Scientists have discovered an unlikely weapon in the fight against the influenza virus: a special chemical found in the mucus of South Indian frogs.

According to a study published in the journal "Immunity," skin slime from Hydrophylax bahuvistara - a species of fungoid frog - has the capacity to kill some strains of the flu thanks to a molecule known as "urumin," fittingly named after a traditional Indian whip-like sword.

Researchers were able to test synthesized versions of the compound on mice, which successfully managed to destroy a number of flu strains (including the much-maligned H1N1 virus, also known as swine flu, which has previously proved resistant to other drug treatments).

Frogs are immune to the influenza virus - however, they are vulnerable to bacterial and fungal infections among other diseases. This knowledge gave the researchers a reason to believe that their peptide bonds could contain anti-viral elements.

"I was almost knocked off my chair," said lead author Joshy Jacob from the Emory University School of Medicine.

"In the beginning, I thought that when you do drug discovery, you have to go through thousands of drug candidates - even a million - before you get one or two hits. And here we did 32 peptides, and we had four hits."

The green-eyed tree frog has been found to have anti-viral peptides on its skin which could help treat the HIV virus in humans

Powerful medicine

Despite the promising findings, it will take some time before effective medicine becomes available. The "urumin" molecule does not survive long in the human body, meaning researchers will need to find a way to make it more stable before it can be used as a treatment option.

Luckily, scientists are confident they will eventually be able to chemically synthesize the compound for use in humans - meaning frogs are at least safe from being harvested in large quantities for medical purposes.

But this week's discovery does provide a glimpse into future possibilities of deriving similar compounds from other frog species that may be effective against other difficult-to-treat viruses, such as dengue fever and Zika.

A study published in the Journal of Virology in 2005 also found that chemicals isolated from the skin of certain frogs, such as the Australasian green-eyed tree frog (Litoria serrata) have the potential to inhibit HIV infection.

The Panamanian golden frog is one of many critically endangered frog species and may already be extinct in the wild

Protecting nature's pharmacy

The present breakthrough therefore offers an important incentive to protect threatened frog species, which may hold the key to curing some of our most dangerous viruses and preventing global pandemics like that in 2009.

According to the International Union for Conservation of Nature (IUCN) Red List, more than 41 percent percent of amphibians are currently under threat - more than mammals (25 percent) and birds (13 percent) combined. This includes 466 critically endangered frog species.

With numbers on a downward trajectory, scientists may be racing against the clock to isolate powerful disease-fighting compounds which are waiting to be discovered.

Since the 1980s, 120 frog species are believed to have become extinct. Habitat destruction, climate change, hunting and disease are the main culprits.

Yet at the same time, scientists are still coming across more undiscovered species; last year a new species of fungoid frog was found in peninsular India, and only last month two more species were discovered deep in the Amazon Rainforest.

Organizations like the Amphibian Survival Alliance are working to protect remaining frog species however - hoping to ensure the future survival of nature's pharmacy.

Frogs: amphibians under threat Once abundant, now endangered The critically endangered red-eyed stream frog, or Duellmanohyla uranochroa, has become a symbol for the global decline of amphibians. The nocturnal frog was once common in Costa Rica and Panama, but has suffered severe population declines due to habitat loss and fungal disease. An estimated 165 amphibian species have died out in recent years.

Frogs: amphibians under threat Why are they dying? The chytrid fungus is a major killer of amphibians worldwide. Chytridiomycosis disease destroys amphibians' delicate skin, which they also use to breathe through. It is believed to have come from the African clawed frog, which was used for human pregnancy testing throughout the world in the 1950s. The fungus spread and devastated many species, including these harlequin toads of the genus Atelopus.

Frogs: amphibians under threat Gliding into uncertainty Gliding frogs, like this one in Panama, are known for their spectacular leaps through rainforest canopies. But their territory is being threatened by logging - habitat destruction, such as deforestation and draining wetlands, is endangering the world’s amphibians. Climate change and the overuse of pesticides are other factors that scientists agree are making it harder for many species to survive.

Frogs: amphibians under threat Toads as canaries Amphibians are thought to be good indicators of how healthy the planet is. Because they absorb substances from the water and air during their lifecycle, they are more sensitive to the environment than most other animals. They have thus been described as "canaries in the coalmine," meaning they can provide early warnings of a deteriorating environment.

Frogs: amphibians under threat Humans need frogs Frogs, toads, salamanders, newts and caecilians - they all play a vital role in the food web. They eat insects and are in turn eaten by snakes, birds, and even humans. In medical research, some amphibians have been found to produce chemicals with the potential to cure human diseases. The frog pictured here secretes poison that native peoples have long applied to darts.

Frogs: amphibians under threat New species While many amphibian populations are endangered or extinct, new species are still being discovered. Last year, this bright "yellow dyer" frog, which colors your fingers yellow when you touch it, was discovered in the mountains of western Panama by Germany-based biologist Andreas Hertz. Its scientific name is Diasporus citrinobapheus.

Frogs: amphibians under threat Amphibian Ark Scientists specializing in amphibians and reptiles are called herpetologists - PhD student Andreas Hertz is one herpetologist on a mission to document rare amphibians in Latin America. Since 2007, a global project called "Amphibian Ark" has been underway, in which species are collected from the wild and put in quarantine before the deadly chytrid fungus can reach them.

Frogs: amphibians under threat Rediscovered in Israel The Hula painted frog was thought to be extinct for the past six decades - until one was found hopping across a road in northern Israel in 2011. Since then, more have been discovered, and there are believed to be up to 200 living in the Hula Valley. As an organism that has kept the same form over millions of years, it's considered a "living fossil."

Frogs: amphibians under threat Diverse and fascinating A victim of the pet trade and tourism, the strawberry poison dart frog is still classified as a species of "least concern" on the IUCN Red List. This tiny frog measures about 2.5 centimeters and is found in Costa Rica, Nicaragua, Panama and Puerto Rico. The venom from these frogs is less harmful to humans than that of other poison dart frogs, but can still cause discomfort.

Frogs: amphibians under threat Lungless amphibians The Bornean flat-headed frog (Barbourula kalimantanensis) is among the frog and salamander species with no lungs at all - they breathe exclusively through their skin. It lives in cold, fast-flowing rainforest streams on the island of Borneo in Indonesia. Listed as endangered, this very rare frog's environment is under threat from pollution and the toxic byproducts of illegal gold mining. Author: Samantha Early



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