Rabies A82.9

Fatal viral disease (rabies virus) with severe viral enephalomyelitis and related neurological disorders due to transmission of the pathogen with the saliva of the infected animal by biting or contamination of a wound or mucous membrane.

• Rabies virus, genus Lyssaviruses, family Rhabdoviridae.
• A total of seven genotypes:
• Genotype 1: Rabies virus (RABV). This virus is the classic rabies virus.
• Genotype 2: Lagos bat virus = Lagos bat virus (LBV)
• Genotype 3: Mokola virus (MOKV)
• Genotype 4: Duvenhage virus (DUVV)
• Genotypes 5 and 6: European bat lyssavirus = European bat lyssavirus (EBLV 1, 2)
• Genotype 7: Australian bat lyssavirus = Australian bat lyssavirus (ABLV).
• With the exception of genotype 2, rabies cases in humans are described for all other genotypes listed above.
• Transmission through bite wounds and through contact of saliva with existing small skin wounds. Transmission by organ transplantation is possible.

Worldwide distribution. Rabies-free are Australia, parts of the Caribbean, New Zealand, Japan, Oceania, Papua New Guinea.

Main carriers are carnivorous and bloodsucking wild animals, foxes, dogs, cats, skunks, bats, jackals.

40,000-70,000 people die of rabies every year, most of them in Asia (approx. 80%) and in Eastern Europe. Half of the deaths worldwide affect children and young people under 15 years of age. A not inconsiderable number of unreported cases must be expected in addition to those reported.

In Milwaukee, one patient survived after antiviral treatment in 2004.

Incubation period: normally 3-12 weeks (90%); rarely up to 10 years possible.

If transmitted by animal bite, severe skin and/or soft tissue infections may occur.

Pain in the bitten extremity at first. Loss of sensitivity according to the skin dermatomes, then central nervous symptoms (encephalitis, myelitis), such as paralysis, anxiety, confusion, agitation, progressing to delirium, abnormal behaviour, hallucinations and insomnia, paralysis of the throat, pharyngeal spasms, combined with an inability to speak or swallow, hydrophobia. The slightest environmental stimuli, noises, light lead to tantrums, screaming, hitting and biting.

The disease can also progress in the "silent" form, in which some of the symptoms mentioned are missing.

Death 2-10 days after the first symptoms appear.

During the lifetime of the patient: antigen or rabies virus RNA detection in corneal epithelial cells, in neck skin biopsies, in saliva (pharyngeal irrigation water) or in cerebrospinal fluid. Virus detection via cell cultures.

Confirmation of the suspected clinical diagnosis post mortem, for example from samples from the ammonium horn, cerebellum and brain stem. The detection of negri inclusion bodies in sectional preparations of brain tissue can allow an etiological assignment to rabies in cases of death of unclear genesis according to neurological symptoms.

For the detection of vaccine titres, antibodies can be detected with the neutralisation test (RFFIT - rapid focus fluorescent inhibition test).

Magnetic resonance tomography: brightening in the region of the hippocampus and at the caudate nucleus.

• Clean the contaminated wound immediately and thoroughly with soap solution or water and disinfect with alcohol. Flush deep bite wounds with catheters.
• Observation of the animal: if the animal is still alive 10 days after the bite wound, rabies can be excluded, otherwise post-mortem diagnostics of the brain.
• The treatment is carried out symptomatically under intensive care conditions (control of respiration, circulation, CNS symptoms).
• Therapy option: Milwaukee scheme consisting of ribavirin, amantadine, among others.
• Only during the early phase, i.e. in the first few hours, post-exposure vaccination is recommended. Once the virus has reached the brain, vaccination is no longer effective.
• Current recommendation for the indication of post-exposure prophylaxis under http://www.rki.de.
• The measures of post-exposure rabies prophylaxis should be taken if the suspicion of a rabies virus infection cannot be ruled out.
• For grade III exposures, simultaneous administration of rabies immunoglobulin: inject 20-30IE/kgKG half i.m., half into and around the wound) + Rabies vaccine for active immunisation (e.g. 1ml Rabivac® rabies HDC vaccine). The active immunisation is carried out according to the manufacturer's instructions using various schemes. A common scheme is vaccine vaccination on days 0, 3, 7, 14, 28. If applied in time, the protection rate after active immunisation is 100% for peripheral injuries.
• However, an indicated post-exposure prophylaxis should always be carried out, regardless of the time that has elapsed since the injury.

• Pre-exposure prophylaxis with dead vaccine.
• Vaccination of animals (including vaccination bait).

Remember! According to § 6 IfSG there is a duty to report by name the injury of a human being by an animal suffering from, suspected of suffering from or suspected of being infected with rabies as well as the contact of such an animal or animal body.

Notice! According to § 7 IfSG the direct or indirect proof of the Rabies virus is subject to reporting.

Indication for post-exposure rabies vaccination:

• Touching or feeding of animals, licking of the intact skin:no vaccination

• nibbling on uncovered skin; superficial scratches that do not cause bleeding; licking of non-intact skin: active immunization

• Any bite or scratch wounds that penetrate the skin; contamination of mucous membranes with saliva (e.g. splashes): active + passive immunization

1. Bronnert J et al (2007) Organ transplantations and rabies transmission. J Travel Med. 14:177-180.
2. Wyatt J (2007). Rabies-update on a global disease. Pediatric Infect Dis J. 26:351-352
3. Velasco-Villa A et al (2017) The history of rabies in the Western Hemisphere.
   Antiviral Res 146:221-232.