Listeria infection may lead to complications like blood infection, meningitis, or encephalitis. Death is the most severe consequence of listeriosis.
For those persons who suffer a Listeria infection that does not resolve on its own, the complications can be numerous and possibly severe. The most common complication is septicemia (bacterial infection in the blood), with meningitis being the second most common. Other complications can include inflammation of the brain or brain stem (encephalitis), brain abscess, inflammation of the heart-membrane (endocarditis), septic arthritis, osteomyelitis (infection in the bone), and localized infection, either internally or of the skin.
Death is the most severe consequence of listeriosis, and it is tragically common. The CDC has estimated that Listeria monocytogenes is the third leading cause of death from foodborne illness, with approximately 260 of 1,600 people dying from their infections. For example, based on 2018 FoodNet surveillance data, 96% of 126 Listeria cases ended up in the hospital, the highest hospitalization rate for pathogenic bacterial infection. This data showed a fatality rate of 21%. According to the FDA, case-fatality rate increases substantially based on complications, possibly reaching rates of 70% in cases with listerial meningitis, 50% in septicemia cases, and over 80% for perinatal/neonatal infections. In one U.S. study, L. monocytogenes was reportedly the cause of nearly 4% of all cases of bacterial meningitis.