GOOD news at last for frogs and other amphibians: we might start spraying them with dead fungus. It might sound weird, but the idea is to vaccinate them against an infectious killer fungus. Other fungal diseases could potentially be treated in the same way.
Since it emerged in the 1980s, has globally and contributed to the decline of dozens of species. This chytrid fungus cripples the immune systems and makes the amphibians鈥� skin grow too thick to absorb water, causing dehydration and heart failure.
聯The chytrid fungus kills frogs and other amphibians by making their skin too thick to absorb water聰
Advertisement
Chytrids can be fought with fungicides, but these kill other organisms too and are only a short-term measure. A vaccine should have a lasting and specific effect on the amphibians.
of the University of South Florida in Tampa and his colleagues froze the fungus to kill it, then put dead fungal cells on the skin of . Frogs were treated with the cells one to four times. Later, Rohr infected them with live fungus. Frogs that had more rounds of vaccination had fewer surviving fungus cells per gram of tissue (). 鈥淔ungal counts went down from around 40,000 to 8000 fungal cells per gram,鈥� says Rohr.
Rohr hopes to vaccinate wild amphibians by spraying the dead fungus into their habitats. He wants to try it within two years, probably in isolated amphibian colonies in California, one of the worst affected areas in the US. 鈥淚f the colonies are small and isolated, it makes it easier for us to recapture and test the vaccinated animals for immunity,鈥� he says.
That might not work, says of San Diego Zoo in California. 鈥淚t is easy to expose lab frogs to a sufficient quantity of dead fungus to get a response,鈥� says Pessier. 鈥淏ut in a wild setting, it will be a huge challenge to expose frogs to enough of the vaccine, for a long enough period to be effective, before the material is washed away or degraded.鈥� He says it is also unclear how rarer species like respond to the vaccine.
Instead, it might be better to vaccinate captive amphibians and then release them into the wild. 鈥淚t could facilitate reintroduction of captive-bred amphibians to locations in the wild where the fungus persists,鈥� says Rohr鈥檚 colleague . At the moment such reintroductions are risky, because the frogs are vulnerable to the chytrid fungus.
If the vaccination works for amphibians, a similar approach might help fight fungal diseases in other species, such as white nose syndrome that is killing bats in the US. 鈥淚t could possibly be used as a management tool for many of these diseases,鈥� says Rohr. 鈥淚t holds promise against white nose syndrome in bats and lots of other diseases, such as those affecting snakes and bees.鈥�
It does look promising, says white nose syndrome expert of the US National Wildlife Health Center in Madison, Wisconsin. 鈥淢ass-delivered anti-fungal vaccines could provide long-lasting protection to populations of impacted wildlife.鈥� Other proposed treatments don鈥檛 do that.
This article appeared in print under the headline 鈥淰accine could stop frog-killing fungus鈥�
