Updated 26 September 2014

Rabies worse scourge than Ebola

Now claiming around 74 000 lives a year globally, rabies is the top infection transmitted to humans from animals and has been called "the deadliest disease on earth".

In Africa alone, conservative estimates are that rabies kills 100-200 people a day.

"By comparison, Ebola deaths are only a small fraction," said Dr Sarah Cleveland, a pre-eminent rabies expert from the University of Glasgow, speaking at the recent World Small Animal Veterinary Association (WSAVA) Congress held in Cape Town.

A 'horrific' disease

WSAVA's focus on what Cleveland called a "horrific" viral disease is part of the lead-up to World Rabies Day on 28 September 2014.

The Global Alliance for Rabies Control gives rabies the title of "the deadliest disease on earth": there is a 99.9% fatality rate once symptoms appear.

The virus attacks the brain, and most cases are termed "furious rabies", which typically involves delusions or hallucinations and aggressive, agitated behaviour.

Some cases take the form of "dumb" or paralytic rabies, in which the muscles become progressively paralysed.

Death follows when the person enters a coma, usually as a result of heart or lung failure.

Read: How to identify rabies.

Rabies mainly affects people living in poor rural communities, but anyone is potentially at risk if they have contact with unvaccinated animals.

One such high-profile case that brought the disease to public attention was when canoeist Graham Anderson died: he contracted rabies when a dog rescued from a village in KwaZulu-Natal licked an area of broken skin.

The highest risk areas for rabies in South Africa are impoverished rural areas in KwaZulu-Natal, Eastern Cape, Mpumalanga and Limpopo. Death rate from rabies is around 13 people per year, but this does not include cases that go unreported. Incidence is lower in urban areas and townshiips, and very low in affluent areas where there are high levels of veterinary care.

Nonetheless, a bite from any animal should be considered potentially rabid unless a veterinarian can show that the animal's vaccinations are up-to-date.

The good news as regards rabies is that post-exposure prophylaxis (PEP) i.e. vaccine given in time after a bite or scratch from a rabid animal, stops the virus. PEP must be received before symptoms appear, however.

When man's best friend turns foe

Dogs are by far the most important rabies host: 98% of human rabies cases are the result of dog bites.

In Africa and Asia, where most rabies cases occur, fear of rabies can turn people against their dogs, leading to unnecessary exclusion, cruelty and culling - often of healthy dogs.

There is strong demand for dogs in many African communities; when a dog population is reduced locally, new dogs are brought in from surrounding areas - and these may re-introduce the rabies virus.

Read: Dog bite: what to do

Vaccinating dogs an effective, humane solution

Rabies experts at the WSAVA conference agreed widespread vaccination of dogs to be by far the most effective, humane way of stopping this disease at source.

It is also much more economical, because it reduces the need for PEP, which is very costly. In many parts of Africa, infected people tragically don't reach medical facilities in time, often because they can't raise sufficient funds for the journey, let alone the treatment.

Some cases, said Cleveland, are not recognised as rabies. They are seen as "bewitchment", or, as has happened in Malawi, misdiagnosed as cerebral malaria.

Watch: symptoms of rabies in humans and dogs

Africa: a continent of dog-owners

There is a common misconception that Africa is home to many stray dogs, say rabies researchers. In fact, although most dogs are free-roaming and not kept inside properties, about 90% of them have owners, who usually name their animals.

This greatly facilitates rabies control efforts, as dogs can be traced through their owners, with whom the vaccination programmes are proving popular.

"Kids are particularly good at bringing favourite dogs to be vaccinated," said Cleveland. She pointed out that under-15s (particularly boys) are also the age group most likely to receive dog bites.

Read: Children most likely to contract rabies

Threat to wildlife

Rabies can affect a wide variety of mammals apart from dogs. In Africa, these include many wild mammals such as jackals, bats, mongeese, wild dogs, lions, primates - and even sometimes herbivores like kudu.

As with infection in humans, domestic dogs are the main source of rabies transmission to wild animals; so canine vaccination would protect precious wildlife too.

Dr Cleveland reported that the Serengeti-Mara in East Africa, world-famous for its rich wildlife, is also home to some 6 million people - and their dogs.

When herds of animals migrate in the Serengeti, they come into contact with dogs on the perimeter of the wildlife conservation area, and some get bitten or killed. Wild predators then contract rabies in turn from their prey - infected herd animals.

Whole wild dog packs died off from rabies in the 1990s, said Cleveland, and 30% of the lions died within six months when they became infected with another deadly canine disease - distemper.

The best means of protecting wild animals from outbreaks has been shown to be to create a cordon, or buffer, round the conservation area by vaccinating dogs in the adjacent villages.

What to do if you are bitten
  • Immediately wash the bite wound well, for 10 at least 10 minutes, with soap and clean running water.
  • Remember that most rabies cases result from an infected bite, but a scratch, or an animal licking broken skin can potentially also transmit the virus.
  • If there is any doubt that the animal may be rabid, consult your doctor immediately about getting a rabies vaccination. Rabies is more of a concern if you are bitten by a stray dog, a dog in a rural or impoverished area, or a wild animal, and if the animal appears sick or is behaving strangely. (A wild animal that acts tame; a tame animal that acts wild.) However a bite from ANY animal that may not have up-to-date vaccinations is a risk; this includes stray cats and wild animals being kept as pets. If you are bitten, you need to have proof from a veterinarian that the animal has been appropriately vaccinated - only then is it appropriate to skip PEP. Treatment is ineffective once symptoms of rabies occur.

  • World Rabies Day is 28 September 2014. Donations to help the fight against rabies can be made via the
    Global Alliance for Rabies Control.

    Read more:

    Rabies: fast facts
    Main diseases in dogs
    Clinic urges Ebola survivors to donate blood

Olivia Rose-Innes is Health24’s EnviroHealth Editor. Read more of her columns and articles or post a question to her expert forum.


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