The Incubation Period in Human Poliomyelitis and Its Implications

The incubation period in human poliomyelitis is not subject to exact analysis because of gaps in present knowledge concerning the mode of spread of the disease. Thus it is unknown what constitutes adequate exposure to virus in order to produce human infection, as well as what form (or forms) exposure may take. Furthermore, not only is there difficulty in knowing at what point the incubation period begins but there is some confusion about measuring its termination, i, e., a lack of agreement as to which shall be regarded as the first day of the clinical disease. It will be our purpose in this paper to review some of the existing data concerned with the incubation period in human poliomyelitis and to consider also its significance in terms of the pathogenesis of the disease. The incubation period in poliomyelitis is generally given in textbooks as ranging from six to twelve days,