Symptoms | Listeria | CDC
www.cdc.gov › listeria › symptomsMay 03, 2022 · The bacteria are most likely to sicken people who are pregnant and their newborns, adults aged 65 or older, and people with weakened immune systems. Other people can be infected with Listeria, but they rarely become seriously ill. Invasive illness Invasive means bacteria have spread beyond the intestines (gut).