PROSPECTIVE STUDY OF A MIXED COXSACKIE VIRUS B3 AND B4 OUTBREAK OF UPPER RESPIRATORY ILLNESS IN A CHILDREN'S HOME

In the late summer of 1968 an outbreak of moderately severe upper respiratory illness occurred among the 120 children living in a children's home. Coxsackie viruses B3 and B4 were isolated from throat swabs and eye swabs of 21 children who were clinically ill. Neutralization tests were performed on serum specimens collected from each child before, during, and after the outbreak. Fifty-two percent of the children in the home experienced an infection with B3 or B4, 10% were sequentially infected with both types, and 38% remained uninfected. Coxsackie B3 accounted for 57% of all infections, and B4, for 43%. Infection was clearly related to age, and to preexisting antibody. Preexisting B3 and B4 serum neutralizing antibody levels of 1:20 and greater were fully protective against reinfection by the respective virus type. These viruses caused a wide spectrum of symptoms and physical findings which ranged from inapparent infections to aseptic meningitis. Conjunctivitis, exudative tonsillopharyngitis, otitis, and enanthem, were more frequently associated with B3 than B4, and aseptic meningitis was more frequently associated with B4 than B3. One child, experiencing a distinctly biphasic pattern of illness, exhibited a delayed antibody response concomitant with persistent virus shedding from the throat for a duration of 57 days. Using figures corrected for the effect of protective preexisting antibody, the reported illness rate for Coxsackie B3 in the total population was 24%, and the unreported illness rate was 21%; the ratio was 1:1. For type B4, the reported rate was 18% and the unreported rate 38%, for a 1:2 reported: unreported ratio.