|
30 April 2008
Study shows ape diseases are biggest threat to humans
Research from the Universities of Sheffield, UK, and California, USA, which shows why infectious diseases and viruses spread from one species to another, could provide a vital tool in predicting future trends of emerging diseases in humans.
The findings, published in Proceedings of the Royal Society B:Biological Sciences, shows that infectious diseases are most often shared between species which are closely related and inhabit the same geographic region. Therefore, humans may be most vulnerable to diseases from the great apes, which includes chimpanzees and gorillas, because these species represent our closest relatives.
According to the researchers, humans are almost four times more likely to share diseases and viruses with chimpanzees, which last shared a common ancestor with humans around 8 million years ago, than with a colobus monkey, which diverged from humans over 34 million years ago.
The researchers suggest that close proximity to infected species can increase the risk of a disease jumping from one species to another but that the host´s biology determines whether the disease spreads in a new host.
They also found that viruses were more adept at jumping between distantly related host species, so that geographical proximity rather than evolutionary relatedness determines the spread of viral diseases. For example, Bird Flu and West Nile Virus in birds, and Hendra virus in bats, are all viral diseases that have jumped large evolutionary distances to infect humans.
Amy Pedersen, a research fellow in the University of Sheffield´s Department of Animal and Plant Sciences, and co-author of the study, said: "Our study is important because emerging infectious diseases are increasing in number, cause high mortality, and frequently originate from animals. We suggest hotspots of future emerging diseases may be found where humans come into close proximity with wild primates as is increasingly the case in the forests of Central and West Africa, due to rapidly growing human populations and scarcity of resources in the region.
"Our research also suggests that we are likely to see an increase in outbreaks of novel viral diseases as humans invade previously isolated habitats, and these may be as likely to jump from a rat or a bat, as an ape."
Dr Jonathan Davies, from the National Center for Ecological Analysis and Synthesis at the University of California, and co-author of the study, said: "Infectious diseases crossing species barriers pose a huge and increasing threat to human health and the conservation of wild species. Our study helps us to understand where and how diseases jump between species, and provides a critical first step in predicting future outbreaks."
|
