Not only are they the only mammals that can fly, but bats also show off with their immunity to viruses and other diseases. What gives?

Well, according to a recent study in Science, these two abilities—flight and immunity—might be related in the winged animals.

A group of international researchers sequenced the entire genomes of two species of bats—the fruit bat Pteropus alecto and the insectivore Myotis davidii. These two species are from the two distinct sub-orders of bats—P. alecto is a megabat and M. davidii, a microbat. By comparing and contrasting the two species’ genomes and those of other mammals (human, rhesus macaque, mouse, rat, dog, cat, cow, and horse), the scientists could refine bats’ place in the tree of life as well as determine the evolution of some of their bat-traits.

Study co-author Chris Cowled, of the Australian Animal Health Laboratory, describes how remarkable these traits are. “Bats are a natural reservoir for several lethal viruses, such as Ebola and SARS, but they often don’t succumb to disease from these viruses. They also live a long time compared to animals similar in size.”

It turns out the trick for this trait is flight. Flying is a very energy intensive activity that also produces toxic by-products, and bats have developed some novel genes to deal with the toxins. Some of these genes are implicated in the development of cancer or the detection and repair of damaged DNA.

“What we found intriguing was that some of these genes also have secondary roles in the immune system,” says Cowled. “We’re proposing that the evolution of flight led to a sort of spill over effect, influencing not only the immune system, but also things like aging and cancer.

“A deeper understanding of these evolutionary adaptations in bats may lead to better treatments for human diseases, and may eventually enable us to predict or perhaps even prevent outbreaks of emerging bat viruses,” says Cowled.

Sounds bat-tastic.

Image: James Niland/Wikipedia

A group of scientists who study biodiversity and infectious diseases, reviewed several dozen research papers published in the last five years and found a link between biodiversity loss and an increase in transmittable disease.  Specifically, they discovered that species losses in ecosystems from forests to fields results in increased pathogens in the system.

The pattern holds true for various types of pathogens—viruses, bacteria, fungi—and for many types of hosts, whether humans, other animals, or plants. The researchers found two familiar human diseases that fit this pattern—West Nile virus and Lyme disease.

Sadly, the animals, plants, and microbes most likely to disappear as biodiversity is lost are often those that buffer infectious disease transmission. Those that remain tend to be species that magnify the transmission of infectious diseases.

In one example, three different studies found strong links between low bird diversity and increased occurrence of West Nile encephalitis in the United States. Ecosystems with low bird diversity contained bird species more susceptible to the virus; thus increasing infection rates in mosquitoes and people. In comparison, ecosystems that contained a higher diversity of birds had many species that were unfit as hosts for the virus.

The authors are hoping these results will spur action. For humans and other species to remain healthy, it will take more than a village—we need an entire planet, the scientists say, one with its diversity thriving.

Global biodiversity has declined at an unprecedented pace since the 1950s. Current extinction rates are estimated at 100 to 1,000 times higher than in past epochs, and are projected to increase at least a thousand times more in the next 50 years.

“When a clinical trial of a drug shows that it works,” says lead author Felicia Keesing of Bard College, “the trial is halted so the drug can be made available. In a similar way, the protective effect of biodiversity is clear enough that we need to implement policies to preserve it now.”

Image of West Nile virus by PhD Dre/Wikipedia