Orthobunyavirus

Family: Peribunyaviridae; Genus: Orthobunyavirus: Orthobunyavirions are spherical or pleomorphic and have a diameter of 80-120 nm. The enveloped surface (about 5 nm thick) has approximately 18 nm long protrusions of glycoprotein heterodimers (Gn and Gc), of which there are an estimated 650 copies per virion. The surface is a densely packed lattice of glycoprotein Gn-Gc spikes organized in a tripod-like arrangement. Structural analyses have shown that the variable N-terminal half of the Gc glycoprotein consists of two domains: a 27 kDa α-helical head domain and a stalk divided into two identically folded 19 kDa tandem β-sandwiches. The protruding spike is also the main target of the neutralizing antibody reaction.

Nucleic acid: Orthobunyaviruses have the three-part, negative-sense genome organization typical of peribunyaviruses. The terminal nucleotides of each segment (S, M and L) occur in a canonical, conserved sequence (in the coding direction) 5′-AGTAGTGT...ACACTACT-3′. As with other peribunyaviruses, genomic vRNAs are neither polyadenylated nor modified at the 5′-end. Viral mRNAs are not polyadenylated and are truncated compared to vRNA (Abraham and Pattnaik 1983, Eshita et al., 1985). mRNAs possess a 5′-methylated cap that is derived from host mRNA by cap snatching and is mediated by the endonuclease function of the L protein.

Proteins: Like other peribunyaviruses, all orthobunyaviruses contain four structural proteins: Gn, Gc, nucleocapsid (N) and RNA-dependent RNA polymerase/endonuclease protein (L) (Figure 1 Peribunyaviridae, Figure 2 Peribunyaviridae; Table 2 Peribunyaviridae). Non-structural proteins (NSs and NSm) are encoded in the S and M segments in some orthobunyaviruses.

Lipids:The lipids of orthobunyaviruses are derived from the host membranes in which the viruses mature and include phospholipids, sterols, fatty acids and glycolipids. Virions contain 20-30 % lipids.

Carbohydrates: Orthobunyavirions may contain asparagine-linked mannose sugars on the Gn and Gc proteins when grown in vertebrate cells. Carbohydrates make up 7 % of the virion weight.

Genome organization and replication: The S segment encodes N and can encode the non-structural protein NSs in an overlapping ORF downstream (Fuller et al., 1983) or upstream of the N protein initiation codon. However, not all orthobunyaviruses encode NSs. The M segment encodes the Gn and Gc proteins, which are co-translationally cleaved by the host signalase and the signal peptide peptidase. Orthobunyaviruses also encode an NSm protein between the Gn and Gc coding regions (Figure 1 Orthobunyavirus). The L segment encodes the L protein.

Biology: The genus Orthobunyavirus is the largest and most diverse of the family with 138 species. Its members are found worldwide in tropical, temperate and arctic ecological niches. Although a variety of vertebrate and arthropod hosts have been described for viruses in this genus, each virus has a limited arthropod and host range, which in turn limits its geographic distribution. However, some viruses have common hosts and overlapping ranges. Orthobunyaviruses have been isolated from many different vertebrate hosts, including squirrels (La Crosse virus), bats (Mojuí dos Campos virus), rabbits (Snowshoe hare virus), ungulates (Akabane virus), sloths (Oropouche virus) and birds (Mermet virus). Most orthobunyaviruses are transmitted by mosquitoes. However, mosquitoes, bed bugs and wingless bat flies are also known vectors. Some strains are known to be maintained by transovarial transmission in the arthropod host. Orthobunyaviruses are associated with a wide range of human diseases, including encephalitides (e.g. La Crosse virus), febrile illnesses (e.g. Bunyamwera virus) and viral hemorrhagic fevers (e.g. Ngari virus, Garissa variant). Negative effects on animal health include fetal abnormalities and abortions in livestock (e.g. Cache Valley and Schmallenberg viruses). Co-infection with more than one orthobunyavirus can lead to recombination of genome segments both in the laboratory and in nature. Mosquitoes are reservoirs for the recombination of genome segments between heterotypic orthobunyaviruses with common serologic characteristics. In addition, recombination of orthobunyavirus segments has been associated with human disease outbreaks

Antigenicity: The Gn and Gc proteins are responsible for eliciting hemagglutination-inhibiting and neutralizing antibodies. Complement-fixing antibodies are triggered by the nucleocapsid protein. Orthobunyaviruses can be classified into at least 18 serogroups on the basis of haemagglutination inhibition, neutralization and complement fixation tests or remain unclassified (Calisher 1996).

