Rabies Virus

AVS 332 - diseases

Is it zoonotic and reportable

• yes, zoonotic

• yes, reportable

Classifications?

• classified as an acute, progressive encephalomyelitis

  • neurotrophic virus

  • enveloped RNA virus

caused by what?

• Lyssavirus

  • Rhabdoviridae

• fatal once clinical signs appear

What does it do, cell wise

• replicates in the site of inoculation

• travels via the peripheral nervous system to the spinal cord and then the brain

• travels from the brain to other organs

  • including the salivary glands

• ultimately this virus will be found in every tissue that is innervated

How many and which species are reservoirs for rabies

• 30

• carnivores, bats, reservoirs can also vectors for this disease

• dogs are the most important reservoir globally

• different variants have developed in different species

  • cross - species transmission does occur

Most known transmission

• most often occurs via the saliva into tissues via a bite

  • a less likely mode of transmission is when the salvia comes in contact with fresh wounds or the mucous membranes

Transmission through dogs, cats, and ferrets

• the virus can be shed 10 days prior to the animal showing symptoms

  • longer in wildlife : can be several weeks

• is not blood borne and there is minimal risk of aerosol transmission

incubation period

• variable

  • amount of virus exposed to

  • locations of exposure on the animal

• more nerves in the tissue the more rapid the on set

• dogs : 21 - 80 days

• humans : can be over 8 years

General symptoms

• behavioral changes

• anorexia

• apprehension or nervousness

• irritability

• overly excitable (hyper excitability)

• progressive paralysis

  • no explanation

Phases of Rabies : Prodromal

• 1-3 days

• non specific symptom that intensify rapidly

• acute excitative

Phases of Rabies : paralytic (end stage)

animals die within a few days once there is the onset of paralysis

Furious Form

• aggression is what is observed in the acute neural excitative phase

• animals may lose fear of humans and attack anything that moves

Paralytic Form

• ataxia and paralysis of throat and jaw muscles

• increase salivation

• unable to swallow

• typically do not bite

Treatment

• no treatment

  • quarantine if exposed

• vaccination

• post exposure treatments

  • HRIG : human rabies immunoglobulin