Rabies is a viral disease that causes an acute encephalitis. The rabies virus is classed as a RNA rhabdovirus (specifically a lyssavirus) and has a bullet-shaped capsid. The vast majority of cases are caused by dog bites but it may also be transmitted by bat, raccoon and skunk bites. Following a bite the virus travels up the nerve axons towards the central nervous system in a retrograde fashion.

Epidemiology:

Rabies is estimated to still kill around 25,000-50,000 people across the world each year. The vast majority of the disease burden falls on people in poor rural areas of Africa and Asia. Children are particularly at risk.

Features

• prodrome: headache, fever, agitation
• hydrophobia: water-provoking muscle spasms
• hypersalivation
• Negri bodies: cytoplasmic inclusion bodies found in infected neurons

Management

There is now considered to be 'no risk' of developing rabies following an animal bite in the UK and the majority of developed countries. Following an animal bite in at-risk countries:

• the wound should be washed
• if an individual is already immunised then 2 further doses of vaccine should be given
• if not previously immunised then human rabies immunoglobulin (HRIG) should be given along with a full course of vaccination. If possible, the dose should be administered locally around the wound

If untreated the disease is nearly always fatal.