Herps in the news! Humans are contributors to the spread of the amphibian disease Batrachochytrium dendrobatidis by Alissa Carissimi

A sign in Bay area Chinatown stating that release of American bullfrogs is illegal. 

    As a graduate student at the University of Memphis, I am currently studying the lethal fungal pathogen Batrachochytrium dendrobatidis in amphibians so when I came across the following article in the New York Times, I realized that many people may not realize how much we contribute to the spread of amphibian and reptile diseases. This article reads much like a short story and translates the scientific information into layman's terms. The author, John Upton, takes a closer look into the amphibian trade that takes place in Chinatown of the Bay area in San Francisco, CA and how its residents and business owners contribute to the spread of Bd in local ecosystems. I'd like to discuss this New York Times article "Despite Deadly Fungus, Frog Imports Continue." published in April 2012 in hopes that those who read this blog may reconsider purchasing amphibians that have been imported. 

A common occurrence when the American bullfrog is released into non-native habitats. It quickly eliminates the competition for resources by killing off native competitors.

   In Chinese culture, the frog is considered to be a delicacy and a primary protein source for many people. Upton shows readers first hand that many frogs such as the American bullfrog ((Lithobates catesbeiana) are such a delicacy for Chinese people living in the United States. "A clerk serving Cantonese-speaking customers at a cluttered market in San Francisco’s Chinatown reached into a tub of American bullfrogs. She drew a one-pound frog from the top of the pile. She whacked its head, sliced its neck and placed its body in a plastic grocery bag." Clearly, the employee of this market do not see these frogs as anything other than a food source and it is alarming to say the least. Upton cautions readers that in addition to inhumane practice, the distribution of the American bullfrog in California has created ecological disasters because it is an invasive species. An invasive species are defined as those that are non-native (or alien) to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health (USDA: National Invasive Species Information Center). Upton elaborates this point by explaining how American bullfrogs are released into the wild by humans and once they've established an area their size enables them to eat native amphibian tadpoles, larvae and even ducklings! However, markets in Chinatown are not allowed to sell live bullfrogs and Upton makes sure to inform readers that those that are released into the wild are most likely from pet stores which can sell live bullfrogs. He also writes that this may be the result of Buddhist ceremonies but does not provide information to support the claim so I would investigate further before supporting his statement. In my opinion however, Upton does a pretty good job at backing up his claim that we are major contributors to the spread of Bd.

American bullfrogs are one of only a few species that are virtually asymptomatic when they become infected by Bd while nearly all other species die as a result of infection due to electrolyte depletion, osmotic imbalance and eventual cardiac arrest (Garner et al.,2006). Upton provides a basic overview of the disease but an effective one that enables readers of all backgrounds to understand the significance of Bd impact on amphibian communities and how humans are essentially helping Bd infect new hosts. "A study of 493 fresh-bought frogs from San Francisco, Los Angeles and New York found that 62 percent were infected with the chytrid fungus." I think that these statistics speak for themselves and I was shocked to learn that the percentage of infected individuals was so high despite my research in this field. Upton further illustrates the havoc Bd creates by speaking with some of the best researchers in the Bd realm such as Dr. Vance Vrendenburg who has published dozens of papers about this disease. I really enjoyed reading this article primarily because it educates the public about not only disease and invasive species but how these factors will lead to extinction of many of our beloved amphibian species if we continue to purchase and release amphibians that are non-native. In my opinion, if there was to be anything that Upton and amphibian researchers alike would want readers to learn form this article, it is that Bd is responsible for the loss of frogs worldwide and it is our responsibility to ensure that we are doing everything in our power to prevent transmission of this disease. Indeed, it is extremely important to inform the public more so than anyone about the potential risks involved with any disease regardless of its host because the everyday person who is oblivious is most likely practicing unsafe and risky behaviors that affect the health of people and animals alike.

References:

1. John, Upton. "Despite Deadly Fungus, Frog Imports Continue." New York Times 8 April 2012: A23A.

2. USDA: National Invasive Species Information Center. What is an Invasive species? http://www.invasivespeciesinfo.gov/whatis.shtml

3. Garner Trenton W.J, Perkins Matthew W, Govindarajulu Purnima, Seglie Daniele, Walker Susan, Cunningham Andrew A, and Fisher Matthew C.The emerging amphibian pathogen Batrachochytrium dendrobatidis globally infects introduced populations of the North American bullfrog, Rana catesbeiana. Biol Lett. 2006 September 22; 2(3): 455–459.