(originally) any morbid matter or morbific agent that is difficult to detect (cf. virus, n. 2a); (in later use) spec. any virus (virus, n. 2b)…

The causative agent of influenza; (in later use) spec. any orthomyxovirus of the genera Influenzavirus A, Influenzavirus B, and Influenzavirus C.

Originally: the causative agent of cowpox or smallpox. In later use: spec. any member of a group (now the family Poxviridae) of large, enveloped…

a substance or organism capable of passing through a filter; spec. a filterable virus.

a virus causing mosaic disease; cf. tobacco mosaic virus n. at tobacco, n. compounds 4.

A minute organism or agent which destroys bacteria. Cf. phage, n.

(also as one word), any of a group of related viruses that includes those causing shingles and chicken-pox, esp. Herpesvirus hominis, the cause of…

the retrovirus that causes Rous sarcoma; abbreviated RSV.

= Rous sarcoma virus n.

Originally: any of several viruses that cause the formation of warts (papillomas). In later use: spec. any member of the genus Papillomavirus…

A virus that causes poliomyelitis; spec. a human virus belonging to the genus Enterovirus (family Picornaviridae) that causes most cases of…

Used attributively in Semliki Forest virus n. an insect-borne togavirus used extensively as an experimental organism in genetic research.

A virus that attacks actinomycetes.

Microbiology. A mycovirus.

A picornavirus originally found in monkeys but capable of infecting other species, the infection in humans being characterized by encephalomyelitis.

a virus that causes tumours.

A mosquito-borne flavivirus, originally identified in African monkeys but increasingly affecting human populations, which can cause symptoms…

Any bacteriophage that infects mycobacteria.

an insect-borne togavirus, related to Semliki Forest virus and also used extensively in genetic research. Also absol.

(In form Myxovirus) a group of viruses including the influenza viruses and other viruses with similar morphology and reactions with mucoproteins (now…

Any of a group of human enteroviruses which typically cause mild or asymptomatic infections.

a virus in which the genetic material is RNA rather than DNA.

Any of a group (formerly the genus Adenovirus, now the family Adenoviridae) of non-enveloped, double-stranded DNA viruses which are pathogens of…

Simian virus: used, frequently with following numeral to identify the strain, as the designation of various viruses isolated from monkeys or cultures…

= arbovirus, n.

Any of a group (now the genus Enterovirus) of picornaviruses that primarily infect the gastrointestinal tract of humans and other mammals but which…

Any of a group (now the genus Spumavirus) of retroviruses which infect a number of mammal species (including humans), and which induce the formation…

any of a small group (now the genus Pneumovirus) of paramyxoviruses that cause syncytium formation in infected cells, and include several which…

= polyomavirus, n. Frequently attributive.

More fully parainfluenza virus: any of several species of paramyxovirus (genus Respirovirus) that cause respiratory infections in man and certain…

Any member of the family Reoviridae of non-enveloped, double-stranded RNA viruses with a segmented genome and (usually) a double capsid…

Any of a large group of RNA viruses which are transmitted to vertebrates by blood-feeding arthropods such as mosquitoes and ticks; spec. a virus…

Any of a group of herpesviruses which are species-specific pathogens of humans and various other mammals, and which produce distinctive enlargement…

tobacco mosaic virus.

vacuolating agentor virus: a papovavirus, originally obtained from rhesus monkey kidney tissue, which is capable of causing tumours in animals…

Any member of the genus Rhinovirus, comprising picornaviruses which cause the common cold and other upper respiratory infections in humans. Also (in…

= respiratory syncytial virus n. at respiratory, adj. compounds.

Any member of a group of viruses (usually regarded as the family Papovaviridae) comprising the papillomaviruses and polyomaviruses, which are small…

Any member of a group (now the family Paramyxoviridae) of enveloped, single-stranded RNA viruses which have a non-segmented genome and envelope…

Any member of the family Picornaviridae of very small, non-enveloped, single-stranded RNA viruses which are pathogens of mammals and birds, and…

Microbiology. A mycobacteriophage. rare.

