How Infantile Paralysis Infection Is Passed On
( Originally Published 1936 )
Faced as we are every summer by the possibility of infantile paralysis, a valuable book for the public has been published, "Infantile Paralysis," by Dr. George W. Draper.
The practical questions that people want answered about the subject are such as: "Are my children likely to get it?" "How do they catch it?" "What can be done to prevent it?" "Should they be taken away from school or camp or resort where there have been one or two cases?" "What is the outlook for treatment when a case does occur?"
The cause of infantile paralysis is a virus—one of those germs too tiny to be seen even by the most powerful microscope. But we know the disease is infectious, and that the virus is actually an entity. When a monkey who has been infected with the disease dies, its brain can be removed and ground into an emulsion and passed through a filter. This clear filtrate, injected into another monkey's brain, will reproduce the disease.
So the virus exists. It shows remarkable variations in virulence as it passes through different monkeys. This accounts for the variable severity of different epidemics.
VIRUS TENACIOUS OF LIFE
The virus of infantile paralysis is also very tenacious of life. It can be kept in glycerin in an ice box over a year without losing its activity. It resists freezing. Different chemicals affect it entirely differently—it is remarkably resistant to carbolic acid, while hydrogen peroxide, menthol and bichloride of mercury destroy it rapidly.
Reproducing conditions as they exist in nature, the infantile virus will survive indefinitely if surrounded by a moist, warm albuminous medium, such as the nasal secretions.
This is the mode of its spread. It is a carrier disease. Someone who has either had the disease or been in contact with one who had it, has the virus implanted in his nasal cavity and carries it about giving it to others.
People vary in susceptibility also, and whether you or your children catch it depends a great deal on this susceptibility in the presence of an epidemic.
The virus almost certainly enters the body by the nose, and from the nose it travels along the nerves of smell to the brain and central nervous system. It has an especial affinity for nerve tissue, and particularly the motor cells of the spinal cord.
Naturally, during an epidemic or the epidemic period, the avoidance of as many human contacts as possible is sensible. With the occurrence of one or two cases in an institution such as a school, it would seem the part of 'wisdom to close the school. If for no other reason, for psychological ones. The scholars who have been exposed but are still unaffected, often go into a kind of panic, and their return home is imperative on humanitarian grounds.