RABIES

Mgr. Kateřina Podveská

PhDr. Lenka Řitičková

Mgr. Silvie Schüllerová, Ph.D.

Basic facts

from Latin rabies, ei. F viral zoonotic disease causes acute encephalitis

(inflammation of the brain) in warm-blooded animals

transmitted by a bite from an infected animal (dogs, foxes, bats, monkeys, skunks, raccoons etc.)

the period between infection and symptoms – incubation period – is normally two to twelve weeks (eventually two years)

in humans the incubation period is usually several months depending on the distance the virus travels to the CNS

Basic facts (2)

the rabies virus travels to the brain (follows the peripheral nerves)

infects CNS brain inflammation

once it reaches the central nervous system and symptoms begin to show, the infection is effectively untreatable

almost invariably fatal disease if post-exposure prophylaxis not administered prior to onset of severe symptoms

Symptoms

early-stage headache and fever, malaise, acute pain violent movements, uncontrolled excitement depression and hydrophobia, periods of mania and lethargy coma

later stages

production of large quantities of saliva and tears coupled with an inability to swallow (throat paralyzation)

respiratory insufficiency – primary cause of death death two to ten days after the first symptoms the disease eliminated substantially due to animal

control and vaccination programs

The rabbies virus

type species of the Lyssavirus genus in the family Rhabdoviridae, order Mononegavirales

helical symmetry with the length of approx. 180 nm

enveloped and single stranded RNA

neurotropic, travels quickly into CNS and further organs

salivary glands recieve high concentration of the virus thus allowing further transmission

Diagnosis

• animals

• PCR (polymerase chain reaction) or viral culturing on brain, skin, saliva or urine samples

• inclusion bodies called Negri bodies (stainable substances/proteins indicating viral multiplication) are 100%

• humans

• differential diagnoses in case of suspected human rabies may initially include any cause of encephalitis, particular infections of viruses such as herpes virus, enterovires or arboviruses

Occurance

• common in all continental regions of Asia, America and Africa

• Greenland and many countries in Europe - rabies in animal population

• Scandinavia, the British Isles, Japan, Australia and New Zealand are rabies free

Transmission

• 7,000 cases in animals reported annually to Centres for Diseas Control and Prevention (CDC)

• most common carries - raccoons, foxes, and dogs

• the most likely to infect people in USA are bats

• due to widespread vaccination programs transmisson from dogs to people is rare

Prevention

• until 1885 all human rabies cases were fatal

• 1885 – Luis Pasteur and Emile Roux invented rabies vaccine

• virus harvested from infected rabbits was subsequently weakened by allowing it to dry for five to ten days

• 1967 - the human diploid cell rabies vaccine was started

• 1970s - new less expensive chicken purified embryo cell vaccine and purified Vero cell rabies vaccine available

Louis Pasteur

• patients being vaccinated against rabies at the Pasteur Institute in Paris, France

• Louis Pasteur’s rabies virus was milder with a shorter incubation period than the wild virus

• a person bitten by a rabid animal would be inoculated with the Pasteur virus and rapidly develop immunity to the wild strain

• The first human patient (Joseph Meister) was successfully treated in 1885

Prognosis

• in unvaccinated humans, rabies is mostly fatal after neurogological symptoms have developed

• rabies kills around 55,000 people per year (mostly Africa and Asia)

• there are only about six known cases of a person surviving symptomatic rabies

…and

domesticated animals are required to be vaccinated in many jurisdictions

September 28 World Rabies Day

Thank you for your attention