Mammalian type B oncovirus group

Betaretrovirus.

'Mammalian type B retroviruses' A former genus in the family Retroviridae, now named Betaretrovirus.

'Mammalian type C retroviruses' A former genus of the family Retroviridae, now named Gammaretrovirus.

Mammalian virus group A subgroup of the genus Gammaretrovirus containing six replication-competent viruses and eight replication-defective sarcoma-inducing viruses (see Table M1). The genome is single-stranded RNA, 8.3kb in length, and the tRNA primer is tRNAPro. The LTR is about 600 bases in length (U3-500, R-60, U5-75). There are two cross-reacting antigens: those shared by virus from one host species (gs-1 species-specific antigens) and those shared by different virus species from different mammalian hosts. There are two interspecies antigens, a and b, both present in the mouse virus, but in the feline, porcine and woolly monkey viruses there is only b. The sarcoma virus genomes contain addi tional genetic information (oncogene) which, when integrated into a host cell, causes transformation to a neoplastic cell, but they may lack the information to make their coat proteins and are then defective, being unable to produce infective virus particles without the help of the leukemogenic viruses. The helper virus provides the coat proteins and thus determines the host range of the progeny sarcoma virus. Not all type C viruses are oncogenic since they may lack the onco-gene. The genetic information of some type C viruses, the virogene, which may or may not contain the oncogene, is present in all the cells of many species of animal. These virogenes are replicated with the cell genetic material. The viro-gene on activation can produce a virus which may or may not be oncogenic. The role of these viruses in the development of spontaneous tumors is not clear. Laboratory strains of C-type oncoviruses replicate and produce much free virus: they are 'exogenous'. In contrast, the integrated C-type oncoviruses only appear as virus particles on activation and are termed 'endogenous'. When produced they may be detected by electron microscopy, by the presence of their reverse transcriptase or other viral proteins, and by nucleic acid hybridization. They may be ecotropic (replicating only in the species of origin), xenotropic (unable to replicate in the species of origin) or amphitropic (can replicate in the species of origin and in other species). The mammalian type C viruses of different species appear to differ in their mode of transmission and in disease production.

mammary tumor viruses Viruses in the genus Betaretrovirus. The only well-

Table M1. Mammalian Virus group

Replication-competent viruses

Replication-defective viruses

Feline leukemia virus

Finkel-Biskis-Jinkins murine sarcoma virus

Gibbon ape leukemia virus

Gardner-Arnstein feline sarcoma virus

Guinea pig type C oncovirus

Hardy-Zuckerman feline sarcoma virus

Murine leukemia virus (MLV)

Harvey murine sarcoma virus

Abelson MLV

Kirsten murine sarcoma virus

AKR (endogenous) MLV

Moloney murine sarcoma virus

Friend MLV

Snyder-Theilen feline sarcoma virus

Moloney MLV

Woolly monkey sarcoma virus

Porcine type C oncovirus

characterized member is Mouse mammary tumor virus but related endogenous viruses have been detected in a number of primate and rodent species.

Manawa virus (MWAV) A serotype of Uukuniemi virus in the genus Phlebovirus. Isolated from ticks, Argas abdussalami and Rhipicephalus sp, in western Pakistan. Not reported to cause disease in humans.

Manchester virus A strain of Sapporo virus in the genus 'Sapporo-like viruses'. Isolated from a boy aged 6 months. Complete sequencing of the genome (7266nt) suggested a virus more closely related to animal caliciviruses than to enteric small round structured viruses such as Norwalk, and the 'Sapporo-like viruses' form a distinct genus from the 'Norwalk-like viruses' within the Caliciviridae.

Liu BL et al (1995) Arch Virol 140, 1345

Manitoba virus (MNTBV) An unassigned vertebrate rhabdovirus. Isolated from the mosquito, Culex tarsalis, in Manitoba, Canada. Asymptomatic in mice.

Artsob H et al (1991) Can J Microbiol 37, 329

mannose-binding protein One of a group of proteins (collectins) that can act as part of the innate immune response to interact with viruses such as HIV, HSV or influenza to activate the classical complement pathway and neutralize virus infectivity.

