Will faecal transplants and tea cure flu?

11 August 2017
Posted by Alexandra Ashcroft.

A certain species of bacteria breaks down compounds, commonly found in black tea, to create a molecule that protects their host from the flu virus, scientists discover.
The influenza virus, which causes the flu, is normally associated with coughing and runny noses but actually kills around 600 people in the UK, each year.

In fact, “when different people are exposed to the same strain of flu, there’s a huge variety [of] responses: some people develop a mild upper respiratory infection, [the] sniffles, some people become hospitalised and some people even die”, explains professor Thaddeus Stappenbeck, who led the study, published last week in Science.

Because the flu can be so dangerous, each year societies inoculate vulnerable individuals against it.  This teaches their immune systems to recognise the virus and protects them from it.

Inoculations are an excellent example of public health done right. They have saved numerous lives. But, each year, it’s a race against time for scientists to develop a new jab in time for flu season. Not to mention, this process is expensive. There is thus a real need for a flu treatment that works every year.

Stappenbeck’s work might one day deliver such a medication, in a very unusual form: drinking tea and adding a certain species of bacteria back to your gut, perhaps via “a pill that would have spores of these particular bacteria.”

Stappenbeck and his colleagues discovered that a certain species of bacteria, called Clostridium orbiscindens, degrades compounds present in food, flavonoids, to create molecules that ”potentially can protect you against having a serious outcome of influenza”.

Stappenbeck had previously been working on a type of certain part of the immune system called interferon signalling, which is “known to be generated in response to different infections, most notably viral infections”. He found that mice with elevated interferon signalling are protected against the flu.

This discovery, plus the knowledge that “reduced, or absent, microbes leads to increased sensitivity to influenza”, lead to the proposal that perhaps the bacteria work through interferon signaling to protect against the flu. Stappenbeck’s team thus “screen[ed] for molecules that can stimulate ...interferon [signalling]”. Their top candidate was called desaminotyrosine.

When they gave this compound to mice infected with the influenza virus, they found almost 100% of the mice survived the infection, compared to just  50% of untreated mice. It didn't actually get rid of the virus, but rather stopped the symptons.

Stappenbeck also found Clostridium orbiscindens, found in human and mouse intestines, can make desaminotyrosine from “molecules present in food called flavonoids…[and that] the food that probably has the highest concentration of flavonoids is black tea”.

Stappenbeck only identified this one species that can make desaminotyrosine but says there “could very well be other microbes that exist that could perform the same function”.

But he also cautions that “there are interesting interactions between microbes and it’s very well possible that there are other factors that could potentiate the effects of desaminotyrosine or other factors that could diminish it”.

One of Stappenebck’s other goals is to work how many many people actually have Clostridium orbiscindens living in their intestines. Stappenbeck’s work has great potential as an alternative treatment for flu but in order for it to work you need both the flavonoids and the microbe that can break them down.

He says “it’s a combination of what’s in your diet plus having a particular microbe”. People lacking the bacteria would have to get them into their guts. Fortunately Stappenbeck believes the gruesome fecal transplants, used to treat other diseases, won’t be necessary to treat the flu.

Because we “know what the specific microbes are”...and that “they can be delivered as spores”, we could probably just get away taking with a pill of bacteria and drinking tea.

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