Causative Agent, or Etiologic Agent
influenzae disease can be caused by six identifiable types of H. influenzae bacteria (types a through
f) or non-typeable H. influenzae
bacteria. Haemophilus influenzae,
type b (Hib) usually causes the most severe disease and is the only type that
is vaccine preventable. However, all cases of invasive Haemophilus influenzae disease are reportable in Texas.
contact with respiratory droplets from a carrier or case patient.
all types of Haemophilus influenzae can
cause illness, Hib is most often the cause of severe disease. The most common
and severe manifestation of invasive Haemophilus
influenzae disease is meningitis (inflammation and swelling in the
coverings of the brain and spinal cord). Symptoms of meningitis include fever,
weakness, vomiting, and a stiff neck. Hib and other types of H. influenzae can also cause infection
of the lungs, blood, joints, bones, throat, and covering of the heart. Symptoms
depend on the part of the body affected.
Invasive Hib disease can be prevented by
giving the Hib vaccine to kids 2-18 months of
age. Also, Hib and other types of H.
influenzae can be prevented by maintaining respiratory isolation for
patients and applying good hand-washing technique.
Children with bacterial meningitis, like that caused by Haemophilus
influenzae, should be kept out of school or childcare until they
have written permission from a healthcare provider and until they are fever
free for 24 hours without the use of fever suppressing medications.
Rules for exclusion of sick children from school and childcare are outlined in
the Texas Administrative Code, specifically Rule 97.7 for
schools and Rule 746.3603 for
Recent Texas Trends
Prior to 2016, only invasive disease caused by H. influenzae type b was reportable. Hib disease is rare in Texas. Since 2000, there have been 2-12 cases reported each year in Texas with 11 reported in 2015. Most cases occur in older adults with other underlying conditions that make them susceptible to H. influenzae.