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    Infectious Disease Control Unit
    Mail Code: 1960
    PO BOX 149347 - Austin, TX 78714-9347
    1100 West 49th Street, Suite T801
    Austin, TX 78714

    Phone: (512) 776-7676
    Fax: (512) 776-7616


Haemophilus influenzae

h influenzae

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Organism, Causative Agent, or Etiologic Agent

Invasive Haemophilus 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. 


Direct contact with respiratory droplets from a carrier or case patient.


Although 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.

School Exclusion Policy

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 childcare.

texas trendsRecent Texas Trends

Prior to 2016, only invasive disease caused by H. influenzae type b (Hib) was reportable. Hib disease is rare in Texas. Since 2000, there have been 2-15 cases reported each year in Texas with 15 reported in 2016. Most cases of H. influenzae occur in older adults with other underlying conditions that make them susceptible to H. influenzae.


Last updated June 27, 2018