Virology. Any member of the genus Parvovirus of very small, non-enveloped, single-stranded DNA viruses which are pathogens of mammals and birds…

Any member of a group (now the family Rhabdoviridae) of bullet- or rod-shaped, enveloped, single-stranded RNA viruses which include rabies virus…

a mosquito-borne alphavirus endemic in parts of Australia and certain Pacific islands, causing epidemics of a human disease characterized by…

Any member of a group (formerly a genus) of enveloped, single-stranded RNA viruses which have prominent projections from the envelope and are…

Epstein-Barr virus.

An enveloped DNA herpes virus which causes infectious mononucleosis and is associated with Burkitt's lymphoma and nasopharyngeal carcinoma.

= retrovirus, n.

cytomegalovirus.

= arenavirus, n.

Any retrovirus that causes malignant disease (leukaemia, lymphoma, carcinoma, etc.).

Any member of the family Togaviridae of enveloped, single-stranded RNA viruses, including the alphaviruses and rubella virus (genus Rubivirus).

Any member of the genus Alphavirus of antigenically related togaviruses that infect a wide range of mammals, birds, and other vertebrates, are…

Any of a group (formerly the genus Calicivirus, now the family Caliciviridae) of non-enveloped, single-stranded RNA viruses which have a capsid…

A spherical particle found in the blood of patients with hepatitis B, now recognized as the capsulated form of the virus responsible for the disease.

Any member of the genus Flavivirus of enveloped, single-stranded RNA viruses, most of which are arthropod-borne pathogens of mammals and birds…

= flavivirus, n.

In full maedi virus. = maedi-visna virus n. at compounds. Now rare.

Any member of the genus Orbivirus, comprising reoviruses with distinctive ring-shaped capsomeres, which are arthropod-borne pathogens of mammals…

A virus that infects fungi.

infection of sheep or goats by the visna-maedi virus, a lentivirus which may give rise to visna or maedi; cf. maedi-visna n. at maedi, n. compounds.

= influenza virus, n.

the lentivirus that causes maedi and visna; also called visna-maedi virus, visna virus (cf. sense 2).

A coronavirus; (now) esp. that which causes Covid-19. Also: infection with or disease caused by a coronavirus; (now) esp. Covid-19. Frequently as a…

Any member of the genus Orthopoxvirus, comprising serologically related poxviruses which infect various species of mammal and cause typical pox…

Any member of the genus Rotavirus of wheel-shaped reoviruses which are pathogens of a wide range of mammals and birds, typically causing severe…

More fully whitepox virus. A virus isolated from monkey tissue, originally believed to be a new orthopoxvirus but later recognized to be smallpox…

= retrovirus, n.

a tropical African filovirus known to infect humans and certain other primates, causing epidemics of severe, usually fatal haemorrhagic fever in…

Any member of the genus Morbillivirus of serologically closely related paramyxoviruses which cause the formation of intranuclear inclusions, and…

Any member of the family Retroviridae of enveloped, single-stranded RNA viruses possessing the enzyme reverse transcriptase, which allows…

Ebola virus; Ebola fever.

Any member of a group (now the genus Lentivirus) of non-oncogenic retroviruses which includes the viruses responsible for certain slow virus…

A reassortant virus.

human T-cell lymphotropic or lymphocyte virus: any of several retroviruses (HTLV-1, HTLV-2, etc.) of which one at least (HTLV-3, also called HIV-1)…

= morbillivirus, n. Frequently attributive, esp. in morbilli group.

Any member of the family Filoviridae of enveloped, single-stranded RNA viruses with pleomorphic filamentous particles, which cause severe, often…

lymphadenopathy-associated virus (a former name for the virus now called HIV-3).

A coronavirus; (now) esp. the coronavirus which causes the disease Covid-19. Also: the disease Covid-19.

Human immunodeficiency virus, a retrovirus (genus Lentivirus) which chronically infects cells of the human immune system and causes AIDS, and…

= sense 1.

The disease Covid-19; (also) the coronavirus which causes this. Frequently as a modifier, as in C-19 pandemic, C-19 virus, etc.

The disease Covid-19; (also) the coronavirus which causes this. Frequently as a modifier, as in Covid case, Covid crisis, Covid patient, etc. Cf. Cov…

An acute disease in humans caused by a coronavirus, which is characterized mainly by fever and cough and is capable of progressing to pneumonia…

The disease Covid-19; (also) the coronavirus which causes this. Frequently as a modifier, as in CV-19 pandemic, CV-19 virus, etc.