6–8 Although rare overall, PI3K inhibitor the frequency with which disease results following acquisition is influenced by host, environmental, and pathogen factors. Factors that increase the susceptibility to disease include asplenia, complement deficiency, and certain immunocompromising

conditions and genetic polymorphisms.3,9 Damage to the respiratory mucosa resulting from smoking, viral or bacterial co-infection, and environmental conditions may facilitate meningococcal invasion and development of disease. Most cases of meningococcal disease in industrialized countries are sporadic, occurring without secondary transmission, but persons who are at close contact with those with disease are at up to 800-fold higher risk for developing disease than those without such

exposure.10 Certain bacterial lineages have increased propensity to cause disease.11 Disease usually develops within 1 to 14 days following acquisition.3 Initial symptoms may be nonspecific or resemble viral upper respiratory tract infections. Later symptoms reflect localization, this website and include intense headache, nausea, vomiting, stiff neck, and photophobia in the case of meningitis, and maculopapular, purpuric, or petecheal rash in the case of bloodstream infection. Delirium and coma often appear.10 Meningococcal meningitis is the most commonly recognized presentation globally, accounting for 80% to 85% of all reported cases of meningococcal disease, although bloodstream infection may be under-recognized. The remaining 15% to 20% of cases are most commonly bloodstream infection or pneumonia, but pericarditis, conjunctivitis, urethritis, and arthritis can also occur.12 Meningitis can occur with or without septicemia. Meningococcal meningitis

has a case-fatality rate of 5% to 10% even with timely antibiotic therapy.13 In addition, 12% to 19% of survivors develop long-term neurologic sequelae.10,14 Severe bloodstream infection, or meningococcemia, may present as purpura fulminans and is associated with an increased OSBPL9 case-fatality rate. Meningococcal disease incidence is strongly influenced by age group, socioeconomic conditions, serogroup, and bacterial strain as determined by multilocus sequence type. Tremendous variability is observed in meningococcal disease incidence by country and region (Figure 1), and in recent years the implementation of vaccination programs in many countries has begun to reduce the incidence of meningococcal disease. Serogroups A, B, and C account for up to 90% of the disease globally, but with much global variation observed in the relative contribution of each.15 In industrialized countries, implementation of chemoprophylaxis recommendations for persons in close contact with meningococcal disease case-patients has effectively reduced the occurrence of secondary cases.16 However, N meningitidis also causes epidemic meningitis.