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Lyssavirus (rabies)

ISSN 2398-2950

Synonym(s): Rabies virus




  • Family: Rhabdoviridae.
  • Genus: Lyssavirus.
  • RNA virus.


  • Gk: rhabdos- rod; refers to the shape of the virus. Often described as bullet-shaped; lyssa- rage, fury.


  • Widely distributed throughout the world except in some European countries (including United Kingdom, Italy, France and Switzerland), Australia, New Zealand, Japan, Antarctica and some Caribbean countries.
  • Particularly prevalent in India which accounts for a third of the global total of human deaths due to rabies.


  • Causes rabies Rabies.
  • All mammals susceptible. Birds also susceptible but less so than mammals.

Active Forms

Active Form 1


  • Cylindrical shape with 1 rounded and 1 planar end. Knob-shaped projections are regularly arranged over the surface of the virion.


  • Inactivated by 1% formalin, 3% cresol and 0.1% beta-propiolactone.
  • Inactivated by organic solvents, detergents.


  • Rabies virus will grow in many cell lines. Optimal growth in cell culture at 37°C in an atmosphere of 0.5% carbon dioxide and 90% humidity.
  • Single-stranded negative-sense RNA genome of about 12,000 nucleotides.
  • Replicates in cytoplasm of host cell, forming typical "Negri bodies", containing viral ribonucleoprotein.
  • Persists in infected brain tissue for 7-10 days at room temperature and for several weeks at 4°C.

Resting Forms

Clinical Effects



  • Important reservoir hosts are foxes, skunks, wolves, raccoons, mongoose, coyotes and bats, depending on region. These animals carry infectious virus in their salivary glands.


  • Following transmission (usually by biting), rabies virus persists in local muscle tissue for hours or days.
  • Initial replication may occur in muscle cells.
  • Virus is taken up by motor nerve endings and spreads to the CNS, where further replication occurs.
  • Virus then spreads to other organs, eg salivary glands, cornea and tonsils.


  • Saliva: bites from infected animals.
  • Unlikely modes of transmission include transplants, sexual transmission.

Pathological effects


Control via animal


  • Strict 6 month period of quarantine of animals when imported into rabies-free countries from countries where rabies is endemic.
  • Elimination of stray dogs and cats and immunization of all mammalian pets with live attenuated virus or inactivated vaccine to control urban rabies in countries where rabies is endemic.
  • The  Rabies (Importation of Dogs, Cats and Other Mammals) Order 1974 prohibits entry of rabies-susceptible animals into Great Britain unless issued with an import licence by the APHA (Animal Plant and Health Agency).
  • The Non-Commercial Movement of Pet Animals Order 2011 states that pet dogs, cat and ferrets are not subject to the requirements of the Rabies (Importation of Dogs, Cats and Other Mammals) Order 1974, providing the following rules are adhered to:
    • The pet cat, dog or ferret has a microchip.
    • The pet cat, dog or ferret has a pet passport.
    • The pet cat, dog or ferret has been vaccinated against rabies and require a blood test if traveling from an unlisted country.
    • Dogs must also have tapeworm treatment.
  • Quarantine up to 4 months at the owner's expense is required if the above rules are not followed.


  • Vaccination of mammalian pets in countries where rabies is endemic.
  • Oral immunization of wildlife in some European countries has been successful.
  • Such vaccination must take place at least 3 months of age, using inactivated and adjuvanted rabies vaccine.
  • Vaccination must be boosted at least annually.
  • Success of vaccination will be checked using a blood test; animals must show a rabies antibody titer ≥ 0.5 IU/ml.


Useful samples

  • Brain tissue.

Specimen storage

  • Store brain material in 50% glycerol.
    Do not fix tissues in formalin.

Laboratory diagnosis

  • Identification of Negri bodies in brain tissue; pathognomonic.
  • Fluorescent antibody technique for viral antigen in the brain.

Further Reading


Refereed papers

Other sources of information