Fungus That Causes White-nose Syndrome in Bats Detected in Texas
Texas Parks and Wildlife
Earlier this year, Texas Parks and Wildlife Department (TPWD) announced that the fungus that causes deadly white-nose syndrome (WNS) in hibernating bats has been detected in Texas for the first time. The syndrome has killed millions of bats in the eastern parts of North America, raising national concern. A coalition of groups in Texas is continuing work to monitor the spread of the problem and is seeking willing landowners who could help scientists locate and access bat caves.
The fungus was detected on species of hibernating bats in six North Texas Counties: Childress, Collingsworth, Cottle, Hardeman, King, and Scurry. The three species are tri-colored bat, cave myotis, and Townsend’s big-eared bat. This is the first detection of the fungus on both cave myotis and Townsend’s big-eared bats. The Townsend’s big-eared bat has an isolated subspecies in the East, the Virginia Big Eared Bat that has already tested positive for the fungus.
Samples were collected between Jan. 11 and Feb. 22 by biologists from Bat Conservation International (BCI) and Texas A&M University’s (TAMU) Department of Wildlife and Fisheries Sciences and Institute of Renewable Natural Resources, and analyzed as part of a National Science Foundation-funded project led by University of California at Santa Cruz. Surveys of sites in seven other counties in 2017 did not detect the fungus — those counties are Coryell, Freestone, Leon, Panola, San Saba, Shelby, and Wheeler.
White-nose syndrome is caused by the fungus Pseudogymnoascus destructans (Pd) and is responsible for the deaths of millions of bats in the United States and Canada. It has been expanding in all directions since its discovery in New York in 2007. In some states, there have been declines in winter bat numbers of greater than 90 percent.
“There is still hope for bats in Texas,” said Jonah Evans, Texas Parks and Wildlife Department state mammologist. “The fungus thrives in colder climates and it remains to be seen if WNS will have the same serious impacts in Texas as it has in northern states. Additionally, 20 of the 32 species of bats in Texas do not regularly hibernate and we are hopeful they will not suffer significant population declines. We will continue working with cooperating landowners and researchers to implement the best management tools available to conserve these species.”
Bats play an important role in the ecosystem by consuming large numbers of insects. Recent studies have shown that the agricultural value of insect control by bats is $1.4 billion annually in Texas alone. This value includes reduced crop loss to insect pests, reduced spread of crop diseases, and reduced need for pesticide application.
White-nose syndrome does not infect humans and is only known to affect hibernating bats. The fungus thrives in cold, humid environments and invades the skin of bats, disrupting their hibernation and depleting their fat stores. Migratory Mexican free-tailed bats, which roost in the millions at popular sites such as Bracken Bat Cave, the Congress Avenue Bridge in Austin, and Old Tunnel State Park, do not hibernate for long periods during the winter, and are not expected to be at high risk for the disease. Although there is no known cure for white-nose syndrome, wildlife disease experts are actively working on several treatments to help improve survival.
Today’s announcement of Pd in Texas brings the total number of states with the fungus to 33. Of those states, 30 have been confirmed with white-nose syndrome.
“This discovery is significant because it occurs where the ranges of eastern, southern, and western bat species intersect, and two of these bats have extensive distributions in Central America and the West – beyond the current range of the disease,” said Jeremy Coleman, national white-nose syndrome coordinator for the U.S. Fish and Wildlife Service, who leads a coalition of more than 100 state, federal, and international governments agencies, academics, and non-governmental organization working to defeat white-nose syndrome. “While we don’t know how new species of western hibernating bats will respond to the fungus, we are concerned about this move into the West.”
While scientists are disappointed by the detection of Pd in Texas, its arrival is not unexpected. The fungus was detected in Oklahoma in 2015 and Arkansas in 2014. Texas Parks and Wildlife Department (TPWD) has closely coordinated with state and federal agencies as the fungus has spread toward the state. TPWD has worked with BCI to monitor Panhandle caves for the disease since 2011 and in 2015 TPWD funded a statewide project through TAMU aimed at early detection of the disease and describing bat populations before white-nose syndrome arrives.
