Bats, viruses and longevity: what's the link?

From the discovery of Hendra virus in Australia in 1994 to the ongoing outbreaks of MERS virus in the Middle East and SARS in West Africa, we have witnessed the emergence of several important new infectious diseases in the last two decades. Many of them are bat-borne zoonotic agents, including Hendra, Nipah, Ebola, Marburg, SARS and probably MERS as well. Bats are increasingly being recognised as one of the most important reservoir hosts for emerging zoonotic viruses. Although these viruses are highly pathogenic in human and other mammals, none of them seem to be able to cause diseases in bats. Surveillance studies around the world further indicate that bat-borne viruses are present at a higher prevalence and with greater genetic diversity than viruses found in other mammals. Bats have been known for their longevity in comparison to other mammals of similar body size. Most bats can live 3-10 times longer than other mammals despite their high rate of heart beat and metabolism, both of which are known to have a negative impact on aging. Our recent comparative genomics study and investigation into the immune, inflammation and tumour suppression systems seem to suggest that the evolutionary adaptation to flight may have lead bats to become a group of animals which not only live longer and are less prone to cancer, but also are better adapted to coexist with viruses (pathogens) without clinical diseases.