In medicine,<unk> is the passing of a disease from an infected individual or group to a previously uninfected individual or group.
The microorganisms (bacteria and viruses) that cause disease may be transmitted from one person to another by one or more of the following means:
droplet contact - coughing or sneezing on another person
direct physical contact - touching an infected person, including sexual contact
indirect contact - usually by touching soil contamination or a contaminated surface
airborne<unk> - if the microorganism can remain in the air for long periods
fecal-oral<unk> - usually from contaminated food or water sources
vector borne<unk> - carried by insects or other animals
Microorganisms vary widely in the length of time that they can survive outside the human body, and so vary in how they are transmitted.
Transmission 
Dosing
Utilization behavior
Perspiration
Penetrance
Presentation 
Surface science
Residency 