Species within the genus Orthobunyavirus can be defined by:

• Less than 96 % identity in the complete amino acid sequence of the L-protein
• The species Orthobunyavirus acaraense, Orthobunyavirus cuchillaense, Orthobunyavirus bakauense, Orthobunyavirus batamaense, Orthobunyavirus bertiogaense, Orthobunyavirus minatitlanense, Orthobunyavirus mpokoense,Orthobunyavirus olifantsvleiense and Orthobunyavirus turlockense were originally defined according to earlier serological delimitation criteria and not evaluated on the basis of genomic speciation criteria.

Orthobunyaviruses have a broad geographic distribution and a wide host range, although individual viruses may be restricted to a small number of host species. Viruses of this genus form a monophyletic clade when comparing the amino acid sequences of the L protein and encode an NSm and often an NSs protein. Segment rearrangement is well described in related strains and has been associated with the occurrence of disease.

Genus Orthobunyavirus

Species Name

Orthobunyavirus abrasense Abras virus

Orthobunyavirus acaraense Acará virus

Orthobunyavirus acaraense Benevides virus

Orthobunyavirus achiotei Achiote virus

Orthobunyavirus achiotei Trivittatus virus

Orthobunyavirus ainoense Aino virus

Orthobunyavirus akabaneense Akabane virus

Orthobunyavirus akabaneense Tinaroo virus

Orthobunyavirus anadyrense Anadyr virus

Orthobunyavirus ananindeuaense Ananindeua virus

Orthobunyavirus angeloense San Angelo virus

Orthobunyavirus anhembiense Anhembi virus

Orthobunyavirus apeuense Apeú virus

Orthobunyavirus baakalense Baakal virus

Orthobunyavirus bakauense Bakau virus

Orthobunyavirus bakauense Tanjong Rabok virus

Orthobunyavirus balagoduense Balagodu virus

Orthobunyavirus barritaense Barrita virus

Orthobunyavirus bataiense Batai virus

Orthobunyavirus batamaense Batama virus

Orthobunyavirus belemense Belém virus

Orthobunyavirus bellavistaense Antequera virus

Orthobunyavirus bellavistaense Barranqueras virus

Orthobunyavirus bellavistaense Bellavista virus

Orthobunyavirus bellavistaense Resistencia virus

Orthobunyavirus belmontense Belmont virus

Orthobunyavirus benficaense Benfica virus

Orthobunyavirus bertiogaense Bertioga virus

Orthobunyavirus bertiogaense Cananéia virus

Orthobunyavirus biraoense Birao virus

Orthobunyavirus bobayaense Bobaya virus

Orthobunyavirus boraceiaense Boracéia virus

Orthobunyavirus botambiense Botambi virus

Orthobunyavirus bozoense Bozo virus

Orthobunyavirus brazoriaense brazoran virus

Orthobunyavirus bruconhaense Bruconha virus

Orthobunyavirus buffaloense Buffalo Creek virus

Orthobunyavirus buffaloense Murrumbidgee virus

Orthobunyavirus buffaloense Trubanaman virus

Orthobunyavirus bunyamweraense Bunyamwera virus

Orthobunyavirus bunyamweraense Germiston virus

Orthobunyavirus bunyamweraense Mboké virus

Orthobunyavirus bunyamweraense Ngari virus

Orthobunyavirus bunyamweraense Stanfield virus

Orthobunyavirus bunyamweraense Xingu virus

Orthobunyavirus bushbushense Bushbush virus

Orthobunyavirus bushbushense Moriche virus

Orthobunyavirus buttonwillowense Buttonwillow virus

Orthobunyavirus bwambaense Bwamba virus

Orthobunyavirus bwambaense Pongola virus

Orthobunyavirus cacheense Cache Valley virus

Orthobunyavirus cacheense Cholul virus

Orthobunyavirus cacheense Playas virus

Orthobunyavirus cacheense Tlacotalpan virus

Orthobunyavirus capimense Capim virus

Orthobunyavirus caraparuense Caraparú virus

Orthobunyavirus caraparuense El Huayo virus

