Chytrid Fungus in the Pet Trade

As the trade of amphibians is highly unregulated, disease testing of amphibians traveling between countries and states is next to none. Many amphibians that travel often are carries of the chytrid fungus, which is greatly responsible for the amphibian declines around the world. Approximately 300 species have been detected with chytrid and it is now present in nearly 40 countries. In 2011, a study found that in many pet shops and pet expos nearly 3% of the captive amphibians tested positive for the presence of chytrid, and 13.6% of the collections yielded at least one positive result.
Humans ship millions of amphibians around the world each year. When an infected frog arrives in a new location, its disease can spread to native populations if (1) it escapes captivity, (2) it is intentionally set free, or (3) water from its holding tank is released into the environment. Native amphibian populations generally have no evolved defenses against the new pathogen, and an epidemic that results in population decline or extinction can occur. The largely unregulated pet and food trades are the two most common sources of disease introduction into naïve amphibian populations. For instance, the skin disease chytridiomycosis has been detected in Mexican axolotls in Australian pet shops, and in American bullfrogs being farmed for international trade in Uruguay. Infected frogs are also unintentionally exported internationally via the zoo trade and laboratory animal trade.
In 2003, Australia enacted what are perhaps the world's strictest regulations on the importation of non-native amphibians, this being due to chytridiomycosis having driven at least seven of Australia's frog species to complete extinction after it was introduced into the country in the late 1970's. Amphibian importation is now allowed only for zoological and laboratory usage, and must be accompanied by certificates demonstrating that stringent disease control measures (including quarantine) have taken place.
Japan banned both the sale and import of American Bullfrogs (Lithobates catesbeianus) in 2006, and South Korea banned their importation circa 2007, both countries in part due to the consistently high chytrid infection levels found in this species, which sees heavy trade and transport.