A disease impacting bat colonies in North America has yet to surface in Colorado. However, a new study is giving hope to local wildlife biologists on the look-out for potential outbreaks.
Bats with the white-nose syndrome are prone to immune reconstitution inflammatory syndrome (IRIS), a virus that is similar to AIDS, according to the study conducted by the U.S. Geological Survey and the National Institutes of Health.
It's bad news for many bats in general, but perhaps not for Colorado's colonies. Because IRIS increases the rapidity of bat mortality, infected bats are less likely to travel abroad, according to Tina Jackson, a species conservation coordinator for the Colorado Parks and Wildlife Department.
"I'm very worried about the white-nose syndrome outbreak," Jackson said. "It's currently our understanding that it would only take one infected bat for cases of IRIS and white-nose to start occurring - this new virus could quicken the spread or it could cause a more rapid die-off of bats with WNS, which would actually be better for keeping the infection out of Colorado."
The connection between the two syndromes could help physicians to find ways to treat human AIDS patients. It would also help wildlife researchers in Colorado to become more proactive in keeping the disease out of the state.
So far the state's efforts to keep white-nose syndrome out of the area, including monitoring of caves in Colorado, have been successful. In other states, however, researchers are finding that bats that would have survived the syndrome are succumbing to another virus following their recovery.
This condition was first described in HIV-AIDS patients. However, the infected bats are the first non-human occurrence of IRIS ever observed, said Carol Meteyer, author of the study.
"IRIS is a syndrome which an organism's immune system, having been suppressed for a time, reactivates," Meteyer said. "Perceiving a serious infection around it, the body goes into overdrive resulting in severe inflammation and tissue damage in infected areas."
With bats, IRIS causes wing tissue to become damaged during hibernation. So, even if a bat recovers from the white-nose syndrome, if it has become infected by IRIS the likelihood of death increases.
Local wildlife biologists say they're still in "the wait and see stage" of dealing with white nose syndrome and new IRIS outbreaks.
Jackson said the new study would not affect current efforts to keep outbreaks outside of the state.
In human patients with HIV-AIDS and bats with WNS, the functioning of the immune system is severely compromised. For both humans and bats, IRIS can be fatal, according to the study.
"For humans, this occurs when the HIV virus attacks the patient's white blood cells, and for bats, this occurs during normal hibernation," Meteyer said.
First described in humans with HIV-AIDS after patients with low counts of white blood cells the HIV virus attacks, bats with IRIS had increases in those cell numbers following treatment.
"The potential discovery of IRIS in bats infected with white-nose syndrome is incredibly significant in terms of understanding both the reasons for bat mortality and basic immune response," said Marcia McNutt, director with the U.S. Geological Survey. "This discovery could also prove significant for studies on treatment for AIDS."
In some patients, who had secondary bacterial or other opportunistic infections due to their suppressed immune system, their condition significantly worsened as the restoration in immune cell function resulted in an over-reaction that damages healthy tissue, Meteyer said.
In bats, IRIS might be a result of changes in immune system function during hibernation. During hibernation, all internal systems for the bats enter a reduced state, including the immune system, so as to conserve resources. The fungus that causes WNS will spread unchecked over the wings, muzzle and ears of bats.
If they survive the fungal infection through winter, when the bats emerge in the spring, they face a new challenge - intense inflammation in their wings that can be deadly.
Wildlife biologists say they'll still continue to monitor bats in the state to prevent WNS and IRIS from appearing locally.