Neurologic Infections in Travelers

Malveeka Sharma, MD, MPH; Joseph R. Zunt, MD, MPH

Disclosures

Semin Neurol. 2019;39(3):399-414. 

In This Article

Meningococcal Meningitis

Epidemiology

Meningococcal meningitis has been associated with six of the 12 serogroups of Neisseria meningitidis (A, B, C, W, X, and Y). The highest burden of meningitis occurs in babies, preschool children, and young adults. Due to a lack of adequate surveillance programs around the world, estimates of the global burden have been limited.[19] The greatest burden of meningitis is in sub-Saharan Africa, with estimates of 1,000 per 100,000 cases during the dry season (December–June).[20] The highest rates of transmission occur in Ethiopia, Nigeria, and Burkina Faso, with the meningitis belt that stretches across sub-Saharan Africa from Senegal to Eritrea.[2] The largest travel-related outbreaks of meningococcal meningitis have occurred during the annual Hajj pilgrimage in Saudi Arabia, with an incidence of 640 per 100,000 pilgrims during the 2,000 pilgrimage.[20] Even with adequate medical care, case-fatality rates can reach 22%, and more than 10% of survivors develop neurological sequelae. Therefore, prevention through vaccination has been the primary target for decreasing meningococcal meningitis.

Life Cycle, Ecology, and Species

Neisseria meningitidis is a gram-negative diplococcus that only infects humans. Transmission is via respiratory or salivary secretions, and 1 to 10% of the populations have nasopharyngeal colonization. The bacterium rapidly multiples in the bloodstream, allowing efficient identification.[21] Virulence is variable and related to the presence of viral genetic material expressed by the bacterium.[21]

Clinical Manifestations

Meningococcal meningitis produces typical meningitis symptoms of stiff neck, headache, fever, and occasional light sensitivity. Infants may have a bulging anterior fontanelle. Case fatality is highest within the first 24 to 48 hours. When untreated, fatality is upwards of 50%. Long-term sequelae include learning disabilities, hearing impairment, behavioral issues, and chronic headaches—all of which are most commonly reported in young survivors.[22]

Diagnosis

Meningococcal meningitis is confirmed by the detection of N. meningitidis in CSF; if CSF samples are obtained after initiation of antibiotics, the detection rate drops precipitously.[23] PCR and latex agglutination assays offer an alternative means of diagnosis.[24]

Treatment

When meningococcal meningitis is suspected, parenteral antibiotics are typically started even before definitive diagnosis is made. Supportive treatment of shock and raised intracranial pressure, with aggressive fluid resuscitation and osmotherapy, respectively, are crucial. Cephalosporins and penicillin are the antibiotics of choice. For patients with penicillin allergy, chloramphenicol or meropenem can be used. Antibiotics are continued for a 5- to 7-day course.[24] Close contacts should also receive chemoprophylaxis with either rifampin or ceftriaxone.[24] There are multiple available vaccinations available that contain a variable number of serogroups. Currently, there are three quadrivalent polysaccharide conjugate vaccines available that target serogroups A, C, W, and Y. Vaccination is required prior to making the Hajj pilgrimage. Unfortunately, current vaccines confer at most 3 to 5 years of protection and produce varying degrees of herd immunity.[19]

Comments

3090D553-9492-4563-8681-AD288FA52ACE

processing....