Haemophilus influenzae are virulent bacteria that are not responsible for the flu, but rather were the culprits in large outbreaks of meningitis affecting children younger than 5. According to the Center for Disease Control, before the Hib vaccine was released in the late 1990s, there were approximately 20,000 cases of invasive Haemophilus influenzae disease each year that resulted in hospitalization, severe disease or death. Approximately 12,000 cases of Hib-related meningitis were also reported in children younger than 5. The bacteria spreads through droplet transmission, and lives in nasal secretions and saliva.
Six Serological Types
There are six virulent forms of the bacteria that have been identified, according to the Louisiana Department of Health and Hospitals. Other, less dangerous, forms of the bacteria are not as virulent and do not often cause disease in adults or children. Asymptomatic colonization of the less virulent forms have been found in 60 to 90 percent of the throats of young children.
Pathogenicity
According to Pennsylvania State University, the bacteria can be a secondary invader when the flu virus is present, increasing the severity of disease. It is highly contagious, taking approximately three days to incubate in the body before symptoms appear. The duration of most illnesses is between 10 and 14 days.
The peak time of infectiousness, when the bacteria can be easily spread, is between days three and four after an individual has been infected. Although the bacteria spreads through droplet method and lives in highly humid environments, it is able to survive for up to 48 hours in a dry environment, according to Pennsylvania State University.
Vaccines
A vaccine for the b-type of Haemophilus influenzae significantly reduced the number of invasive diseases experienced by children. The Center for Disease Control and Prevention recommends that all children under the age of five are vaccinated for Hib diseases caused by Haemophilus influenzae bacteria. The vaccinations can sometimes be given in combination with other vaccines to reduce the number of shots a baby needs to have. Vaccines should start at the age of two months.
Diseases
Haemophilus influenzae bacteria cause meningitis, epiglotitis, bacteremia, pneumonia, septic arthritis, osteomyelitis, pericarditis and cellulitis, according to the Center for Disease Control and Prevention. The variety of diseases and bodily organs affected reflect the virulence and invasiveness of the bacteria. Approximately two-thirds of the children affected by meningitis prior to the Hib vaccine suffered effects such as hearing impairment, mental retardation, seizures and paralysis.
Antibiotic Resistance
According to researchers at the Department of Microbiology at the Institute of Medical Sciences in India, the emergence of antibiotic-resistant Haemophilus influenzae bacteria presents a large health threat. In an article published in 2001 in the "Indian Journal of Chest Diseases and Allied Sciences," researchers found that the majority of antibiotic resistance was to amoxicillin and the sulfa drug cotrimoxazole.
References
- Center for Disease Control and Prevention: Is Your Child Protected Against Hib Disease?
- Louisiana Department of Health and Hospitals: Haemophilus Influenzae Invasive Disease
- Pennsylvania State University: Bacteria: Haemophilus Influenzae
- "Indian Journal of Chest Diseases and Allied Sciences"; Drug Resistant Haemophilus Influenzae from Respiratory Tract Infection in a Tertiary Care Hospital in North India; V.L. Nag; 2001
- VPD Surveillance Manual: Center for Disease Control and Prevention: Chapter 2: Haemophilus Influenzae Type b Invasive Disease
