Rabies is caused by rabies virus, and humans can be infected by being bitten by homoiotherms infected by rabies, such as dogs, cats, wolves, and foxes.


Causes

Rabies virus is single-stranded RNA virus, a member of rhabdovirus, 75 × 180 nm in size, with capsule on the outer layer, with nucleoprotein in the core, sensitive to lipid solvents. The virus is mainly in the saliva and brain tissue of infected animals.


Signs and Symptoms

Human rabies is mostly infected by bites or scratches of animals with rabies. The incubation period is as short as 10 days, as long as 2 years or longer, generally 31 - 60 days. 15% of rabies occur 3 months after being bitten.

The prodromal period is about 1 - 4 days, and the manifestations are moderate fever, malaise, loss of appetite, headache, and nausea. Subsequently, there are nervous symptoms such as elevated irritability, chest tightness, chest pain, aerophobia, hypermyotonia, and spasticity of facial muscles. If the sympathetic nervous system is involved, there are sweating, hydrostomia, mania, anxiety, and spastic painful muscle contractions. Muscle spasms in the throat when swallowing cause fear of drinking water, which is known as hydrophobia. Ascending paralysis can occur at different stages of the disease, especially in rabies transmitted from bats. Patients eventually die of respiratory and circulatory failure.


Diagnosis

If there are a history of exposures to suspect animals, clinical manifestations, and rabies virus isolated from saliva and cerebrospinal fluid, the disease can be diagnosed.


Treatment

Once humans are bitten or scratched, treatment should be initiated immediately.

The bite sites should be rinsed with soap and water, followed by 40% - 70% alcohol or benzyl ammonium chloride. The suture of wounds should be postponed.

Anti-rabies serum 40U/kg or human rabies immunoglobulin 20U/kg should be injected locally.


Post-exposure prophylaxis

Vaccine should be administered immediately after exposures, and there are 5 doses regimen and 2-1-1 doses regimen.

5 doses regimen is 1 dose on the 0th, 3rd, 7th, 14th, 28th day intramuscularly, while 2-1-1 doses regimen is 2 doses on the 0th day followed by 1 dose on the 7th and 21st day intramuscularly.

If the bites are severe or the wounds are close to the central nervous system, the dose of vaccine can be doubled.