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RABIES Properties: @ Rabies belongs to Rhabdovirus family @ It is the only human Rhabdovirus virus @ It is bullet-shaped , enveloped, helical, single stranded, linear RNA. Symptoms: @ Incubation period is 10 days to 1 year. @ Fever, malaise, nausea, headache.
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RABIES Properties: @ Rabies belongs to Rhabdovirus family @ It is the only human Rhabdovirus virus @ It is bullet-shaped, enveloped, helical, single stranded, linear RNA.
Symptoms: • @ Incubation period is 10 days to 1 year. • @ Fever, malaise, nausea, headache. • @ Difficulty in sleeping, night mares. • @ Hyperexcitability, muscle spasms • @ Hydrophobia, aerophobia, anxiety • @ Aggression, coma, death.
Classification of Rabies: • @ Furious rabies, characterized by: • * Hyperexcitability • * Muscle spasms • * Hydrophobia • @ Dumb rabies, presents with: • * paralysis only.
Pathogenesis of Rabies: @ Virus in saliva, enters at the site of a bite, or licking cut skin @ Virus replicates at the site of the bite. @ Virus enters peripheral nerves, then the spinal cord, and then the brain. @ Many viral replication occurs in brain @ Virus goes back to salivary glands, heart, lung, liver, skin, retina, cornea.
Laboratory Diagnosis of Rabies In Man @ Specimens: Saliva, CSF, Urine @ Immunofluorescence of cornea smears and skin biopsy of neck or face @ Isolation by inoculating saliva in mice. @ Detection of antibodies by serology @ RNA detection by PCR in blood
Lab. Diagnosis of Rabies In Animals • @ Cytology of brain tissue for Negri • inclusion bodies in nerve cells. • @ Immunofluorescence to detect rabies • antigens in the brain • @ Isolation by inoculating mice. • @ Electron microscopy to detect the • bullet-shaped virus.
Rabies in Animals: • @ Rabies is endemic all over the world • except Australia and Antarctica. • @ Virus infects all warm-blooded animals, • bats, and birds. • @ Urban rabies is transmitted by dogs. • @ Head and neck bites are more serious
Vaccination: @ Vaccine consists of an inactivated virus grown in human embryo lung cells @ It is given as a course of 6 I.M. injection on days 0, 3, 7, 14, 28 and 90 @ Patients with deep or multiple bites should also be injected by rabies immunoglobulins @ Dogs are vaccinated by another inactivated vaccine
Creutzfeldt-Jakob Disease (CJD) • Symptoms: • @ Progressive dementia, ataxia • @ Jerky movements, Difficulty in speech • Aetiology: • @ CJD is known as mad-cow disease • @ Caused by prions virus PrP 27-30 • Creutzfeldt Photo
Prions • @ They are viruses composed of protein • only, without nucleic acid. • @ Resistant to UV light, heat, nucleases, • and formaldehyde • @ Inactivated by hypochlorite, Na OH, • and autoclaving. • @ Composed of a single glycoprotein.
Transmission of CJD: • @ CJD involves the CNS only • @ With long IP (20 years). It is fatal • @Transmission via: corneal grafts, growth • hormone (given to dwarf children), • FSH (given to infertile women). • @ Surgeons & lab. staff are at risk. • @ Transmission from Mad Cow not certain
Lab. Diagnosis • @ Spongiform pathology of the brain • detected by MRI. • @ Detection of PrP 27-30 prion virus at • postmortem and in blood by PCR • @ May be 10-15% hereditary.