01/04/2016 11:56 EST | Updated 01/04/2017 05:12 EST

A New Natural Barrier Against Influenza Virus


As 2016 begins, the celebrations of the holidays are put behind us and we begin to look forward to the remaining months of the winter. Along with the trepidation of returning to work as well as keeping those resolutions, another fear will soon grip Canadians. The flu is coming back. Based on the information from the Public Health Agency of Canada, the virus is slowly making its way across the country and establishing a hold on our collective lungs. Within a few weeks, the entire country will be awash in sniffles, coughs, and sick days.

For public health officials, the best route of protection is prevention and that means taking the flu vaccine. However, despite the proven record of the shot over the last decade, a number of issues have arisen to give people pause. In the last recorded year, only one-third of Canadians over the age of 12 decided to get vaccinated. This means over 60 per cent of the population may be left vulnerable to infection.

In absence of the vaccine, the only recourse is to increase diligence to hygiene and social distancing. This may work in many scenarios but not all such as intimate family moments, crowded environments, and the inadvertent and unexpected cough from a co-commuter. In these situations, the chance for a shared infectious droplet is high.

There is a known method to ensure infection is not transmitted: use a mask. Of course, surgical masks, while effective, may not be the best visually acceptable choice. Other options, such as scarves or towels can also help to keep your lungs safe while not drawing too much attention.

These barrier methods all deal with the outside of the body. But there may be a way to provide a barrier to influenza on the inside. The concept may seem complex but in reality it's rather easy to conceive thanks in part to the simple nature by which viruses like influenza infect.

Unlike bacteria, which can live on their own in any environment, viruses need to live and reproduce within a cell. This means it has to somehow find a way to gain access. Each of our cells is protected by a rather complex membrane that serves as a barrier to the outside. Viruses cannot break through this wall and have to somehow figure out they can be allowed entry.

The mechanism of influenza cellular invasion involves two viral protein known as hemagglutinin (also called HA or H as H1N1) and neuraminidase (NA or N). The NA protein clears the path of mucus and other molecular barriers allowing HA contact with the cell. Once this happens, the cell is tricked into allowing the virus entry so it can begin its infectious attack.

Finding a barrier to this process has involved an examination of a variety of chemical options. Some of the best come from natural sources. Familiar names such as pine and licorice as well as some rather odd names like jujube have all shown their ability to prevent influenza infection by providing a chemical block between the H protein and the cell. In each case, both studies in the lab, in mice and in some cases, in humans, all reveal the addition of a natural chemical barrier such as drops or a spray can help keep a person healthy.

The successes of these searches have led to investigations of other chemicals known to provide other beneficial effects to the human body. Last week, a team of Chinese researchers revealed their examinations into the influenza-blocking activity of the phytochemical quercetin. The results suggest this molecule, better known as an anti-inflammatory, may one day offer an entirely different benefit.

The work was relatively straightforward. In the lab, quercetin was added to cells prior to infection with influenza. After a few days, the results were compared with another group of infected cells not given the anti-inflammatory molecule. As expected, there was significantly less infection in those given the phytochemical.

But that part of the experiment wasn't the major finding. The researchers' main goal was to learn how the virus was stopped. Based on chemical analyses, the group learned quercetin blocked the HA protein. This meant the molecule didn't prevent the virus from clearing the mucus but instead, blocked virus entry. In practice, this meant adding quercetin to the vulnerable cells could help stop infection by keeping the virus on the outside.

For the authors, this study suggested quercetin may one day be a possible protective agent against influenza. To get there, the tests need to be run in animals and also in humans much like other proven natural barriers. Until then, quercetin can still be used to keep inflammation down and help keep your body in good shape to fight off any infectious invasions.


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