Coronavirus gives the virus family a bad name

Most viruses are benign and some are even lifesaving. Only a few cause panic and fear.

Bacteriophage, Image from Bacteriophage.news

We are literally immersed in viruses. A UBC professor has discovered that billions of them rain down on us daily. Curtis Suttle, co-author of the study found their source. He was initially puzzled as to why the same viruses are found everywhere on Earth.

“We found the same viruses pretty much everywhere in the planet,” Suttle told CBC radio’s Quirks & Quarks. “We would find the same viruses in a meltwater pond in the Arctic Ocean, or in the Gulf of Mexico, or in a lake in Germany. It was puzzling to use because we wouldn’t expect the same host organisms to exist in all those different environments (December 28, 2018).”

He found that the viruses are swept up from deserts and oceans and carried aloft to altitudes of 3,000 metres where they cross continents and rain down upon the earth in a microbial deluge, largely unseen and unnoticed by humans.

Suttle and his colleagues found that more than 800 million viruses per square metre are deposited into the atmosphere every day. Before his study was released, it was thought that this area of the atmosphere was pristine.

If you like to swim in the ocean, as I do, you might find the following a little unsettling. The average concentration of viruses in seawater is billions in every millilitre of water. “So for every time you go swimming, just for the water you take into your mouth, you swallow more viruses than there are people in North America,” said Suttle.

But be assured that the billions of viruses are doing good work there. They kill 40 per cent of the oceans bacteria daily. Yes, almost one-half of the bacteria are eliminated which controls their population and keeps the Earth’s oxygen from being depleted.

And the viruses you breathe in kill some of the bacteria that you also inhale.

This ability of viruses to kill bacteria is a lifesaver for people who have become resistant to antibiotics. The viruses are called bacteriophages, or phages for short.

The number of patients who are multidrug-resistant (MDR) is growing as infections become resistant to antibiotics. MDR infections are rapidly growing into public health nightmare. At least 700,000 people die annually and the United Nations predict that the numbers could rise to 10 million by 2050 (Scientific American, November, 2019).

Where antibiotics also kill useful bacteria in a shotgun approach, phages target specific bacteria. They attach to the cell wall of the bacteria and insert their genetic material into the cell through a syringe-like appendage. The phage then highjacks the bacteria’s reproductive machinery and making multiple copies of itself, ripping the bacteria apart.

The bacteria-fighting properties of phages have been known since 1910 where they reportedly reduced wartime mortality from gangrene. But after antibiotics became the drug of choice, investigation of phages waned.

Don’t go to your doctor looking for phage medications. Lack of research has limited their use but as the number of MDR cases rises, research will accelerate.

So, don’t tar all viruses with the Coronavirus brush. Their life-saving applications will almost certainly grow, saving more lives than they kill.

Your microbiome and cancer

Lab studies indicate that the composition of your microbiome can help fight cancer. Your microbiome is the unique set of bacteria you carry around with you, or it might be more accurately said that they carry you around since they outnumber body cells ten to one.

Checkpoint inhibitors prevent T-cells from recognizing cancer as friend.

Checkpoint inhibitors prevent T-cells from recognizing cancer as friend.

Your microbiome can affect immune response, which in turn can fight cancer. Unfortunately, your immune system doesn’t always recognize cancer as a threat. Solid tumors are especially hard to target. Skin and lung cancers form solid masses that are hard to penetrate compared to liquid tumors in the blood.

Cancer cells hide by fooling immune cells into thinking they are not foreign at all. To determine friend or foe, immune cells check for a protein. If they find it on cancer cells, they appear as friends.

One innovative cancer treatment involves an immunotherapy drug called checkpoint inhibitors which do just what the name suggests –they block the checkpoint that looks for friend or foe. Seeing no friend because they are blocked, immune cells mount a defense.

This is where the microbiome comes in. Gut bacteria affect our immune system’s inflammatory response. Scientists at the University of Chicago found that mice responded to cancer invasion in varying degrees according to the type of bacteria in their guts (Scientific American, April, 2016).

Mice that were fed a particular strain of bacteria were able to fight skin cancer better than those who weren’t. When poop from the cancer-fighters was transferred to others, tumor growth slowed.

Remarkably, when checkpoint inhibitors were given to both the mice with the particular bacteria and those with the fecal transplant, tumors disappeared completely in the former and was reduced in the other. Then, when the mice with the fecal transplant were also given the bacteria, they were cured completely.

French scientists had similar results in which both the checkpoint inhibitor and a different bacteria were given. Next, the scientists gave antibiotics to the mice which killed bacteria, including the beneficial ones. The conclusion is obvious: doctors need to be cautious in prescribing antibiotics to cancer patients.

Not any bacteria will do. The Chicago team used either Bifidobacterium longum or Bifidobacterium breve. The French used Bacteroides. Yogurt contains Bifidobacterium lactis or Bifidobacterium bifidum remains untested.

Fine-tuning the immune system is a tricky business. The wrong kind of bacteria could cause the immune system to become too active and attack normal tissue. Autoimmune diseases include type-1 diabetes, inflammatory bowel disease, psoriasis, and rheumatoid arthritis. The effect of general bacteria on fine-tuning the immune system still needs to be investigated.

“Obviously we need to categorize the bacteria in the human microbiome and their potential antitumor effects more completely before we can recommend any treatments in people,” cautions the Chicago team.