Professor Reid Harris Explores Probiotic Benefits for Amphibians and Humans

Since he was a kid, Dr. Reid Harris loved learning about frogs and salamanders.  While an undergraduate at Duke University, Harris realized that he could have the best of both worlds: study amphibians for the rest of his life and share his enthusiasm for biology by teaching college classes and directing research projects.  His undergraduate mentor, Dr. Henry Wilbur, was influential in this decision and Harris later completed is doctorate under Dr. Wilbur’s tutelage. 

Harris’s research at JMU focuses on disease mitigation through the use of topical probiotics.  The bacterial cells that live on, and in, our bodies outnumber our own cells by a ten to one ratio. Although some bacteria are harmful to humans, most species are not harmful and can even be beneficial.  Probiotic therapy is the use of these beneficial bacteria to achieve a positive health outcome.  Probiotics, such as the beneficial bacteria found in yogurt, has been shown to prevent and treat several diseases of the intestinal tract.  Over the years, Harris feels fortunate to have worked with a wonderful group of postdoctoral associates, master’s students and undergraduate students on furthering probiotic research.

Recently, Harris has been researching Bd, a lethal skin fungus, which has decimated amphibian populations worldwide. In the mountains of Panamá, almost half of amphibian populations have decreased, or become extinct altogether, because of Bd. Bd appears to be spread by humans through various methods such as the pet trade. Amphibians are valuable to our ecosystem through insect control and production of secretions that have been models for valuable human pharmaceuticals.  Recently, it was discovered by a scientist at Vanderbilt University that an amphibian secretion can inhibit HIV.

In a number of laboratory experiments, Harris and his lab were able to show that probiotic additions of antifungal bacteria can protect amphibians from the harmful effects of Bd.  In the lab, they discovered that amphibian skins have protective bacteria that can inhibit and kill the lethal pathogen, Bd.  With collaboration from his team, Harris was able to show that the probiotic therapy can also work outside the lab in field conditions.  Members of his laboratory are working on how to deliver these probiotics to large numbers of amphibians in the field.  These methods can involve adding the probiotic to ponds where amphibians congregate to breed.  Harris and his team recognized that they would need use locally-occurring bacteria so that nothing exotic or invasive is added to the ecosystem.

One of the largest amphibian ecosystems exists on the island of Madagascar which has about 500 species of frogs. Currently Bd is absent from the island, but scientist worry it may arrive at any time given the rate at which it has spread around the world.  Harris has been working with former student, Molly Bletz, on a project that identifies antifungal probiotics in Madagascar.  Bletz plans to pursue this project for her doctoral research.

Besides protecting frogs from Bd, probiotics can be used to protect other endangered species that are being bred in captivity before they are released into the wild.  For example, hellbender salamanders are a threatened species in Ohio (among other states) and are being raised in captive breeding facilities.  Harris and former student, Andy Loudon, are working to find effective probiotics for the salamander species to ease their transition from zoo colonies into the field.  Another former student, Matt Becker, now a doctoral student at Virginia Tech, is working on finding probiotics to allow the Panamanian golden frog to be repatriated to nature.  This species is culturally important in Panamá, but is extinct in nature.  Fortunately, this species is being successfully raised in a number of zoos around the world. 

The Harris lab has also connected human fungal diseases, such as athletes’ foot disease, with the amphibian bacteria. They found that the bacteria, also found on human skin, can inhibit the fungus that causes athletes’ foot. Harris and his colleague, Dr. Kevin Minbiole, of Villanova University and the James Madison Institute, have a patent on this potential skin probiotic. Athletes’ foot disease can be difficult to treat with drugs, so their hope is that a skin probiotic will help cure this disease.

In addition to his work on probiotics, Harris’s lab is studying the basic question of amphibians’ microbial ecology, such as what is the relationship of microbial community structure and protection from disease.  This work is part of a collaboration with Virginia Tech and Villanova and is funded by the National Science Foundation’s Dimensions of Biodiversity program.

Harris has been named a Madison Scholar in the College of Science and Mathematics and received a Provost’s Award for Excellence in Research.  He was recently elected a fellow of the American Association for the Advancement of Science for his research in amphibian microbial ecology.