Haemophilus influenzae type b (Hib) causes pneumonia, occult febrile bacteremia, meningitis, epiglottitis, septic arthritis, cellulitis, otitis media, purulent pericarditis, and other less common infections, such as endocarditis, endophthalmitis, osteomyelitis, and peritonitis. Nontype b encapsulated strains occasionally cause invasive disease similar to type b infections. Nontypable strains more commonly cause infections of the respiratory tract (eg, conjunctivitis, otitis media, sinusitis, pneumonia) and, less often, bacteremia, meningitis, chorioamnionitis, and neonatal septicemia.