Malhotra R and Sim RB (1995) Trends Microbiol 3,240

M-antibody capture radioimmunoassay (MACRIA) An assay for IgM antibody developed for use in rubella virus diagnosis.

Mortimer PP et al (1981) J Hyg, Camb 86, 139

Manzanilla virus (MANV) A species in the genus Bunyavirus, belonging to the Simbu serogroup. Isolated from the howler monkey, Alouatta siniculus insu-laris, in Trinidad. Not associated with disease in humans.

Mapputta virus (MAPV) An unassigned virus in the family Bunyaviridae.

Serologically related to Gan Gan, Maprik and Trubanaman viruses. Isolated from Anopheles meraukensis in Queensland, Australia. Antibodies present in humans, cattle, horses, pigs, kangaroos and rats. Not reported to cause disease in humans.

Maprik virus (MPKV) An unassigned virus in the family Bunyaviridae. Serologically related to Gan Gan, Mapputta and Trubanaman viruses. Isolated from mosquitoes in the Sepik District of New Guinea. Not reported to cause disease in humans.

map turtle virus Synonym for chelonid her-pesvirus 3.

Mapuera virus (MPRV) A species in the genus Rubulavirus. Isolated from the salivary glands of a fruit bat, Sturnira lilium, captured in the tropical rainforest of Brazil in 1979.

Henderson GW et al (1995) J Gen Virol 76, 2509

Maraba virus (MARAV) A species in the genus Vesiculovirus. Isolated from the sandfly, Lutzomyia sp.

Travassos da Rosa APA et al (1984) Am J Trop Med Hyg 33, 999

Marajo virus An unclassified virus isolated from Culicine mosquitoes in the Amazon region of Brazil. Not known to cause disease in humans.

marble bone disease virus Synonym for osteopetrosis virus.

marble spleen disease of pheasants A disease of pen-raised ring-necked pheasants which occurs in Europe and N America, caused by pheasant adenovirus, an unas-signed virus in the family Adenoviridae. Young adult birds die after an inapparent or short illness due to pulmonary edema. The spleen is enlarged with extensive necrosis and amyloidosis. The main route of infection appears to be fecal-oral. A virus with the morphology of an adenovirus can be seen in the diseased tissue and extracted, but has not been replicated in cell culture. Related antigenically to turkey adenovirus strains TA-1 and TA-2, which cause turkey hem-orrhagic enteritis.

Iltis JP and Daniels SB (1977) Infect Immun 16, 701

Kunze LS et al (1996) Avian Dis 40, 306

marble spleen disease virus Synonym for pheasant adenovirus.

Marboran Trade name for methisazone.

Marburger Affenkrankheit virus Synonym for Marburg virus.

'Marburg-like viruses' One of two genera in the family Filoviridae. The type and only species in the genus is Marburg virus.

Marburg virus (MBGV) The type species of the genus 'Marburg-like viruses'. Causes a severe and often fatal disease in humans. Onset sudden with fever, head and limb pains, bradycardia, diarrhea, vomiting and confused aggressive mental state. Cardiac and renal failure with hemorrhages develop. First reported in 1967 when 31 cases, 7 fatal, occurred in Germany and the former Yugoslavia, all traced to contact with tissues from a batch of African green monkeys, Cercopithecus aethiops, trapped in Uganda. Five secondary cases occurred in hospital workers due to contact with blood from patients, and one case in which the virus was sexually transmitted 83 days after the initial illness. The virus appears to persist in the body for 2-9 months. A second outbreak occurred in 1975 involving one primary case, a man who hitch-hiked through Zimbabwe, and two women who nursed him. Two further cases occurred in 1980 in western Kenya; the index case died and the physician, who was secondarily infected, survived. Then in 1987 another fatal case occurred in western Kenya. Both the 1980 and 1987 cases had visited caves on Mount Elgon 10-12 days before their fatal illness, but intensive ecological studies in the region have failed to identify the virus reservoir. In 1998 fatal cases of Marburg virus infection began to occur in persons who had visited an illegal goldmine in Durba, in the Democratic Republic of the Congo. Over 100 cases were described. Viruses isolated from cases in Durba show wide sequence variation, at least as great as all other Marburg viruses isolated since 1967, suggesting that genetic variants of Marburg virus had been introduced at least seven times into the population in the Durba area. Although the mine is clearly linked to the source of the infection, no reservoir species has so far been identified. Marburg virus causes a uniformly fatal infection in guinea pigs and monkeys, and can be propagated in a variety of cell cultures such as Vero, BHK2l and HeLa. Diagnosis is by antigen capture ELISA or polymerase chain reaction of acute sera, IgM or IgG ELISA of paired (acute and convalescent) sera, or by inoculation of Vero cells which develop eosinophilic inclusions and antigen demonstrable by immunofluorescence. Virus is ether-sensitive and inactivated in 30 min at 56°C. It has an outer envelope and is formed by budding through the cell membrane. There are two structural forms: filamentous and circular. Both have an overall diameter of 70-100nm and contain an internal helix 40nm in diameter. Some filaments may be several microns long; but the unit length associated with peak infectivity is 790nm. The virus has a negative-strand RNA genome, 19.1kb in length, encoding seven proteins, in the order 3'-NP, VP35, VP40, GP, VP30, VP24 and L-5'.

