Editing Pathogen transmission (section)

{{Short description|Passing of a pathogen from one organism to another}}
{{cs1 config|name-list-style=vanc}}
{{About|transmission of disease-causing pathogens|other uses| Transmission (disambiguation){{!}} Transmission |}}
{{Use dmy dates|date=May 2020}}
In [[medicine]], [[public health]], and [[biology]], '''transmission''' is the passing of a [[pathogen]] causing [[Infectious disease|communicable disease]] from an infected [[host (biology)|host]] individual or group to a particular individual or group, regardless of whether the other individual was previously infected.<ref>{{cite book | vauthors = Bush AO, Fernández JC, Esch GW, Seed JR |title=Parasitism: The Diversity and Ecology of Animal Parasites |date=2001 |publisher=Cambridge University Press |location=Cambridge, UK |isbn=9780521664479 |pages=391–399}}</ref> The term strictly refers to the transmission of [[microorganism]]s directly from one individual to another by one or more of the following means:<!--cited in body of article-->
* [[airborne transmission]] – very small dry and wet particles that stay in the air for long periods of time allowing airborne contamination even after the departure of the host.  Particle size < 5 [[μm]].
* [[Respiratory droplet|droplet transmission]] – small and usually wet particles that stay in the air for a short period of time. Contamination usually occurs in the presence of the host. Particle size > 5 μm.
* direct physical contact – touching an infected individual, including sexual contact
* indirect physical contact – usually by touching a contaminated surface, including [[soil]] ([[fomite]])
* [[fecal–oral route|fecal–oral transmission]] – usually from unwashed hands, contaminated food or water sources due to lack of [[sanitation]] and [[hygiene]], an important transmission route in pediatrics, veterinary medicine and developing countries.
* via contaminated hypodermic needles or blood products

Transmission can also be indirect, via another [[organism]], either a [[Vector (epidemiology)|vector]] (e.g. a [[mosquito]] or fly) or an intermediate host (e.g. [[Taenia solium|tapeworm in pigs]] can be transmitted to humans who ingest improperly cooked [[pork]]). Indirect transmission could involve [[zoonosis|zoonoses]] or, more typically, larger pathogens like [[macroparasite]]s with more complex [[Biological life cycle|life cycle]]s. Transmissions can be [[autochthonous transmission|autochthonous]] (i.e. between two individuals in the same place) or may involve travel of the microorganism or the affected hosts.

A 2024 World Health Organization report standardized the terminology for the transmission modes of all respiratory pathogens in alignment with particle physics: airborne transmission; inhalation; direct deposition; and contact.<ref name=":4">{{Cite journal |last=Leung |first=Nancy H. L. |last2=Milton |first2=Donald K. |date=2024-07-03 |title=New WHO proposed terminology for respiratory pathogen transmission |url=https://www.nature.com/articles/s41579-024-01067-5 |journal=Nature Reviews Microbiology |language=en |pages=1–2 |doi=10.1038/s41579-024-01067-5 |issn=1740-1534|url-access=subscription }}</ref> But these newly standardized terms have yet to be translated to policy, including infection control policy<ref name=":4" /> or the pandemic accords or updated International Health Regulations.