Epidemic of meningitis and febrile illness in neonates caused by ECHO type 11 virus in Philadelphia.

Between April and November, 1980, an outbreak of meningitis and of febrile illness of neonates caused by ECHO 11 virus occurred in Philadelphia and surrounding communities. Thirty-eight virologically confirmed and ten virologically presumptive cases of meningitis were hospitalized in two Philadelphia hospitals for children. Most patients had fever and irritability. Vomiting, upper respiratory symptoms and poor feeding were present in one-third to one-half of the cases. Seventy-five percent of cases occurred between June 10 and August 18. The number of males and females was similar; 71% of children were 4 months of age or younger. This out break differed from those previously reported on enteroviruses in general, and on ECHO 11 virus in particular, in that no strong male predominance occurred and the patients were younger. A minimum attack rate of 4.1 per 1000 Philadelphia resident children ages 1 day to 4 months was estimated.