Viruses are feared for a reason – they hijack our cells, copy themselves using our host cell machinery, and then destroy the cells in a process called lysis. Basically, they’re the unwanted guests that trash the house before leaving. Not ideal for staying healthy… unless you’re a virus, of course. Then it’s party time. All viruses are bad for our health, right?
Wrong.
While around two hundred kinds of viruses are known to infect, sicken, or kill us, the emergence of SARS-CoV-2 has most recently discovered that this is only one part of the picture.
Viruses also keep us alive.
They form part of the body’s microbiome and safeguard our health. They can be harnessed to treat illness, deliver vaccines, and diagnose infections. Scientists use them as tools to better understand biology, diseases, and to help create new medicines. Parts of old viral DNA, which became part of our own DNA millions of years ago, actually help our bodies work – especially our nervous and reproductive systems.
Protovirus components likely even contributed to the emergence of life on Earth, and viruses continue to drive evolution today. They form a crucial part of the global ecosystem that allows us to survive.
Eugene Koonin (an expert on the genetics of evolution and viruses at the National Institute of Health’s National Centre for Biotechnology Information) says that “we can’t generalise viruses as being harmful because despite the devastating effects of viral diseases, the viruses that count most in our lives are crucial not in disease, but in health and in all aspects of life”
So what research and experiments support this?
While studying bacteria from sick patients, a microbiologist called Félix d’Hérelle noticed something strange: in people who recovered, something invisible under his microscope was killing the bacteria. He called these mysterious bacteria-destroyer’s bacteriophages – literally ‘bacteria eaters’ – Halloween costume idea?
D’Hérelle quickly realised these phage’s could help fight bacterial infections. In 1919, he tested this theory during a typhoid outbreak in chickens – and cured them. Feeling bold (and maybe a little reckless), he later wanted to treat a boy with dysentery (what the-). But first, he and his team drank the phage solution themselves to test it. When no one keeled over, they gave it to the boy – who made a full recovery.
Later, better microscopes revealed the truth: phage’s are viruses that infect bacteria and archaea but leave plants and animals alone.
So, thanks to pioneers like d’Hérelle, we now know viruses aren’t always bad – they can actually help us in medicine and research. Who knew something that eats bacteria could be our tiny, invisible hero?
Strangely, the idea of phage’s as treatments has never overcome initial scepticism. Outside of areas such as eastern Europe, the medical community discarded them when antibiotics emerged mid-century. Today, however, phage-based therapies are gaining a lot of attention.
That’s partly because phage’s kill bacteria in a different way from antibiotics, offering a potential lifeline as antibiotic resistance plays a role in the deaths of 5 million people each year worldwide. Phage’s also offer specific, specialised targeting since most phage’s evolve to infect one or a few strains of bacteria or archaea. Identifying the bacterium causing a patient’s illness and finding a phage that kills it could wipe out the troublemaker and leave beneficial bacteria unharmed.
In the past few years, doctors operating under compassionate use allowances have saved a small number of people from life-threatening bacterial infections that defied all other treatments. The number of phage therapy clinical trials is going upward. In 2021, the U.S. FDA and the National Institute of Allergy and Infectious Diseases awarded $2.5 million in grants to groups developing phage-based therapies.
So how do they do it (I can sense you asking). Well, scientists showed that phages can break up biofilms, stubborn webs of bacteria and extracellular matrix that immune cells and antibiotics have difficulty penetrating. Modifying the phage’s to deliver genes into bacteria to enhance the activity of antibiotics and adding enzymes from other phage’s that “chew up” biofilm matrices produced even better results. Going back to d’Hérelle, in 2019 several colleagues at Massachusetts General Hospital built an intestine organoid and showed how a phage they’d isolated from Shigella vanquished infection.
So, while your GCSE textbook or science worksheet states that all Viruses are bad or just highlights the harmful viruses that can infect our cells, remember that there are viruses in your body fighting infections at this very moment and killing these harmful bacteria in your body – without you even knowing.
I hope you learned something new, and I look forward to seeing you next week for a new question and a new answer.
