White-Nose Syndrome
First detected near Albany, New York, in February 2006, white-nose syndrome has caused the death of more than 6.7 million bats in North America. White-nose syndrome is named for the characteristic white fungus (Pseudogymnoascus destructans, or Pd) which appears on the muzzle and wings of hibernating bats it infects.
Disease Distribution
Since the disease was initially detected, it has been confirmed in 35 states and 7 Canadian provinces. Pd, the fungus which causes the disease, has been detected in four additional states. Neither the disease nor the fungus which causes it have been detected in Louisiana.
Nationally, twelve bat species have been identified with diagnostic symptoms of white-nose syndrome; three of these species are found in Louisiana. Pd has been detected without diagnostic signs of white-nose syndrome in eight additional species, four of which are found in Louisiana. Again, neither the disease nor the fungus that causes it have been found in bats in Louisiana.
Clinical Signs
Pd is a psychrophilic (cold-loving) fungus which infects bats during their winter hibernation when their body temperatures decrease. Optimal conditions for growth of Pd are more humid environments with ambient temperatures of 32° to 59°°F (0° to 15?C). The fungus invades a bat’s hair follicles, tissue, and sebaceous and sweat glands and erodes ear and wing skin. Healthy wings allow bats to maintain water balance and are critical to homeostasis (appropriate internal body temperature and proper functioning of their body’s systems). As their skin is eroded, they become dehydrated and have electrolyte imbalances. As the fungus grows, bats are more frequently aroused—they are more active than usual and exhibit unusual behaviors such as flying outside during the day or clustering in areas where they hibernate. This increased activity during a normally inactive period reduces or completely depletes bats’ fat reserves critical for their survival during hibernation when food and water is limited, resulting in death.
Mass Mortality
Responsible for millions of bat deaths in North America, white-nose syndrome has resulted in 90 to 100% mortality in some areas where bats hibernate. Drastic declines in bat populations threaten regional extinction for some species, such as the little brown bat (Myotis lucifugus), once one of the most common species of bat in North America.
The spread of white-nose syndrome and associated population declines over the last decade can significantly impact the ecosystem. Bats aid in seed and pollen dispersal, contributing to plant diversity and forest regeneration in areas that are disturbed. Bats also control pests—insect-eating bat species can consume hundreds to thousands of insects per hour, including insects which are known vectors of disease to humans and other mammals and agricultural crop pests.
What We're Doing about It
LDWF monitors areas where bats are known to roost and hibernate and conducts annual Pd and white-nose syndrome surveillance. To date, we have detected neither in Louisiana. Laboratory testing is required to confirm the presence of Pd. White-nose syndrome can be diagnosed by clinical symptoms, but laboratory testing is required for confirmation.
