Genus Lyssavirus

Type Species	Rabies virus	(RABV)

Distinguishing Features

Lyssaviruses such as rabies virus have 5 major polypeptides, designated L (Mr 190 10³), G (Mr 65-80 10³), N (Mr 58-62 10³), P (Mr 35-40 10³) and M (Mr 22-25 10³). The G protein of rabies virus may be glycosylated at only one or two of the available 3 sites for attachment of N-linked glycans. N and P are phosphoproteins. Phosphorylation of N may involve a host protein kinase; phosphorylation of P probably involves a viral protein kinase (L). The 11.9  kb rabies virus genome includes about 60  nts 3-end sequence that precedes N, about 70  nts untranslated region that follows L and intergenic di- or pentanucleotides, or a 423  nts spacer (between G and L of the PV rabies virus strain). The lyssaviruses that have been analyzed have intergenic regions that are similar to those identified in vesiculoviruses. Rabies virus characteristically induces the formation of Negri bodies in infected neurons.

Biological Properties

Rabies is the oldest known disease caused by a rhabdovirus; it is among the most lethal of all infectious diseases. Rabies is enzootic in all regions of the world except Antarctica. Several island countries (United Kingdom, Ireland, Japan) have remained rabies-free once infected animals were eliminated and strict quarantine and importation regulations were established. Natural animal reservoirs of rabies include many bat species and the skunk, mongoose, raccoon, fox, wolf, jackal, dog, etc. These animals transmit the disease to other species including livestock, domestic animals and wild-life. Transmission from dogs to humans is a major problem in some regions. Transmission usually involves infectious saliva, although other (artificial) forms of transmission have occurred (cornea transplants).

Rabies virus is neurotropic. It multiplies in neurons and myotubes of vertebrates as well as other tissues (e.g., salivary gland). The growth cycle is slow both in vivo and in vitro. Rabies virus infection does not inhibit cellular macromolecular synthesis.

List of Species Demarcation Criteria in the Genus

At present, broadly cross-reacting antigenic sites on the N protein, as recognized by immunofluorescence and complement fixation, determine placement within the genus. More specific antigenic sites on the G protein, as recognized in neutralization tests, determine the placement of a virus isolate as rabies or rabies-related. Cross-neutralization by rabies virus antisera may be moderate (European bat lyssavirus 1, EBLV-1; European bat lyssavirus 2, EBLV-2; Duvenhage virus, DUVV), to very low (Lagos bat virus, LBV; Mokola virus, MOKV). These observations, together with the use of monoclonal antibodies, supported the subdivision of the genus into 4 serotypes (1, Rabies virus, RABV; 2, Lagos bat virus, LBV; 3, MOKV; 4, DUVV) and 2 biotypes of European bat lyssaviruses (EBLV-1; EBLV-2). Genetic characterization at several genomic regions (N, P, and G) supports the subdivision of the genus into 7 genotypes (1, RABV; 2, LBV; 3, MOKV; 4, DUVV; 5, EBLV-1; 6, EBLV-2; 7, Australian bat lyssavirus, ABLV) in agreement with antigenic data. N protein amino acid sequence identities range from 78.% (MOKV and EBLV-2) to 93% (DUVV and EBLV-1). The tentative assignment of Rochambeau virus (RBUV) to the genus remains to be confirmed. Kotonkon virus and Obodhiang virus were formerly assigned to the genus but are now listed as unassigned viruses as serological and molecular data links them to viruses in the genus Ephemerovirus.

List of Species in the Genus

Official virus species names are in italics. Tentative virus species names, alternative names ( ), strains or serotypes are not italicized. Virus names, genome sequence accession numbers [ ], and assigned abbreviations ( ) are:

Species in the Genus

Australian bat lyssavirus	[AF006497]	(ABLV)
Duvenhage virus	[U89483, U22848, AF049115, AF049120]	(DUVV)
European bat lyssavirus 1	[U22845, U22844, AF049113, AF049117]	(EBLV-1)
European bat lyssavirus 2	[U22846, U22847, AF049121]	(EBLV-2)
Lagos bat virus	[U22842, AF049114, AF049119]	(LBV)
Mokola virus	[D00491, D00492, D13767, D13766, S59447, S59448, U22843, U17064]	(MOKV)
Rabies virus	[D10499, D10482, D42112, J02293, L04522-3, L20672, L40426, M13215]	(RABV)

Tentative Species in the Genus

Rochambeau virus	(RBUV)