Attempts to Produce Poliomyelitis in Refractory Laboratory Animals. ∗

Abstract

Since the successful transmission to monkeys of the virus of poliomyelitis by Landsteiner and Popper, 1 many attempts have been made to produce the disease in the other laboratory animals. This work has been adequately reviewed by Shaughnessy et al. 2 and Harrington. 3 Experiments concerned with transmission of the virus to any animal other than the monkey have given only negative results. In this work, the passage and multiplication of the virus of poliomyelitis was attempted in mice, rats, guinea pigs and rabbits. It was thought possible to overcome the factors which make these animals naturally resistant to the virus, by using very young animals, by lowering their resistance and by passing the virus serially in the hope of adapting it to the new host.

First, to determine the time of survival of the virus in the brains of these animals, they were injected intracerebrally and after various intervals of time, the site of inoculation was removed, emulsified and injected into monkeys to determine the presence of virus. Rabbits received 0.3 cc., guinea pigs 0.2 cc., rats 0.1 cc., and mice 0.03 cc. of virus suspension. Table I indicates the time of removal of brain tissue and the subsequent reaction in monkeys inoculated with this tissue. The results are summarized in Table I.

It appears that the mouse is the best of the refractory animals for use in this work, since the virus survived in its brain for from 3 to 5 days. In the rabbit brain the virus is demonstrable 2 to 3 days after injection.

Attempts to Adapt the Virus to Mice and Rats by Serial Passage. White, male rats, six weeks old, received combined intracerebral, intraperitoneal and subcutaneous injections of 0.15 cc., 0.5 cc., and 0.3 cc., respectively, given 2 to 3 times during 24 hours.