ACUTE POLIOMYELITIS IN INFANTS UNDER ONE YEAR OF AGE: EPIDEMIOLOGICAL AND CLINICAL FEATURES

Abstract

In order to compare the epidemiological and clinical features of poliomyelitis in infants under 1 year with those in children and adults, a study was made of all cases of poliomyelitis that occurred in New York City in 1949 and 1950. This revealed the following characteristics of the disease among infants in the first year of life: Clinically recognizable poliomyelitis was of infrequent occurrence among infants under 1 year of age. It was even more infrequent among infants in the first 6 months of life. This is in marked contrast to the findings in the 1950 epidemic in Israel, where one-third of all cases occurred in the first year of life, and one-tenth in infants in the first half year of life. Male infants exhibited a greater susceptibility to the disease than females. Fatalities in this age group were high, particularly among infants under 3 months, with some predominance of deaths in males. Under 1 year of age, non-paralytic poliomyelitis was unusual, especially in the first 6 months of life. Paralytic forms of the disorder were dominant, spinal involvement being more common than bulbar. Case fatality occurred chiefly in bulbar forms of the disease, as in older children and adults. The fatality rate was higher than in older children and higher than in all ages combined. The onset of poliomyelitis among infants under 1 year of age was variable. It was acute, with fever, or fever with nuchal spasm, or the triad of fever, nuchal spasm and spasm of back muscles. Temperature at onset of illness averaged 98.3°F.(36.8°C.), with a low of 97.6°F.(36.3°C.), and a high of 102°F.(38.8°C.). Temperatures recorded subsequently during the day of onset of illness were from 99.9°F. (37.7°C.) to 105°F.(40.5°C.), the mean being 102.8°F. (39.3°C.). The interval between onset of illness and first detection of paralysis averaged 5.5 days, with a spread from the day of onset to 25 days later. Paralysis of a single limb occurred more frequently than of 2 or more limbs, and the ratio of arm to leg paralysis was about 1 to 3. Initial spinal punctures in infants under 1 year were made on an average of 3.4 days after onset of illness in non-paralytic cases, and 5.7 days in paralytic cases. The spinal fluid was usually clear, with a mean count of 91 lymphocytes/mm. . The average sugar content was 55 mg./and protein 72 mg./100 ml. of fluid.