Orthobunyavirus caraparuense Itaquí virus

Orthobunyavirus caraparuense Itaya virus

Orthobunyavirus catqueense Cát Quế virus

Orthobunyavirus catqueense Oya virus

Orthobunyavirus catuense Catú virus

Orthobunyavirus catuense Moju virus

Orthobunyavirus cuchillaense Anopheles B virus

Orthobunyavirus ebiense Ebinur Lake virus

Orthobunyavirus encephalitidis California encephalitis virus

Orthobunyavirus encephalitidis Morro Bay virus

Orthobunyavirus enseadaense Enseada virus

Orthobunyavirus faceyense Facey's paddock virus

Orthobunyavirus gamboaense Alajuela virus

Orthobunyavirus gamboaense Brus Laguna virus

Orthobunyavirus gamboaense Calchaquí virus

Orthobunyavirus gamboaense Gamboa virus

Orthobunyavirus gamboaense Soberanía virus

Orthobunyavirus ganganense Gan Gan virus

Orthobunyavirus ganganense Salt Ash virus

Orthobunyavirus guajaraense Guajará virus

Orthobunyavirus guamaense Bimiti virus

Orthobunyavirus guamaense Guamá virus

Orthobunyavirus guaratubaense Guaratuba virus

Orthobunyavirus guaratubaense Itimirim virus

Orthobunyavirus guaroaense Guaroa virus

Orthobunyavirus gumbolimboense Gumbo limbo virus

Orthobunyavirus heptayabaense Yaba-7 virus

Orthobunyavirus horizonteense Anopheles A virus

Orthobunyavirus horizonteense Arumateua virus

Orthobunyavirus horizonteense Caraipé virus

Orthobunyavirus horizonteense Trombetas virus

Orthobunyavirus horizonteense Tucuruí virus

Orthobunyavirus iacoense laco virus

Orthobunyavirus ileshaense Ilesha virus

Orthobunyavirus indianense I612045 virus

Orthobunyavirus infirmati Infirmatus virus Tampa 08

Orthobunyavirus ingwavumaense Ingwavuma virus

Orthobunyavirus insulae kairi virus

Orthobunyavirus jamestownense Inkoo virus

Orthobunyavirus jamestownense Jamestown Canyon virus

Orthobunyavirus jamestownense Jerry Slough virus

Orthobunyavirus jamestownense South River virus

Orthobunyavirus jatobalense Jatobal virus

Orthobunyavirus juandiazense Juan Díaz virus

Orthobunyavirus kaengkhoiense Kaeng Khoi virus

Orthobunyavirus kernense Lokern virus

Orthobunyavirus kernense Main Drain virus

Orthobunyavirus kernense Santa Rosa virus

Orthobunyavirus ketapangense Ketapang virus

Orthobunyavirus keystoneense Keystone virus

Orthobunyavirus khatangaense Khatanga virus

Orthobunyavirus khatangaense snowshoe hare virus

Orthobunyavirus koongoli koongol virus

Orthobunyavirus koongoli wongal virus

Orthobunyavirus kowanyamaense Kowanyama virus

Orthobunyavirus lacrosseense La Crosse virus

Orthobunyavirus lasmaloyasense Las Maloyas virus

Orthobunyavirus leanyerense Leanyer virus

Orthobunyavirus ledniceense Lednice virus

Orthobunyavirus lichuanense Lichuan virus

Orthobunyavirus lukuniense Lukuni virus

Orthobunyavirus lumboense Lumbo virus

Orthobunyavirus macauaense Macauã virus

Orthobunyavirus madridense Madrid virus

Orthobunyavirus madridense Vinces virus

Orthobunyavirus maguariense Maguari virus

Orthobunyavirus mahoganyense Mahogany Hammock virus

Orthobunyavirus manzanillaense Inini virus

Orthobunyavirus manzanillaense Manzanilla virus

Orthobunyavirus maprikense Maprik virus

Orthobunyavirus maritubaense Marituba virus

Orthobunyavirus maritubaense Zungarococha virus

Orthobunyavirus matruhense Matruh virus

Orthobunyavirus melajoense Melao virus

Orthobunyavirus mermetense Mermet virus

Orthobunyavirus minatitlanense Minatitlán virus

Orthobunyavirus minatitlanense Palestina virus

Orthobunyavirus mirimense Mirim virus

Orthobunyavirus mitchellense Mapputta virus

