infectious, a.
(ɪnˈfɛkʃəs)
[f. infect-ion + -ious; cf. mod.F. infectieux. An earlier formation after L. infectu-s was infectuous.]
1. a. Having the quality or power of communicating disease by infection; infecting with disease; pestilential, unhealthy.
| 1542 Boorde Dyetary xxvii. (1870) 290 Whan the Plages of the Pestylence or the swetynge syckenes is in a towne or countree..the people doth fle from the contagious and infectious ayre. Ibid., In such infectious tyme. 1602 Marston Antonio's Rev. iv. iii, Why permit you now such scum..to..taint the ayre With his infectious breath? 1774 Goldsm. Nat. Hist. I. 195 It would seem that the predominance of any one vapour..becomes infectious, and that we owe the salubrity of the air to the variety of its mixture. 1829 Lytton Devereux ii. ii, There is something infectious in the atmosphere. 1838 Penny Cycl. XII. 470/2 The infectious qualities of substances which cannot be conveniently washed. |
† b. Poisonous. Obs. rare—1.
| 1658 Rowland Moufet's Theat. Ins. 909 On the trees..there growes a kinde of infectious honey. The which poyson being drank makes men stupid, and out of their wits. |
2. a. Of diseases: Apt to be communicated or received by infection; liable to be transmitted from one person to another by means of air or water (in strict use, distinguished from contagious, q.v.).
| 1592 Shakes. Rom. & Jul. v. ii. 10 In a house Where the infectious pestilence did raigne. 1610 Bp. Hall Recoll. Treat. (1614) 754 Leprosie or plague..diseases, not more deadly then infectious. 1683 Burnet tr. More's Utopia (1684) 93 That such of them as are sick of infectious Diseases, may be kept so far from the rest, that there can be no danger of Contagion. 1790 Beatson Nav. & Mil. Mem. II. 13 The fever was highly infectious, and swept off great numbers. 1897 Allbutt's Syst. Med. II. 252 Its virus is incapable of diffusion in the atmosphere, and..consequently it is contagious only and not infectious also. |
b. transf. Of or for infectious diseases.
| 1887 Pall Mall G. 5 Oct. 9/1 Typhoid is prevalent..and several cases are now being treated at the infectious hospital. 1894 Lancet 3 Nov. 1064 The infectious hospital is that of St. Ladislaus. |
c. In the names of various diseases, as infectious hepatitis, an acute infectious virus disease characterized by hepatitis and jaundice; infectious mononucleosis, an acute disease (also called glandular fever) chiefly affecting young adults, characterized by fever, swelling of the lymph nodes, and leucocytosis.
| 1920 Sprunt & Evans in Bull. Johns Hopkins Hosp. XXXI. 410 (heading) Mononuclear leucocytosis in reaction to acute infections (‘infectious mononucleosis’). 1945 Amer. Jrnl. Med. Sci. CCX. 561 (heading) Homologous serum hepatitis and infectious (epidemic) hepatitis. 1970 Passmore & Robson Compan. Med. Stud. II. xviii. 117/1 Infectious hepatitis is usually spread by faecal contamination from a patient or convalescent carrier of the disease. 1970 A. J. Zuckerman Virus Dis. Liver xiii. 149 Infectious mononucleosis is an endemic disease affecting principally adolescents and young adults. |
† 3. Infected with disease. Obs.
| 1542 Boorde Dyetary xvii. (1870) 290 The syckenes is taken with the sauour of a mans clothes the which hath vysyted the infectious howse. 1604 Shakes. Oth. iv. i. 21 It comes ore my memorie As doth the Rauen o're the infectious [Qos. infected] house Boading to all. 1618 Rowlands Sacr. Mem. Mirac. 41 Are there not ten infectious creatures cleane, Of whom this poore Samaria stranger, meane, Onely returns? 1727 Bradley Fam. Dict. s.v. Canker, Incorporate the whole together with Vinegar..and rubbing the infectious Place therewith, it will cure them. |
4. Tending or liable to infect or contaminate character, morals, etc. Now rare.
| 1547–64 Bauldwin Mor. Philos. (Palfr.) To Rdr., That pestilent and most infectious canker, idlenesse. 1685 Baxter Paraphr. N.T., Matt. xviii. 15, etc., To keep Christians from the snare and the shame of infectious and wicked Associates. 1742 Young Nt. Th. v. 142 The world's infectious; few bring back at eve, Immaculate, the manners of the morn. |
5. Of actions, emotions, etc.: Having the quality of spreading from one to another; ‘catching’, contagious.
| a 1611 Beaum. & Fl. Maid's Trag. i. i, She carries with her an infectious grief, That strikes all her beholders. 1700 Dryden Palamon & Arc. ii. 313 Through the bright quire th' infectious virtue ran. All dropt their tears. 1828 Whately Rhet. in Encycl. Metrop. 300/1 Almost every one is aware of the infectious nature of any emotion excited in a large assembly. 1866 G. Macdonald Ann. Q. Neighb. xi. (1878) 200 How hearty and infectious his laughter! 1899 Nation (N.Y.) 12 Oct. 275/2 An infectious good humour and urbanity. |
6. Internat. Law. Tainting with illegality (said of contraband or hostile goods in their effect on the rest of a cargo, or on the ship); cf. infect v. 6 b.
| 1878 Kent Internat. Law ix. (ed. 2) 339 Contraband articles are said to be of an infectious nature, and they contaminate the whole cargo belonging to the same owners. |