Sick Salamanders… Chytrid fungus’ Next Victim

A fire salamander showing signs of fungal infection through skin lesions. A study suggests that the fungus, called Batrachochytrium salamandrivorans, may have reached Europe through the pet trade from Asia. Credit Frank Pasmans/Ghent University

A fire salamander showing signs of fungal infection through skin lesions. A study suggests that the fungus, called Batrachochytrium salamandrivorans, may have reached Europe through the pet trade from Asia. Credit Frank Pasmans/Ghent University

 

The human race is a global species that has adapted to live almost everywhere on earth. The rest of the living world has not quite caught up, which means most species have geographically evolved to combat the daily changes they face in their own home environment. Some species home ranges are quite large, such as the warbler and the monarch butterfly who migrate more than a 1000km to avoid our Canadian winters! Other species, like our amphibian friends, don’t have this luxury. For example the Ontario leopard frog has one of the largest home ranges for amphibians at 600 square meters, and on the smaller side the red back salamander’s home range is only 2-3 square meters! When home ranges are small, interactions to challenges like a new invasive predator or disease are rare. When a change is introduced, like a disease for instance, it is more likely to have devastating effects on the population, since immunity is something that develops over long periods of time.

 

The exotic pet trade is creating a big problem for our amphibian friends through disease transmission. Release and escaped pets introduce disease and fungi to that our susceptible native frog and salamander populations. Transmission can happen through simply rinsing a contaminated aquarium outside, or not washing servicing equipment when moving from area to another. Given the geographical distance between these exotic and native species, foreign bodies should have never been able to interact in the first place, and as a result our native amphibians are left pretty much defenceless as they have not developed immunity to these new challenges.

 
Chytrid fungus is a now infamous fungus that has caused the extinction of hundreds of frog and toad species around the world, and researchers are saying our salamanders will be next.
An emerging infection similar to Chytrid fungus is killing salamanders in Europe and could easily spread to the United States with disastrous effects, scientists reported Thursday.
Writing in the journal Science, an international team of 27 researchers blamed the spread of the disease on “globalization and a lack of biosecurity” and said the importation of the fire-bellied newt in the pet trade with Asia was the likely cause.

 
The lead researcher, An Martel of Ghent University in Belgium, said in an interview that both Europe and the United States need to start implementing tougher screening measures for amphibians in the pet trade: “When animals are traded, they should be screened,” Dr. Martel said, “It should involve the world.”

 
Other scientists agreed. “We need to pay attention to this paper,” said Vance T. Vredenburg of San Francisco State University, one of the scientists who has sounded the alarm about the extinction of hundreds of frog and toad species worldwide over the last four decades: “We need to think about biosecurity not just in terms of humans and food that we eat and crops that we grow…We need to think about functioning ecosystems.”

 
In the frog disappearances, the culprit, a fungus called Batrachochytrium dendrobatidis (Chytrid fungus), was not identified until decades after the extinctions had begun. Where it originated is still not known.

 
The spread of this fungus, according to Dr. Vredenburg, represents “the worst case in recorded history of a single pathogen affecting vertebrates,” causing an “extinction rate 40,000 times higher than in the last 350 million years for amphibians.”

 
The fungus killing salamanders and newts, Batrachochytrium salamandrivorans, is in the same genus, and it also kills animals by infecting the skin. But this time, Dr. Vredenburg has a more optimistic outlook: “We found it early enough to have a chance. The Titanic knows there’s an iceberg out there.”

 
The United States, as of yet untouched by the infection, has the greatest biodiversity of salamanders in the world, and many of its species are already threatened or endangered.
The animals are seldom noticed but are an integral part of forest and aquatic ecosystems, as predators and prey.

 
A recent study suggested that their decline could affect climate change because the proliferation of some of the creatures they eat could cause a greater release of carbon into the atmosphere.
James Collins, at Arizona State University, who has studied the spread of fungal disease in frogs, argues that further study was needed to prove that the pet trade was the sole culprit in the disease’s spread. He suggests that there is a possibility that the fungus was wind-borne, or spread by migrating birds.

 
However, Dr. Collins acknowledges that the fungus and the lack of screening in the shipping of live animals still poses a major threat to salamanders in the United States and Europe. Disease screening is still limited to threats to agriculture, he said, and excludes animals in the pet and aquarium trades.

 
When a virus such as Ebola emerges, it gives impetus for international and federal agencies like the World Health Organization or the Centers for Disease Control and Prevention to take action. “Something like that is needed,” he said.

 
So what can we do to help?
– Source your exotic pet from a local reputable breeder and avoid buying animals that are shipped from overseas.
– Understand that your exotic pet may carry diseases even if it’s not sick. Exotic pest should visit a veterinarian, just like our other pets! Never release your exotic pet into the wild.
– Sanitize any husbandry equipment (hoses, scrub brushes, aquariums, habitat structures) with a mixture of bleach and water before selling or loaning the equipment.

 

This article was adapted from the original article by James Gorman, The New York Times, published Oct 30 2014

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