Whitenose syndrome (Pseudogymnoascus destructans)

Synonyms: Geomyces destructans

Common Names: white-nose syndrome, WNS, white nose syndrome, bat white-nose fungus

Description:

White-nose syndrome is a deadly disease of hibernating bats caused by a cold-loving fungus, Pseudogymnoascus destructans [1][2]. The fungus grows on bats while they hibernate in cold caves and mines, leaving a white fuzz on the nose and wings and waking them too often, so they burn up the fat they need to survive winter and die [1][2]. MISIN tracks it because it has killed millions of North American bats, crashing some species by more than 90%, and because people can carry the fungus between caves on their gear [1][2].

Identification:

White-nose syndrome is a disease, so you recognize it by its effects on bats rather than by something you can pick up. The classic sign is a white, fuzzy or powdery growth of fungus on the muzzle (giving the disease its name), and often on the ears and wings, of bats during winter hibernation [1][2]. The fungus also makes bats behave abnormally in winter: they wake too often, fly outside in cold or daylight, cluster near the entrances of caves and mines, and are often found dead or dying in or near these sites in late winter [1][2]. The fungus is cold-loving ? it grows only in cold conditions and cannot grow above about 68 ?F (20 ?C), which is why it attacks bats while their bodies are cold during hibernation [2].

Signs are easiest to see in late winter and early spring, near the end of hibernation, when affected bats show the white growth, behave strangely, or die [1][2]. The disease takes hold in the cold, humid caves and mines where bats overwinter [2].

At-a-glance cues:

1. White, fuzzy or powdery fungus on the nose, ears, or wings of hibernating bats [1][2]
2. Bats flying outside in cold weather or daytime in winter, or clustering near cave or mine entrances [1][2]
3. Dead or dying bats in or near caves and mines in late winter [1][2]
4. Signs most visible in late winter and early spring [1][2]

Habitat:

White-nose syndrome lives where bats hibernate. The fungus thrives in the cold, humid conditions of underground bat hibernation sites ? caves and abandoned mines (called hibernacula) ? and it can persist in the soil and sediment there even when bats are gone [2]. Its hosts are hibernating bats, including the little brown bat, northern long-eared bat, tricolored bat, and Indiana bat, among others [1].

The fungus is believed to have been introduced to North America from Europe or Asia, where bats appear to tolerate it; its exact native range is still uncertain [2]. It was first documented in New York in the winter of 2005?2006 and has since spread across much of eastern North America and into the West [1][2]. It continues to expand into new regions, including the Midwest [1].

Reproduction:

White-nose syndrome spreads in two main ways. Most spread is bat-to-bat: the fungus passes between bats packed together in a hibernation site, and it lingers in the cave or mine soil to infect bats in later years [2]. The other way is the one people control: the fungus's spores can hitch a ride on clothing, footwear, and caving gear, and be carried from an infected cave or mine to a clean one [1][2]. This human pathway is why following cave closures and cleaning gear matters so much [1].

There is no "seed-set" window to target as with a weed. The fungus reproduces by spores in cold conditions, and the practical steps are about not spreading it and not disturbing bats: stay out of closed hibernation sites, decontaminate gear between caves, and report sick or dead bats (see Management) [1][2].

Impact and Damage:

The fungus that causes white-nose syndrome is not known to harm people, pets, or other animals besides bats [1]. (As a general safety note, never handle any bat with bare hands, because bats can carry rabies.) The damage from this disease is to bats ? and it has been catastrophic [1].

White-nose syndrome is one of the most lethal wildlife diseases ever recorded, killing millions of bats across North America since 2006 and wiping out more than 90% of northern long-eared, little brown, and tricolored bats in some regions in under a decade [1]. Because these bats eat enormous numbers of insects each night, losing them ripples outward ? more insect pests for farms and forests, and the loss of a natural form of pest control worth a great deal to agriculture [1][2]. The collapse of these once-common bats has reshaped the wildlife of affected caves and the surrounding landscape [1].

Similar species:

White-nose syndrome is fairly distinctive ? there is no commonly confused species in the MISIN region. The white fungal growth on a hibernating bat's nose and wings is the key sign, but it can be mistaken for harmless moisture, condensation, or ordinary mold on a bat (including mold on a bat that has already died of another cause). Because of this, and because the fungus is microscopic, a suspected case is confirmed by laboratory testing rather than by sight alone.

Monitoring and rapid response:

Signs to watch for:

1. White, fuzzy or powdery fungus on the nose, ears, or wings of hibernating bats, most visible in late winter and early spring [1][2]
2. Bats flying outside in cold weather or in daytime in winter, or clustering near cave or mine entrances [1][2]
3. Dead or dying bats in or near caves, mines, or buildings in late winter [1][2]

What you can do:

1. Do not disturb hibernating bats ? stay out of caves and mines that are closed to protect bats, and avoid entering bat hibernation sites in winter, since waking bats can kill them [1][2].
2. If you visit caves or mines, follow all posted closures and decontaminate your clothing, footwear, and gear between sites so you do not carry the fungus's spores [1][2].
3. Do not handle bats (they can carry rabies); if you find sick or dead bats, or bats acting strangely in winter, leave them alone, photograph them, and report them (below) and to your state wildlife agency [1].
4. If bats roost in your barn or attic, avoid disturbing them ? especially in winter ? and report any unusual die-off [1].
5. Cavers, crews, and land managers should follow the national decontamination protocol between every site, support cave-access management, and coordinate any hibernaculum monitoring with wildlife biologists [1][2].

When to call a professional:

1. Any suspected white-nose syndrome, a bat die-off, or bats that need to be removed from a building ? contact your state wildlife agency or a wildlife professional rather than handling bats yourself [1].
2. For chemical control options, contact a licensed applicator or your local cooperative extension office.

Report sightings to MISIN. Help track this species' spread by submitting observations through the MISIN web site or the MISIN mobile app (Android, iOS, Windows, and macOS). Photos at multiple angles paired with a precise GPS location are the most valuable data for confirming new occurrences and triggering rapid-response review.

Credits:

1. USDA National Invasive Species Information Center. White-Nose Syndrome. invasivespeciesinfo.gov
2. U.S. Geological Survey. What is White-nose Syndrome? usgs.gov
3. U.S. National Park Service. What Is White-nose Syndrome? nps.gov

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