Cases of rabies have come up in the past week with children in villages near Serian, Sarawak being hospitalised after animal bites.

Two children have died so far.

Rabies is caused by a virus (genus Lyssavirus), and is derived from the Latin word for “to rage”.

The disease has been recognised for over 4,000 years, though it was only in 1885 that the first vaccine for it was created by French biologist Louis Pasteur.

That vaccine is the predecessor of the highly effective vaccines we have today.

The virus is transmitted through the infected saliva of a host animal, usually through a bite or scratch from an infected animal.

According to the World Health Organization (WHO), dogs are the main source of infection, contributing up to 99% of all rabies transmissions to humans.

Many animals can be host to the rabies virus, although it’s most common in dogs, cats, bats, foxes, jackals and mongooses.

How rabies is transmitted

The virus attacks the central nervous system following a bite. It spreads through the nerve cells, eventually reaching the brain.

In the brain, the virus multiplies rapidly, causing severe inflammation. When this happens, the victim deteriorates rapidly.

It usually takes some time after a bite before symptoms appear – usually four to 12 weeks after infection (though it may be shorter, or longer, in some instances).

However, symptoms may appear quicker if the site of the bite or scratch is on the head and neck, possibly because it takes less time for the virus to reach the brain.

The initial symptoms are nondescript, such as fever, headache, and general weakness or discomfort.

However, as the disease progresses, central nervous system symptoms surface, such as anxiety, agitation, confusion, muscle weakness and hallucinations.

In the later stages, the victim may exhibit hydrophobia (which also happens to be the old name for rabies) – fear of water.

Eventually, death ensues.

Rabies illustration

Infection in humans

In humans, the disease can manifest in two different ways:

• Furious rabies – the victim is hyperactive and excitable and may display erratic behaviour. This is the more common of the two, about 70-80% of cases.

• Paralytic rabies – the victim slowly becomes paralysed and will eventually slip into a coma.

Unfortunately, there is no test to detect the early stages of rabies. It is only after symptoms appear that a blood or tissue test will determine whether you have the disease.

Hence, any suspicion of rabies will be treated with shots of rabies vaccine.

The victim will be given a shot of rabies immunoglobulin. This gives an immediate dose of rabies antibodies to fight the infection. The aim is to prevent the virus from multiplying rapidly.

Then a series of four shots of rabies vaccine is given over two weeks – the first dose is given together with the immunoglobulin, then further shots on the third, seventh and fourteenth days.

Getting these shots the soonest possible after a scratch or bite from an animal suspected of having rabies is the best way to prevent the infection.

For those who have not been exposed to the virus, or are at high risk of exposure (such as in work or travelling), preventive vaccination has a different protocol – there are three doses, with the second one given a week after the first dose, and the third at 21 or 28 days after the first dose.

Because a vaccine is available, rabies is a preventable disease. Simple measures you can take for prevention include vaccinating your pets, keeping your pets from roaming too far outside, reporting stray animals and avoiding contact with wild animals.