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Rhabdoviruses. 桿狀病毒. I. Classification. Genus Lyssavirus : rabies virus ( 狂犬病毒屬 ) Three rabies-like viruses. II. Structure. Bullet-shaped, single-stranded, negative-sense enveloped RNA virus Single segment The virus genome encodes five proteins. III. Multiplication.
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Rhabdoviruses 桿狀病毒
I. Classification • Genus • Lyssavirus:rabies virus (狂犬病毒屬) • Three rabies-like viruses
II. Structure • Bullet-shaped, single-stranded, negative-sense enveloped RNA virus • Single segment • The virus genome encodes five proteins.
III. Multiplication • Replication in cytoplasm • Parental (-) RNA virus --->+RNA --->progeny-RNA virus.
IV. Clinical manifestation • Cause acute infection of the central nervous system. • Five stages in humans:incubation -->prodrome(前驅期) -->acute neurologic period急性腦炎(神經錯亂)→腦幹中樞功能障礙期(多口水,恐水症)-->coma(昏迷)-->death(死於神經及呼吸衰竭) • Incubation time:5 days to 2 years
V. Pathogenesis • replicate in muscle tissue-->remaining sequestered at or near the entry site during incubation-->entering the peripheral nervous system-->migrating rapidly to numerous organs.
VI. Hosts defenses • Antibody is protective only if present before virus enters the nerves.
VII. Epidemiology • occur in nearly all countries • due to a bite by an infected mammal.
VIII. Diagnosis • Symptom observation and the detection of antibody are too late for clinical purpose. Tests of viral antigen or serological finding are used for suspected animal. • Negri body in infected neurons, eosinophilic cytoplasmic inclusion filled with viral nucleocapsids is a hallmark diagnosis for rabies.
IX. Control • Control is by vaccination of susceptible animal species, particularly dogs and cats. • Vaccination with HDCV for pre-exposure prophylaxis. • Administration of both HRIG (抗狂犬病毒免疫血清) and vaccines around the wound for post-exposure prophylaxis.