Frog Killer Fungus In New Zealand

The Department of Conservation today announced survey work to determine the distribution of a frog killer disease in New Zealand.

DOC science manager Don Newman said the lethal chytrid (pronounced kitrid) fungus was previously unknown in New Zealand, and was thought to have contributed to the extinction of six frog species in Australia. Canterbury University’s Dr Bruce Waldman discovered the fungus in New Zealand late 1999.

“This fungus has killed over 90% of infected frogs in Australia. It damages the skin of frogs and either kills them by releasing toxins or by suffocating the frogs as they breathe through their skin. The impact of the fungus is probably enhanced by other environmental factors like habitat destruction, pollution, or even the thinning ozone layer and the linked increase in UV radiation.”

Frogs are considered an indicator of environmental health. Over the past ten years, amphibian populations have declined throughout the world, with frogs of Central America and Australia particularly hard hit.

“The fungus is only known in a Canterbury pond so far affecting the southern bell frog (Litoria raniformis) , an Australian species. However, it is important to warn people not to spread the fungus unwittingly, especially those who gather frogs for the local pet trade. I also encourage people who see sick or dying frogs to contact their local DOC office. This fungus may be present in other areas – we are investigating other areas and are being especially vigilant in areas where our endangered native frogs are found such as the Coromandel.”

Two people will be employed temporarily to determine how widespread the fungus is in New Zealand, focusing on Canterbury and Waikato initially. The Biosecurity Technical Forum, a group representing biosecurity agencies including DOC and the Ministry of Agriculture and Forestry (MAF), approved the survey. Any sick frogs discovered will be sent to New Zealand Wildlife Health Centre for testing by Dr Richard Norman.

New Zealand’s four native species are regarded as amongst the most primitive frogs living in the world today. All are considered threatened, one being endangered and another vulnerable following the International Union for Conservation of Nature’s categories.

“Quarantine and hygiene are of the utmost importance because people can spread the fungus, although it is unlikely that the fungus will infect people. Generally, frogs should not be handled and sick frogs should not be moved to new ponds. A sick frog is one that takes no evasive action when an attempt is made to catch it.”

Before the chytrid fungus was identified as a cause behind the skin infections of frogs in Australia and America, it was not known to cause disease in vertebrates. Chytrid fungi are related to the most primitive fungi.

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