The Centers for Disease Control is investigating at least 100 reports of food poisoning, and 18 deaths, due to contaminated cantaloupes. DNA isolated from infected individuals has determined that Listeria is the responsible bacteria. Ninety-eight percent of 93 individuals contacted by monitoring agencies were hospitalized due to their infections. Because of lag times between consumption of these cantaloupes, illness, diagnosis, and laboratory confirmation, more cases are expected to occur.
Five percent of the human population has Listeria in its stool. It is also found in stools of non-human mammals, and birds. This may explain the fact that Listeria is found in water, soil, and animal feed.
Newborns, pregnant women, and individuals with immune disorders such as kidney disease, cancer, diabetes, and HIV/AIDS are at increased risk of becoming ill when infected with Listeria. In 89 % of cases, Listeria pass through the intestinal wall and enter the blood stream. From there, they are carried throughout the body and can end up in the brain, spinal cord, heart, eyes, liver, spleen, lungs, bones, and joints.
Instead of being attacked by immune cells, initially, Listeria hides in immune cells, multiplies, and infects other white blood cells. To stop the infection and return to immune balance, immune homeostasis, the body defends itself by releasing inflammatory and anti-inflammatory cytokines, cell messages, and antibodies, large proteins that mark the bacteria for destruction by inflammatory immune cells.
About half of adults with Listeria infection will be diagnosed with meningitis, an inflammatory condition of the brain and spinal cord. Endocarditis, inflammation of the inner lining of the heart, results in deaths of about 50% of patients.
So, ultimately, excessive inflammation kills infected individuals.