Synonyms: green monkey virus; Marburger Affenkrankheit virus; vervet monkey disease virus.

Feldmann H et al (1998) In Virology, vol. 1 of Topley & Wilson's Microbiology and Microbial Infections, Ninth edition, edited by BWJ Mahy and L Collier. London: Arnold, p. 651 Becker S et al (1996) Virology 225, 145 Peters CJ et al (1996) In Fields' Virology, Third edition, edited by BN Fields et al. Philadelphia: Lippincott-Raven, p. 1161

Table M2. Strains of Marburg virus

Marburg Ravn (Kenya 1987) Marburg Musoke (Kenya 1980) Marburg Ozolin (Zimbabwe 1975) Marburg Popp (West Germany 1967) Marburg Ratayczak (West Germany 1967) Marburg Voege (former Yugoslavia 1967)

Marchai bodies Inclusion bodies found in cells infected with Ectromelia virus.

Marco virus (MCOV) An unassigned vertebrate rhabdovirus. Isolated from the lizard, Ameiva ameiva, in Para, Brazil.

Marrakai virus (MARV)

Pathogenic for newborn mice. Not reported to cause disease in humans. Replicates well with CPE in Vero cells at 30°C. Not isolated from arthropods but considered to be arthropod-transmitted as it will replicate in experimentally infected mosquitoes.

Monath TP et al (1979) Arch Virol 60, 1

Marcy virus Obtained from a case of gastroenteritis in an outbreak in New York State, USA. Could be passed in humans causing anorexia, nausea, vomiting and diarrhea. This virus is now lost, and hence can no longer be identified.

mare abortion virus Synonym for Equid herpesvirus 1.

Marek's disease virus type 1 Synonym for Gallid herpesvirus 2.

Marek's disease virus type 2 Synonym for Gallid herpesvirus 3, a species in the genus 'Marek's disease-like viruses' containing non-oncogenic strains.

Marek's disease virus type 3 (MDV3) See

Meleagrid herpesvirus 1.

'Marek's disease-like viruses' A genus in the subfamily Alphaherpesvirinae containing viruses of birds that form a distinct genetic lineage and cross-react antigeni-cally. There are three species: Gallid herpesvirus 2, representing oncogenic strains of Marek's disease virus, Gallid herpesvirus 3, representing non-oncogenic strains of Marek's disease virus, and Meleagrid herpesvirus 1 (turkey her-pesvirus), which has been used as a vaccine against Gallid herpesvirus 2.

Maridi virus Synonym for Ebola virus Sudan.

Marin county virus A serotype of Human astrovirus in the genus Astrovirus. Isolated from a gastroenteritis outbreak in a Californian nursing home, USA. Now classified as human astrovirus 5.

Herrmann JE et al (1987) Lancet 2, 743

Marituba virus (MTBV) A species in the genus Bunyavirus, belonging to the group

C serogroup. Isolated from sentinel Cebus monkey and mouse in Para, Brazil. Also found in Culex sp. Has been associated with a febrile illness in humans. Antibodies are frequent in arboreal opossums of Caluromys sp and Marmosa sp but not so common in forest floor-dwelling rodents and marsupials.

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