Crisis biology: Can bacteria save bats and frogs from deadly diseases?

As populations plummet, biologists race for a solution.

  • Biologist Vance Vredenburg is one of several researchers turning to microbes in hopes of saving species threatened by disease.

    Anand Varma
  • Vredenburg swabs a Sierra Nevada yellow-legged frog to test for the presence of chytrid fungus in Kings Canyon National Park, California.

    Anand Varma
  • A little brown bat with white-nose syndrome in Greeley Mine, Vermont, March 26, 2009.

  • Dish A shows P. destructans (the fungus that causes white-nose syndrome in bats) spore growth after 21 days. Spores still grew in Dish B with unactivated R. rhodochrous bacteria. In Dish C, activated bacteria completely inhibited spore growth after 21 days. (When this experiment was conducted the, the fungus was named Geomyces destructans; it has since has been changed to Pseudogymnoascus destructans.)

    Christopher Cornelison
 

In 2007, Valerie McKenzie volunteered for a large study of human body bacteria. It was the dawn of the golden age of the microbe. Researchers were just beginning to understand how bacteria and other microbes in human intestines influence everything from obesity to allergies and infections. McKenzie, a University of Colorado-Boulder biologist, was mildly curious about her "microbiome." But she was more interested in the bacteria living on the skin of frogs and toads.

Amphibian populations worldwide are plummeting, and entire species are going extinct. The West's struggling species include boreal toads and mountain yellow-legged frogs. Invasive species and habitat degradation play a major role, but amphibians are dying even in places with good habitat. Batrachochytrium dendrobatidis, an aggressive fungus commonly known as chytrid, is often to blame.

McKenzie, who was studying the role of farmland conversion and suburbanization in the decline of leopard frogs in Colorado, suspected chytrid was also a factor. When she read a paper about a strain of bacteria found on red-backed salamanders that inhibited chytrid's growth, she began to wonder: What microbes lived on the skin of her frogs and toads? And could any of them fight chytrid?

She captured boreal toads and leopard frogs and swabbed their legs, feet and bellies at research sites near Boulder and Meeker, Colo. She took the samples to Rob Knight, a fellow CU-Boulder biologist who studies the human microbiome. In exchange for DNA analyses of the bacteria on her amphibians, McKenzie volunteered for Knight's study, handing over fecal samples and forehead, armpit and hand swabs. "I was like, 'Whatever you want, can you just run some of my frog samples?' " she laughs. "That's how I got my first data set."

McKenzie and others now hope to harness the breakthroughs of the human-microbe revolution to slow two of wildlife's most prolific – and seemingly unstoppable – modern killers: chytrid, "the worst infectious disease ever recorded among vertebrates," according to the International Union for Conservation of Nature, and white-nose syndrome, a fungal disease that has killed more than 5.7 million bats in North America since 2006.

"When you see almost 99 percent of your population perished on the (cave) floor, it's incredibly alarming," says Tina Cheng, a University of California-Santa Cruz Ph.D. student who studies white-nose syndrome. "People are desperate for solutions."

Chytrid is a cruel and efficient killer. It spreads through water and skin-to-skin contact – during mating, for instance – infecting amphibians' skin, reducing their ability to absorb water and disrupting electrolyte levels enough to cause major organ failure. In weeks, it can obliterate populations.

Scientists suspect the disease is so devastating because most amphibians have never encountered this strain of the fungus before. Humans likely transported it around the globe in the pet trade, on American bullfrogs, whose legs are a delicacy, or on African clawed frogs, which doctors used for pregnancy tests until the 1970s. (The frog laid eggs when injected with a pregnant woman's urine.) Scientists first linked mass mortalities to chytrid in Australia and Central America in the late 1990s. It's since driven more than 200 species to collapse or extinction and colonized every continent except Antarctica.

High Country News Classifieds
  • MARKETING COMMUNICATIONS MANAGER
    High Country News, an award-winning media organization covering the communities and environment of the Western United States, seeks a Marketing Communications Manager to join our...
  • EDITOR-IN-CHIEF
    High Country News, an award-winning media organization covering the communities and environment of the Western United States, seeks an Editor-In-Chief to join our senior team...
  • RESEARCH FELLOW (SOUTHWESTERN U.S. ENERGY TRANSITION)
    The Institute for Energy Economics and Financial Analysis (IEEFA) in partnership with the Grand Canyon Trust is seeking a full-time Fellow to conduct topical research...
  • LENDER OWNED FIX & FLIP
    2 houses on 37+ acres. Gated subdivision, Penrose Colorado. $400k. Possible lender financing. Bob Kunkler Brokers Welcome.
  • ONCE OR TWICE
    A short historical novel set in central Oregon based on the the WWII Japanese high altitude ballon that exploded causing civilian casualties. A riveting look...
  • HISTORIC LODGE AND RESTAURANT - FULLY EQUIPPED
    Built in 1901, The Crazy Mountain Inn has 11 guest rooms in a town-center building on 7 city lots (.58 acres). The inn and restaurant...
  • HOUSE FOR SALE
    Rare mountain property, borders National Forest, stream nearby. Pumicecrete, solar net metering, radiant heat, fine cabinets, attic space to expand, patio, garden, wildlife, insulated garage,...
  • COMMUNITY ORGANIZER- NORTHERN PLAINS RESOURCE COUNCIL
    Want to organize people to protect Montana's water quality, family farms and ranches, & unique quality of life with Northern Plains Resource Council? Apply now-...
  • CONSERVATION MANAGER
    The Rio Grande Headwaters Land Trust (RiGHT) is hiring an energetic and motivated Conservation Manager to develop and complete new conservation projects and work within...
  • POLLINATOR OASIS
    Seeking an experienced, hardworking partner to help restore a desert watershed/wetland while also creating a pollinator oasis at the mouth of an upland canyon. Compensation:...
  • ELLIE SAYS IT'S SAFE! A GUIDE DOG'S JOURNEY THROUGH LIFE
    by Don Hagedorn. A story of how lives of the visually impaired are improved through the love and courage of guide dogs. Available on Amazon.
  • COMING TO TUCSON?
    Popular vacation house, furnished, 2 bed/1 bath, yard, dog-friendly. Lee at [email protected] or 520-791-9246.
  • NORTHEASTERN UNIVERSITY
    All positions available: Sales Representative, Accountant and Administrative Assistant. As part of our expansion program, our University is looking for part time work from home...
  • RUBY, ARIZONA CARETAKER
    S. Az ghost town seeking full-time caretaker. Contact [email protected] for details.
  • EXECUTIVE DIRECTOR
    Powder River Basin Resource Council, a progressive non-profit conservation organization based in Sheridan, Wyoming, seeks an Executive Director, preferably with grassroots organizing experience, excellent communication...
  • ADOBE HOME
    Passive solar adobe home in high desert of central New Mexico. Located on a 10,000 acre cattle ranch.
  • EXECUTIVE DIRECTOR
    Eastern Nevada Landscape Coalition, based in Ely, Nevada is looking for a new executive director to replace the long-time executive director who is retiring at...
  • STEVE HARRIS, EXPERIENCED PUBLIC LANDS/ENVIRONMENTAL ATTORNEY
    Comment Letters - Admin Appeals - Federal & State Litigation - FOIA -
  • LISA MACKEY PHOTOGRAPHY
    Fine Art Gicle Printing. Photo papers, fine art papers, canvas. Widths up to 44". Art printing by an artist.
  • LOG HOME IN THE GILA WILDERNESS
    Beautiful hand built log home in the heart of the Gila Wilderness on five acres. Please email for PDF of pictures and a full description.