Medicine: Virus for Polio

Scientists who have been experimenting with poliomyelitis (infantile paralysis) virus have been considerably hampered because the only animal they could infect was the expensive rhesus monkey. Last year Dr. Charles Armstrong of the U. S. Public Health Service finally succeeded in giving polio to ordinary cotton rats. That hurdle passed, he was able to pass the infection from cotton rats to mice.

Last fortnight, in the Rockefeller Journal of Experimental Medicine, Drs. Claus W. Jungeblut and Murray Sanders of Columbia University announced the next step: successful immunization of monkeys against polio. First they took a strain of live polio virus deadly to monkeys and injected it into a cotton rat. He frisked around apparently in perfect health. Then they passed a portion of his polio-saturated brain on to Rat No. II. He became mildly sick. A suspension of his brain, in turn, was given to Rat No. III. He became paralyzed, and his brain, when given to mice, killed them. But when the mouse brain, containing the powerful “murine” (mouse) virus, was given to a monkey, nothing happened. And when the monkey was given a stiff dose of the original deadly virus, shortly afterward, he developed a fever, but did not become paralyzed. Seven out of ten monkeys were thus immunized with murine virus.

Drs. Jungeblut and Sanders are still nowhere near ready to try murine virus on human beings. But they think they have discovered an entirely new approach to polio immunity—fighting one virus with another. It may be, they speculated, that murine virus, which is relatively harmless to monkeys, rapidly settles in their brain and spinal cord, “blockading” the deadly polio virus.