Orthobunyavirus mpokoense M'Poko virus

Orthobunyavirus mpokoense Yaba-1 virus

Orthobunyavirus navioense Serra do Navio virus

Orthobunyavirus nepuyoi Nepuyo virus

Orthobunyavirus nesszionaense Ness Ziona virus

Orthobunyavirus nolaense Nola virus

Orthobunyavirus northwayense Northway virus

Orthobunyavirus nyandoense Eretmapodites virus

Orthobunyavirus nyandoense Mojuí dos Campos virus

Orthobunyavirus nyandoense Nyando virus

Orthobunyavirus okolaense Okola virus

Orthobunyavirus olifantsvleiense Bobia virus

Orthobunyavirus olifantsvleiense Dabakala virus

Orthobunyavirus olifantsvleiense Olifantsvlei virus

Orthobunyavirus olifantsvleiense Oubi virus

Orthobunyavirus oribocaense Murutucú virus

Orthobunyavirus oribocaense Oriboca virus

Orthobunyavirus oribocaense Restan virus

Orthobunyavirus oropoucheense Iquitos virus

Orthobunyavirus oropoucheense Madre de Dios virus

Orthobunyavirus oropoucheense Oropouche virus

Orthobunyavirus oropoucheense Perdões virus

Orthobunyavirus oropoucheense Pintupo virus

Orthobunyavirus oyoense Oyo virus

Orthobunyavirus pacoraense Pacora virus

Orthobunyavirus parkeri Parker's Farm virus

Orthobunyavirus patoisense Babahoya virus

Orthobunyavirus patoisense Pahayokee virus

Orthobunyavirus patoisense Patois virus

Orthobunyavirus peachesterense Peaton virus

Orthobunyavirus porteiraense Cachoeira Porteira virus BeAr328208

Orthobunyavirus potosiense Potosi virus

Orthobunyavirus saboense Sabo virus

Orthobunyavirus sangoense Sango virus

Orthobunyavirus sanjuanense Pueble Viejo virus

Orthobunyavirus sanjuanense San Juan virus

Orthobunyavirus schmallenbergense Douglas virus

Orthobunyavirus schmallenbergense Sathuperi virus

Orthobunyavirus schmallenbergense Schmallenberg virus

Orthobunyavirus schmallenbergense Shamonda virus

Orthobunyavirus sedlecense Sedlec virus

Orthobunyavirus shermanense Fort Sherman virus

Orthobunyavirus shermanense Laguna Larga virus

Orthobunyavirus shokweense Shokwe virus

Orthobunyavirus shuniense Shuni virus

Orthobunyavirus simbuense Para virus

Orthobunyavirus simbuense Simbu virus

Orthobunyavirus sororocaense Sororoca virus

Orthobunyavirus squalofluvii Shark River virus

Orthobunyavirus sussexense Little Sussex virus

Orthobunyavirus tacaiumaense CoAr 1071 virus

Orthobunyavirus tacaiumaense CoAr 3627 virus

Orthobunyavirus tacaiumaense Tacaiuma virus

Orthobunyavirus tacaiumaense Virgin River virus

Orthobunyavirus tahynaense Ťahyňa virus

Orthobunyavirus taiense Tai orthobunyavirus

Orthobunyavirus tangaense Tanga virus

Orthobunyavirus taniyamense Taniyama virus

Orthobunyavirus tataguineense Tataguine virus

Orthobunyavirus telokense Telok Forest virus

Orthobunyavirus tensawense Tensaw virus

Orthobunyavirus termeilense Termeil virus

Orthobunyavirus teteense Bahig virus

Orthobunyavirus teteense Tete virus

Orthobunyavirus teteense Tsuruse virus

Orthobunyavirus teteense Weldona virus

Orthobunyavirus thimiriense Thimiri virus

Orthobunyavirus timboteuaense Timboteua virus

Orthobunyavirus trinitiense Triniti virus

Orthobunyavirus turlockense Turlock virus

Orthobunyavirus umbreense Umbre virus

Orthobunyavirus utingaense Utinga virus

Orthobunyavirus witwatersrandense Witwatersrand virus

Orthobunyavirus wolkbergense Wolkberg virus

Orthobunyavirus wyeomyiae Rio Pracupi virus

Orthobunyavirus wyeomyiae Taiassui virus

Orthobunyavirus wyeomyiae Tucunduba virus

Orthobunyavirus wyeomyiae Wyeomyia virus

Orthobunyavirus yacaabaense Yacaaba virus