013, p. 208.
14. Abad FX, 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.
15. Welford MR, Bossak BH, Carter DA (22 December 2009). "Validation of Inverse Seasonal Peak Mortality in Medieval Plagues, Including the Black Death, in Comparison to Modern Yersinia pestis-Variant Diseases". PLOS ONE. 4 (12): e8401. Bibcode:2009PLoSO...4.8401W. doi: 10.1371/journal.pone.0008401 . PMC   2791870 . PMID   20027294.
16. Kool JL (2005). "Risk of Person-to-Person Transmission of Pneumonic Plague". Clinical Infectious Diseases. 40 (8): 1166–1172. doi: 10.1086/428617 . PMID   15791518.
17. Wilson M (24 March 2020). "The untold origin story of the N95 mask". Fast Company.
18. Kumar Nag P (2018). Office Buildings: Health, Safety and Environment. Springer. p. 85. ISBN   978-981-13-2577-9.
19. Robilotti E, Deresinski S, Pinsky BA (2015). "Norovirus". Clinical Microbiology Reviews. 28 (1): 134–164. doi:10.1128/CMR.00075-14. PMC   4284304 . PMID   25567225.
20. Learned LA, Reynolds MG, Wassa DW, Li Y, Olson VA, Karem K, Stempora LL, Braden ZH, Kline R, Likos A, Libama F, Moudzeo H, Bolanda JD, Tarangonia P, Boumandoki P, Formenty P, Harvey JM, Damon IK (2005). "Extended interhuman transmission of monkeypox in a hospital community in the Republic of the Congo, 2003". The American Journal of Tropical Medicine and Hygiene. 73 (2): 428–34. doi: 10.4269/ajtmh.2005.73.428 . PMID   16103616.

Sources

• Cook N (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.
• Larson EL, Liverman CT (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.