Haemophilus influenzae (Pfeiffer influenza bacterium; ICD-10-GM A41.3: Sepsis due to Haemophilus influenzae; ICD-10-GM A49.2: Infection due to Haemophilus influenzae of unspecified location; ICD-10-GM G00.0: Meningitis due to Haemophilus influenzae; ICD-10-GM J14: Pneumonia due to Haemophilus influenzae; ICD-10-GM P23. 6: Congenital pneumonia caused by other bacteria) is a bacterium (gram-negative rod) that can cause upper respiratory tract disease by colonizing the mucous membranes of humans.
Haemophilus influenzae infection is classified according to ICD-10-GM as follows:
- ICD-10-GM J14: Pneumonia caused by Haemophilus influenzae.
- ICD-10-GM P23.6: Congenital pneumonia due to other bacteria – Haemophilus influenzae.
- ICD-10-GM G00.0: Meningitis due to Haemophilus influenzae.
- ICD-10-GM A41.3: Sepsis caused by Haemophilus influenzae
- ICD-10-GM A49.2: Infection caused by Haemophilus influenzae, unspecified location.
Serotypes a to f can be distinguished, with Haemophilus influenzae type b (Hib) being the most important. Furthermore, there is a distinction of unencapsulated (low virulence) and encapsulated strains. Haemophilus influenzae belongs to the hemophilic bacteria, which means that they require blood in order to multiply.
Haemophilus influenzae is found exclusively in humans.
Transmission of the pathogen (infection route) occurs either via droplets that are produced when coughing and sneezing and are absorbed by the other person via the mucous membranes of the nose, mouth and possibly the eye (droplet infection) or aerogenically (through droplet nuclei (aerosols) containing the pathogen in the exhaled air) or via contact infection (direct contact with secretions or contaminated objects).
The incubation period (time from infection to onset of disease) is usually a few days.
Sex ratio: Men are more frequently affected than women.
Peak incidence: Infections occur primarily in childhood and in immunocompromised adults.
The incidence (frequency of new cases) is approximately 0.3 cases per 100,000 population per year. In children under one year of age, the incidence is 1.6 cases per 100,000 inhabitants per year.
Course and prognosis: Haemophilus influenzae can cause a variety of different diseases. If Haemophilus influenzae B infection is diagnosed and treated in a timely manner, the prognosis is good.
The lethality (mortality related to the total number of people suffering from the disease) in untreated complicated infection, i.e. when meningitis (meningitis) develops, is 60-90%. Even with timely antibiotic treatment, the mortality rate is still more than 5%.
Vaccination: Vaccination against Haemophilus influenzae type b (Hib vaccination) is available and recommended by the STIKO for infants (from 2 months of age) and young children.
In Germany, the disease is notifiable according to the Infection Protection Act (IfSG) if Haemophilus influenzae is directly detected from cerebrospinal fluid/blood. The notification must be made by name.
