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
  • GRAND CANYON DIRECTOR
    The Grand Canyon director, with the Grand Canyon manager, conservation director, and other staff, envisions, prioritizes, and implements strategies for the Grand Canyon Trust's work...
  • ADMINISTRATIVE ASSISTANT
    Great Old Broads for Wilderness seeks a part-time Administrative Assistant to support the organization's general operations. This includes phone and email communications, office correspondence and...
  • 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...
  • ONE WILL: THREE WIVES
    by Edith Tarbescu. "One Will: Three Wives" is packed with a large array of interesting suspects, all of whom could be a murderer ... a...
  • PROGRAM DIRECTOR, SALAZAR CENTER FOR NORTH AMERICAN CONSERVATION
    The Program Director will oversee the programmatic initiatives of The Salazar Center, working closely with the Center's Director and staff to engage the world's leading...
  • WILDEARTH GUARDIANS - WILD PLACES PROGRAM DIRECTOR
    Salary Range: $70,000-$80,000. Location: Denver, CO, Portland, OR, Seattle, WA, Missoula, MT or potentially elsewhere for the right person. Application Review: on a rolling basis....
  • RIVER EDUCATOR/GUIDE + TRIP LEADER
    Position Description: Full-time seasonal positions (mid-March through October) Organizational Background: Colorado Canyons Association (CCA) is a 10 year old nonprofit organization fostering community stewardship of...
  • BOOKKEEPER/ADMINISTRATIVE ASSISTANT
    Position Description: Part-time, year-round bookkeeping and administration position (12 - 16 hours/week) $16 - $18/hour DOE Organizational Background: Colorado Canyons Association (CCA) is a 10...
  • LAND STEWARD
    San Isabel Land Protection Trust seeks a full-time Land Steward to manage and oversee its conservation easement monitoring and stewardship program for 42,437 acres in...
  • EXECUTIVE DIRECTOR
    Ventana Wilderness Alliance is seeking an experienced forward-facing public land conservation leader to serve as its Executive Director. The mission of the Ventana Wilderness Alliance...
  • COMMUNICATIONS AND DEVELOPMENT DIRECTOR
    The Quivira Coalition (www.quiviracoaltion.org) is a Santa Fe-based nonprofit that builds resilience on arid working lands. We foster ecological, economic, and social health through education,...
  • GRANT WRITER
    "We all love this place we call Montana. We believe that land and water and air are not ours to despoil, but ours to steward...
  • DEVELOPMENT DIRECTOR
    The Development Director is responsible for organizing and launching a coherent set of development activities to build support for the Natural History Institute's programs and...
  • WILDLIFE PROJECT COORDINATOR
    Founded in 1936, the National Wildlife Federation (NWF or Federation) is America's largest and most trusted grassroots conservation organization with 53 state/territorial affiliates and more...
  • EXECUTIVE DIRECTOR
    The Cinnabar Foundation helps protect and conserve water, wildlife and wild lands in Montana and the Greater Yellowstone Ecosystem by supporting organizations and people who...
  • TRUSTEE AND PHILANTHROPY RELATIONS MANGER,
    Come experience Work You Can Believe In! The Nature Conservancy in Alaska is seeking a Trustee and Philanthropy Relations Manager. This position is critical to...
  • EXECUTIVE DIRECTOR AT FRIENDS OF CEDAR MESA
    -The Land, History, and People of the Bears Ears Region- The Bears Ears and Cedar Mesa region is one of the most beautiful, complex, diverse,...
  • CONSERVATION SPECIALIST
    Position will remain open until January 31, 2021 Join Our Team! The New Mexico Land Conservancy (NMLC) is a non-profit land trust organization dedicated to...
  • OLIVERBRANCH CONSULTING
    Non-Profit Management Professional specializing in Transitional Leadership, Strategic Collaborations, Communications and Grant Management/Writing.
  • GREAT VIEWS, SMALL FOOTPRINT
    Close to town but with a secluded feel, this eco-friendly home includes solar panels, a graywater reuse system, tankless hot water, solar tubes, and rainwater...