Endemic and epidemic trends of poliomyelitis in Central and South America.

An inverse ratio between infant mortality rates and poliomyelitis case rates has been observed rather constantly in some parts of the world. The available data from Latin America have been examined in this connexion and, there also, the ratio seems to hold moderately well. A general supposition both for Latin America and elsewhere is that in countries where the infant mortality rate falls below 75 per 1000 live births, the poliomyelitis case rate will bear watching, since although the disease may not have been much of a problem in such countries in the past, experience has shown that it may suddenly or gradually become one.