“Virus” is a word all too familiar to us during the past two years. Covid-19 is caused by a new virus called SARS-CoV-2 that seemed to come from nowhere in 2019. With breakneck speed scientists collaborating around the world analyzed the genetic code of the novel corona virus and created vaccines to improve our immunity to it. But less than a century ago, we knew next to nothing about viruses.
On this day in 1935 it was announced that a virus had been crystallized, providing a breakthrough into the study of a pathogen that up until that time had remained mysterious. A virus “crystal” consists of several thousand viruses and, because of its purity, is well suited for chemical studies.
Wendell Meredith Stanley crystallized tobacco mosaic virus (TMV) in 1935. For his work, he was awarded the Nobel Prize in Chemistry in 1946.
Dutch microbiologist Martinus Beijerinck was the first to recognize that viruses are reproducing entities that are different from other organisms. He was the first, in 1898, to call “virus” the infectious agent of the tobacco mosaic disease.
Fast forward to 1953 when a pandemic of poliomyelitis swept Canada. Polio is a disabling and life-threatening disease caused by the poliovirus. The virus spreads from person to person and can infect a person’s spinal cord, causing paralysis.
The virus mainly came in waves during the summer. On the Prairies, swimming pools were closed and children kept at home. I was one of the thousands of children hospitalized with polio. Fortunately my symptoms were mild. I only spent a month in hospital and have had no lasting effects. However, my roommate in university was partially crippled by polio and often wore a brace on her leg.
Immunizations were the great turning point in the battle against polio. In 1955, scientists Carlton E. Schwerdt and Fred L. Schaffer announce they had crystallized the polio virus which meant they could better determine the virus’ chemical and biological properties. The first vaccine against polio was introduced by an American, Dr. Jonas Salk, in 1955. The vaccine was developed in Canada with the help of Connaught Laboratories (then part of the University of Toronto).
Like an episode out of a TV drama, Salk first tested his experimental killed-virus vaccine on himself and his family in 1953, and a year later on 1.6 million children in Canada, Finland and the USA. The results were announced on April 12, 1955, and Salk’s inactivated polio vaccine (IPV). Although vaccine production was a private industry free for all in the US, but Canadian federal and provincial governments shared the full cost of the vaccine testing and production and distributed it free to children in grades 1 to 3, who were most susceptible to polio.
The Salk vaccine was given by injection, but in 1960 a vaccine that could be swallowed became available. Oral poliovirus vaccine (OPV) or Sabin vaccine was named for its inventor, American physician and microbiologist Albert Sabin. OPV contains live attenuated (weakened) virus and is given orally. I remember it as a red, fruit-flavoured liquid served in a little paper cup.
Polio is spread by person to person contact, likely through fecal matter. (Yuck). I believe I got the virus as Sunday School since it was the only place we went off the farm when I was four. Children are not reliable hand washers and the church lacked indoor plumbing. You don’t have to be Sherlock Holmes to figure out how I got sick.
Despite the ravages of polio, the most deadly virus in our lifetime has been Ebola which spreads through blood and body fluids. As many as 50 percent of those infected will die.
The most deadly pandemic during the past century was the so-called Spanish Flu. It was caused by the H1N1 virus in 1918 at the end of the First World War. Soldiers were traveling and spread the virus around the world as they returned from the battlefields of Europe. More people died from the H1N1 pandemic than from the war. With SARS-CoV-2, strict lockdown measures were put in place early in the pandemic, which limited the spread of the disease even within cities.
The current pandemic is also different in that Covid-19 mainly causes severe symptoms in people over 65 and those with underlying health conditions, whereas the 1918 influenza caused severe symptoms in young and healthy populations.