Nationally, Coleman said the partners in the international response are working to develop tools to manage WNS and improve bat survival. Management solutions are in development to slow the spread of Pd to unaffected areas, improve the survival of bats in newly affected areas, and promote recovery of populations decimated by WNS. Treatment options that could be deployed in some affected areas in the future are also a research focus of the international response team.
TPWD is working with researchers at TAMU to survey caves with hibernating bats. They are asking for willing landowners for help locating and accessing bat winter roosts and caves for tracking the spread of the fungus. Those with knowledge of such sites are asked to contact TPWD at 512-389-4505.
Wildlife experts say cavers and landowners with caves can help prevent human assisted spread of the fungus by requiring cave visitors to abide by the decontamination protocols described at: https://www.whitenosesyndrome.org/topics/decontamination.
Frequently Asked Questions
What is White-nose syndrome?
White-nose syndrome is a disease that is killing hibernating bats in eastern North America. WNS was first documented at four sites in eastern New York 2007. After that, photographs taken in February 2006 were found, showing affected bats at another site.
Named for the white fungus on the muzzles and wings of affected bats, WNS has rapidly spread to many sites throughout the eastern United States and into Canada. The fungus that causes WNS has been detected as far south as Mississippi. Researchers associate WNS with the newly identified fungus, Pseudogymnoascus destructans, which thrives in cold and humid conditions characteristic of caves and mines used by bats.
Bats affected with WNS do not always have obvious fungal growth, but they may behave strangely within and outside of their hibernacula (caves and mines where bats hibernate during the winter).
What species of bats are affected?
White-nose syndrome (WNS) is known to predominantly affect hibernating bats. More than half of the 47 bat species living in the United States and Canada rely on hibernation for winter survival.
Nine bat species, including two endangered species and one threatened species, have been confirmed with white-nose syndrome in North America. The causative fungus has been found on an additional six species, including one endangered species, without confirmation of the disease.
Confirmed: Bat species identified with diagnostic symptoms of WNS:
- Big brown bat
- Eastern small-footed bat
- Gray bat
- Indiana bat
- Little brown bat
- Northern long-eared bat
- Southeastern bat
- Tricolored bat
- Yuma bat
Pd positive: Bat species and subspecies on which P.d. has been detected, but no diagnostic sign of WNS has been documented:
- Eastern red bat
- Silver-haired bat
- Rafinesque’s big-eared bat
- Virginia Big-Eared Bat
- Cave bat
- Townsend’s big-eared bat
Where has white-nose syndrome been observed?
White-nose syndrome has been confirmed in bat hibernation sites in 31 states and 5 Canadian provinces. In addition, the fungus that causes white-nose syndrome, Pseudogymnoascus destructans, has been found in two additional states: Mississippi and Texas.
How is white-nose syndrome transmitted?
Scientists believe that white-nose syndrome is transmitted primarily from bat to bat. There is a strong possibility that it may also be transmitted by humans inadvertently carrying the fungus from cave to cave on their clothing and gear.
Is global climate change a possible cause of white-nose syndrome?
While many possible causes of white-nose syndrome are being studied, no credible evidence links climate change and WNS. Weather conditions in caves and mines where bats hibernate were stable during when WNS emerged, and no data show changes in insect prey numbers in affected areas. Potential impacts of global climate change will continue to be monitored as we learn more about the disease.
What is the effect of white-nose syndrome on bats?
We have seen 90 to 100 percent mortality of bats (mostly little brown bats) at hibernacula in the northeastern United States. However, mortality may differ by site and by species within sites.
The endangered Indiana bat hibernates in many affected sites. We are closely monitoring Indiana bat populations in many hibernacula and, to the extent possible, in their summer maternity colonies. During the winter of 2008-2009, biologists conducted the biennial rangewide winter counts of Indiana bats. Population estimates based on this count show the overall Indiana bat population declined by approximately 17 percent. This is the first observed decline since 2001.
In addition to the Indiana bat, white-nose syndrome has reached the ranges of three more endangered bats: gray bats, Virginia big-eared bats and Ozark big-eared bats. The Northern long-eared bay was listed as threatened in 2015, the first bat species to be listed due to the effects of white-nose syndrome. We are closely monitoring these species as WNS continues to spread.
White-Nose Syndrome
Does white-nose syndrome pose a risk to human health?
