THE EMERGENCE OF HAEMOPHILUS-INFLUENZAE TYPE-E AND TYPE-F AS SIGNIFICANT PATHOGENS

Non-type b encapsulated Haemophilus influenzae meningitis (two cases d ue to H. influenzae type e, two due to H. influenzae type f) was diagn osed in four children in a 6-month period at the University of Virgini a. H. influenzae type b was the most common cause of bacterial meningi tis in the United States before the introduction of an effective vacci ne, whereas the other five encapsulated serotypes of H, influenzae rar ely caused invasive disease, The clinical features of non-type b H. in fluenzae meningitis and the therapy for this infection are the same as those for type b H. influenzae disease. We report these four cases to document an increase in infection due to non-type b serotypes of H, i nfluenzae, and we postulate that this change may result from the well- documented decrease in H. influenzae type b oropharyngeal carriage and disease that has occurred because of universal vaccination for H. inf luenzae type b.