Bats are living up to their frightening reputation in the world’s worst Ebola outbreak as prime suspects for spreading the deadly virus to humans, but scientists believe they may also shed valuable light on fighting infection.

Bats can carry more than 100 different viruses, including Ebola, rabies and severe acute respiratory syndrome (Sars), without becoming sick themselves.

While that makes them a fearsome reservoir of disease, especially in the forests of Africa where they migrate vast distances, it also opens the intriguing possibility that scientists might learn their trick in keeping killers like Ebola at bay.

“If we can understand how they do it then that could lead to better ways to treat infections that are highly lethal in people and other mammals,” said Olivier Restif, a researcher at the University of Cambridge in Britain.

Clues are starting to emerge following gene analysis, which suggest bats’ capacity to evade Ebola could be linked with their other stand-out ability – the power of flight.

Flying requires the bat metabolism to run at a very high rate, causing stress and potential cell damage, and experts think bats may have developed a mechanism to limit this damage by having parts of their immune system permanently switched on.

The threat to humans from bats comes en route to the dinner plate. Bushmeat – from bats to antelopes, squirrels, porcupines and monkeys – has long held pride of place on menus in West and Central Africa. The danger of contracting Ebola lies in exposure to infected blood in the killing and preparation of animals.

Scientists studying Ebola since its discovery in 1976 in the Democratic Republic of Congo, then Zaire, have long suspected fruit bats as being the natural hosts, though the link to humans is sometimes indirect as fruit dropped by infected bats can easily be picked up by other species, spreading the virus to animals such as monkeys. This nexus of infection in wildlife leads to sporadic Ebola outbreaks following human contact with blood or other infected animal fluids.

This no doubt happened in the current outbreak, although the scale of the crisis now gripping Liberia, Sierra Leone and Guinea, which has killed around 5,000 people, reflects subsequent public health failures.

“What is happening now is a public health disaster rather than a problem of wildlife management,” said Marcus Rowcliffe at the Zoological Society of London, which runs London Zoo.

Bats’ role in spreading Ebola is probably a function both of their huge numbers, where they rank second only to rodents among mammals in the world, as well as their unusual immune system, according to Michelle Baker of the Commonwealth Scientific and Industrial Research Organisation, Australia's national science agency.