Thousands of people have visited affected caves and mines since white-nose syndrome was first observed, and there have been no reported human illnesses attributed to WNS. We are still learning about WNS, but we know of no risk to humans from contact with WNS-affected bats. However, we urge taking precautions and not exposing yourself to WNS. Biologists and researchers use protective clothing when entering caves or handling bats.
What should cavers know and do?
The U.S. Fish and Wildlife Service and the states request that cavers observe all cave closures and advisories, and avoid caves, mines or passages containing hibernating bats to minimize disturbance to them. The Service asks that cavers and cave visitors stay out of all caves in the affected states and adjoining states to help slow the potential spread of white-nose syndrome. Local and national cave groups have also posted information and cave advisories on their websites.
What should you do if you find dead or dying bats, or if you observe bats with signs of white-nose syndrome?
- The Center for Disease Control has additional information for collecting and disposing of dead bats.
- Contact your state wildlife agency, file an electronic report in those states that offer this service, e-mail U.S. Fish and Wildlife Service biologists in your area (http://whitenosesyndrome.org/contacts), or contact your nearest Service field office (find locations at http://www.fws.gov/offices/) to report your potential WNS observations.
- It is important to determine the species of bat, in case it is a federally protected species. Photograph the potentially affected bats (including close-up shots, if possible) and send the photograph and a report to a state or Service contact (above).
- If you need to dispose of a dead bat found on your property, first BE CERTAIN THE BAT IS DEAD. Use a trowel or other tool to scoop the dead bat into a plastic bag. If you must use your hands, wear a heavy leather glove covered with a plastic bag or disposable glove to pick it up. Place both the bat and the bag or disposable glove into another plastic bag, close the bag securely, spray with disinfectant, and dispose of it with your garbage. Thoroughly wash your hands and any clothing that comes into contact with the bat.
- If you see a band on the wing or a small device with an antenna on the back of a bat (living or dead), contact your state wildlife agency or your nearest Service field office, as these are tools biologists use to identify individual bats.
What are signs of white-nose syndrome?
Bats may lose their fat reserves, which they need to survive hibernation, long before the winter is over. They often leave their hibernacula during the winter and die. As winter progresses, increasing numbers of dead bats have been found at many affected locations.
- White-nose syndrome may be associated with some or all of the following unusual bat behavior:
- White fungus, especially on the bats’ nose, but also on the wings, ears or tail;
- Bats flying outside during the day in temperatures at or below freezing;
- Bats clustered near entrances of hibernacula; and
- Dead or dying bats on the ground or on buildings, trees or other structures.
Hibernating bats may have other white fungus not associated with WNS. If a bat with fungus is not in an affected area and has no other signs of WNS, it may not have WNS.
What are federal and state agencies doing to fight white-nose syndrome?
An extensive network of state and federal agencies is working to investigate the cause, source and spread of bat deaths associated with white-nose syndrome, and to develop management strategies to minimize the impacts of WNS.
The overall WNS investigation has three primary focus areas: research, monitoring/management and outreach. For example, the U.S. Fish and Wildlife Service is conducting winter surveys to document and track affected sites, working with the caving community and local cave owners to target potential sites for surveys and protective measures, and securing funding to identify and fund research on the spread and management of WNS.
In 2009 and 2010, the Service led a team of federal and state agencies and tribes in preparing a national white-nose syndrome management plan to address the threat to hibernating bats. The plan provides a framework for coordinating and managing the national investigation and response to WNS. The National Plan for Assisting States, Federal Agencies, and Tribes in Managing White-Nose Syndrome in Bats finalized in May 2011, outlines the actions necessary for state, federal and tribal coordination, and provides an overall strategy for investigating the cause of WNS and finding ways to manage it.
What is the purpose of the national plan?
As WNS spreads, the challenges facing wildlife managers in understanding threats to bat populations and managing WNS continue to increase. Collaboration among state, federal and tribal wildlife management agencies and NGOs is essential to the effectiveness of the collective response and ultimately to the survival of bat species across North America.
The national plan provides a framework for coordinating and managing the national investigation and response to WNS. The plan outlines the actions necessary for state, federal, and tribal coordination, and provides overall strategy for investigating the cause of WNS and finding ways to manage it.