S: NEA – http://cort.as/-Cr0e (last access: 9 December 2018); NCBI – https://bit.ly/2Uwc39Y (last access: 9 december 2018).
N: 1. – infectious (adj): “catching, having the quality of spreading from person to person, communicable by infection,” 1540s of diseases, 1610s of emotions, actions, etc.; see infection (late 14c., “infectious disease; contaminated condition;” from Old French infeccion “contamination, poisoning” (13c.) and directly from Late Latin infectionem, nominative infectio, “infection, contagion”) + -ous (word-forming element making adjectives from nouns, meaning “having, full of, having to do with, doing, inclined to,” from Old French -ous, -eux, from Latin -osus). Earlier in the same sense were infectuous (late 15c.), infective (late 14c.). Related: Infectiously; infectiousness.
– disease (n): early 14c., “discomfort, inconvenience, distress, trouble,” from Old French desaise “lack, want; discomfort, distress; trouble, misfortune; disease, sickness,” from des- “without, away” + aise “ease”. Restricted pathological sense of “sickness, illness” in English emerged by late 14c.; the word still sometimes was used in its literal sense early 17c., and was somewhat revived 20c., usually with a hyphen (dis-ease).
2. Infectious disease, in medicine, a process caused by a microorganism that impairs a person’s health. An infection, by contrast, is the invasion of and replication in the body by any of various microbial agents—including bacteria, viruses, fungi, protozoans, and worms—as well as the reaction of tissues to their presence or to the toxins that they produce. When health is not altered, the process is termed a subclinical infection. Thus, a person may be infected but not have an infectious disease. This principle is illustrated by the use of vaccines for the prevention of infectious diseases. For example, a virus such as that which causes measles may be attenuated (weakened) and used as an immunizing agent. The immunization is designed to produce a measles infection in the recipient but generally causes no discernible alteration in the state of health. It produces immunity to measles without producing a clinical illness (an infectious disease).
3. The etiologic agent may be a bacterium, virus, fungus, or animal parasite, and may be transmitted from another host or arise from the host’s own indigenous microflora.
4. Examples of infectious diseases are HIV, hepatitis, influenza, C. difficile, West Nile virus and Creutzfeldt-Jakob disease.
S: 1. OED – https://bit.ly/2B0vUVE; https://bit.ly/2QlnAtX (last access: 9 december 2018). 2. EncBrit – https://bit.ly/2QGe6ZJ (last access: 9 december 2018). 3 & 4. TERMIUM PLUS – https://bit.ly/2EaHhxm (last access: 9 december 2018).
CR: dengue, HIV, transmissible disease.