Haemophilus influenzae infection

	Haemophilus influenzae infection Main page
Patient Information
Overview
Causes
Classification Pneumonia Bacteremia Meningitis Epiglottitis Cellulitis arthritis Otitis media Conjunctivitis
Pathophysiology

This page is about clinical aspects of the disease. For microbiologic aspects of the causative organism(s), see Haemophilus influenzae.

For patient information about Haemophilus influenzae infection, click here | Haemophilus influenzae type b (Hib) vaccine, click here.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: Hib disease

H influenza infection

Overview

H.influenzae is a type of bacteria that can cause infections in people of all ages ranging from mild, such as an ear infection, to severe, such as a bloodstream infection.

Causes

Haemophilus influenza disease is caused by the bacterium Haemophilus influenza.
There are six identifiable types of H.influenza (a through f) and other non-identifiable types (called nontypeable).
The most common type of H.influeza that is most familiar is H. influenza type b, or Hib.
These bacteria are a normal commensal of throat and nose. However, the bacteria can sometimes move to other parts of the body and cause infection.
Some of these infections are considered “invasive” and can be very serious.

Classification

H. influenzae, including Hib, can cause many different kinds of infections. These infections can range from mild ear infections to severe diseases, like bloodstream infections. When the bacteria invade parts of the body that are normally free from germs, like spinal fluid or blood, this is known as "invasive disease." Invasive disease is usually severe and can sometimes result in death.
The most common types of invasive disease caused by H.influenza are: