Systematic Veterinary Virology

PUBLIC HEALTH HAZARDS

• Rabies virus causes highly fatal disease in humanbeings. The incubation period is highly variable, ranging from 7 days to several years. It depends on several factors such as dose of inoculum, severity of the wound, length of the neural path from the wound to the brain e.g. wounds on the face have a shorter incubation period than wounds in the leg.
• The illness begins with a non-specific prodrome period, comprising of fever, malaise, anorexia, sore throat, myalgia and headache. The patient nay exhibit irritability and abnormal sensations around the wound. The prodrome is followed by one of two basic clinical patterns: the more common "furious" form characterized by hyperexcitability, spasms and hydrophobia; or "dumb" rabies featuring an ascending paralysis. Survival tends to be longer for patients with "dumb" rabies than those with "furious" rabies.
• Complications involving the Cardiovacular System, CNS, and the respiratory systems eventually develop and contribute to death. Cardiac dysrhythmias of all types occur and respiratory disturbances occur in all cases. Raised intracranial pressure contributes to the decreased level of consciousness and to focal convulsions. Other CNS complications include disturbances of thermoregulation, diabetes insipidus, autonomic dysfunction and convulsions.
• Once rabies is established, it is always fatal (except in one case in US).