Kissing a frog may keep flu at bay


Staff Reporter

Kissing a frog could just be the way to kick flu, although not literally just yet. Although more research is still to be carried out to arrive at a definitive conclusion, findings from a new scientific study suggest that that mucus from the skin of certain frogs can be harnessed to obliterate flu viruses.
Scientists from Emory University have found that some frog mucus contains antimicrobial peptides, which are immune system molecules that can neutralise bacteria, viruses, and fungi.
The particular frog in question is a species native to southern India and is called Hydrophylax bahuvistara. In the film of secretions that protects this Indian frog’s skin from deadly pathogens, scientists have identified a string of amino acids that completely destroys a wide swath of influenza A viruses while doing no harm to healthy human red blood cells.
However, so far the flu-killing power of such peptides has been demonstrated only under a microscope and in lab mice. More research is needed to determine just how effective a peptide can be in helping humans beat the flu, froggy style.
“We have identified a potential new treatment for H1N1 human influenza virus, which is a peptide that comes from the skin of a frog from southern India,” said Joshy Jacob, an associate professor in the Emory University School of Medicine’s microbiology and immunology department, who led the study.
The peptide, named urumin, specifically targets H1 flu viruses, according to the study, published Tuesday in the journal Immunity. “This peptide works by directly killing the virus, and it is specific for all influenza viruses that have a H1 type of hemagglutinin,” Jacob said.
Hemagglutinin is a spike-shaped protein found on the surface of flu viruses. For the viruses to make you sick, the spikes of hemagglutinin attach to your cells to infect them.
Influenza A viruses – one of four types, two of which routinely spread in people – are categorized into subtypes H1, H2, H3, H5, and H7 based on their hemagglutinin. ‘It makes the virus particle fall apart.’
For the study, skin secretions were collected from 15 frogs, of the species Hydrophylax bahuvistara, which are about the size of a tennis ball and brightly coloured. Peptides were then gathered from their secretions.
The researchers observed how the peptides interacted with influenza viruses under a microscope and in mice. “In this paper we screened 32 peptides, and the surprise was that four out of 32 had activity against the virus,” Jacob said.
“Out of the four, we found one of them (urumin) was non-toxic to human cells,” he said. “So, we tested it against viruses that came from the 1930s until the current ones, and it kills all of the H1’s. It doesn’t touch H3. It’s very, very specific.”
Currently, flu subtypes H1 and H3 are circulating among humans worldwide, including across North America, Europe, and South Asia, according to the World Health Organisation.
The researchers aren’t quite sure why urumin only targets H1 viruses, but Jacob said that H1 viruses might be anatomically similar to an amphibian pathogen that the frog mucus is intended to destroy. If there is a similarity, it may explain why H1 viruses are vulnerable to urumin’s wrath.
“The frog makes this peptide for its own survival. It never gets influenza,” Jacob said, adding that the peptide fights the flu virus by destroying an important part of the hemagglutinin.
The urumin peptide could be a novel treatment since it targets the hemagglutinin, unlike current drugs on the market which target other parts of the virus, resulting in less impact, Jacob said.
“It just blows it up. It makes the virus particle fall apart,” he said.

It was first discovered that frogs had a special way of warding off bacteria and other pathogens in ancient Russia, when live Russian Brown frogs were dropped into milk to keep the milk from going sour, according to the American Chemical Society.
“The milk stayed good, just like you refrigerated it,” Jacob said about the age-old Russian practice.
“In 2012, scientists took that particular frog and wanted to know why is it, why do these frogs keep milk fresh? It turned out that when you shock a frog or when you stimulate them or stress them, they secrete these short peptides into their surroundings,” he said. “A majority of the peptides were antibacterial and some of them kill the things that make milk go bad.”
– Compiled from CNN & LA Times.


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