By LEX SCHRAG
Toronto's research program in the battle against polio is faced with three routes to its objective. Early this month, Dr. A. J. Rhodes, University of Toronto professor of virus infections, attended the Copenhagen conference on polio which was jointly sponsored by Danish) and U.S. associations. From the conference, he brought back to Toronto information which tended. to support the theory on which Toronto researchers are working.
Dr. Gilbert Dalldorf of the New York State Department of Health reported to the convention on the Coxsackie virus-a virus named for the New York town where it was first isolated in 1947. While Dr. Dalldorf had been working on Coxsackie virus which produces most of the symptoms of poliomyelitis, but which does not paralyze Canadian workers had noted a similar ailment in Toronto,
Later, Dr. Nelles Silverthorne and Dr. Patricia Armstrong led research) in Dufferin County and at Orangeville, and a team of technicians, headed by Dr. Rhodes, isolated the Coxsackie virus in the Connaught Laboratories from samples obtained in Dufferin County. This was the first instance in which the Coxsackie virus was isolated in Canada. The field work in Dufferin County has been continued through the past three years, together with the attendant bacteriological research at the Connaught Laboratories. This program has the financial assist- ance of the Canadian Life Insurance Officers' Association.
Dr. Dalldorf has found that the Coxsackie virus appears to protect white mice from the virulent types of polio. Dr. Rhodes feels that the search for a protective vaccine should not proceed only along the line of using the Coxsackie virus.
Part of the Toronto research, then, has been directed, with considerable success, toward growing polio virus in tissue cultures. Not in the living flesh of animals, but in cells kept alive in flasks. Dr. John Enders of Harvard spoke in detail of similar experiments conducted in the United States when he addressed the Copenhagen conference.
Polio virus is subvisible - it can hardly be seen with the electron microscope, which gives magnification up to and beyond 100.000 diameters. In the Hospital for Sick Children and in the Connaught Laboratories, workers are protected by germicides, germicidal lights and working cabinets which reduce possibilities of infection to a minimum. With a source of active virus at hand, the possibilities before the 5 Toronto program are:
- Development of a protective vaccine from the destroyed product of the virus. That is, production of a vaccine in which all the germs of the virus have been killed, thus) making the product safe for use.
- Development of a protective culture from weakened strains of one or a mixture of the three strains of polio virus. The three, strains are distinguishable from other only by the fact that recovery of a laboratory animal from one strain will not afford that animal protection from dangerous doses of another strain. Production of a vaccine in this way would follow much the same process as that used in the production of smallpox vaccine.
- Development of a protective vac cine from the Coxsackie virus.
Now, it has been recognized that| the Coxsackle virus provides a measure of protection from polio for white mice. In any of the three possibilities the research workers would have to produce a protective d/culture, try it first on white mice, then on other animals, and repeat and check their experiments a thousand times over before they would be willing to suggest they had a vaccine which would give protection to humans.
There will be no lack of support for the program Dr. Rhodes has visualized. And, since, he is a graduate of Edinburgh University, and e a carefully trained scientist, Dr. Rhodes is not disposed to sacrifice certainty for speed.