Listeriosis causes gastroenteritis; septicemia and meningitis. Almost all cases are transmitted by contaminated food. It is usually asymptomatic or a febrile gastroenteritis in healthy people. At increased risk are neonates, elderly, immunocompromised patients, and pregnant women.

8,700 (US); 23,150 (Global)
Listeria monocytogenes;
2-3 weeks; As long as 70 days has been reported; [CCDM] Often within 24 hours of ingestion of contaminated food; Invasive disease of pregnancy: 23 days (0-67 days); [PPID, p. 2545-6]
Gastroenteritis; septicemia and meningitis: Also endocarditis, granulomatous lesions in the liver, septic arthritis, osteomyelitis, cutaneous lesions, and stillbirth; [CCDM]
Almost all cases are transmitted by contaminated food. Enteric precautions are recommended. [CCDM, p. 355-7]
Usually asymptomatic or a febrile gastroenteritis in healthy people, but neonates, the elderly, immunocompromised patients, and pregnant women are at risk for severe manifestations of this infection: meningoencephalitis, septicemia, and septic abortion. Other rare forms of listeriosis include hepatic granulomas, skin infection (pustules and papules), and endocarditis. Other complications are coma (may appear early) and shock. [CCDM, p. 354-7] Meningitis diagnosis may be delayed because of subacute course and minimally abnormal CSF (WBC counts below 1000/uL in 75% of cases).

Infected pregnant women usually experience a flu-like syndrome. In newborns, the disease is often fatal. In addition to sepsis and meningitis, patients with non-perinatal listeriosis may present with brain abscesses, endocarditis, septic arthritis, osteomyelitis, and liver abscesses. [ID, p. 1633-7]

Gastroenteritis often precedes L. monocytogenes meningitis. Common symptoms are diarrhea, fever, headache, myalgia, and abdominal cramping. Rarely, skin infections with lymphadenitis have been reported. Complications of invasive disease are disseminated intravascular coagulation, ARDS, and rhabdomyolysis with acute renal failure. [PPID, 8th Ed, p. 2707-14] Conjunctival inoculation may seed oculoglandular listeriosis, septicemia, and meningitis. [Merck Manual, p. 1615]

The organism lives in soil, water, and silage. Domestic and wild mammals, fowl, and humans are reservoirs. Slaughterhouse workers and workers handling cultures in the lab have higher carrier rates. Outbreaks may be caused by contaminated food. The bacteria can grow in biofilms and at refrigerator temperatures. Most frequently contaminated foods are non-pasteurized milk or cheese, raw vegetables, cantaloupe, and ready-to-eat meats. The case-fatality rate for nonpregnant adults with invasive disease is 18%. "Veterinarians and farmers must take proper precautions in handling aborted fetuses and sick or dead animals, especially sheep that died of encephalitis." [CCDM] The organism does not grow in the standard media used for stool cultures. Occupational skin infections have been reported in veterinarians, ranchers, and poultry handlers. [ID, p. 1633-7] Most infections are foodborne. Outbreaks may be missed because normal hosts have mild illnesses and food supplies are increasingly centralized. About 5-10% of community-acquired meningitis in the US is caused by L. monocytogenes. [Harrison ID, p. 450] 20% of perinatal infections end in stillbirth or neonatal death. In the remaining infections, neonates are infected 68% of the time. [PPID, p. 2545-6] Infects more than 40 mammalian and avian species; [PPID, p. 2543]
Culture; Listeria may look like diphtheroids on Gram stain. Serology is unreliable. [CCDM] The selective media used for routine stool cultures will not isolate Listeria. [ID, p. 1636] MRI better than CT detecting rhomboencephalitis; [Cecil, p. 1885]
  • >arthralgia
  • >fever
  • >myalgia
  • G abdominal pain
  • G diarrhea
  • G nausea, vomiting
  • H lymphadenopathy
  • N confusion, delirium
  • N headache
  • N lethargy
  • N seizure
  • N stiff neck
  • O conjunctivitis, acute
  • O oculoglandular syndrome
  • S entry wound with lymph nodes
  • S lymphadenitis, acute
  • S papules or plaques
  • S pustule
  • *acute renal failure
  • *ARDS
  • *arthritis
  • *bleeding tendency
  • *brain abscess or lesion
  • *cranial neuropathy
  • *encephalitis
  • *endocarditis
  • *hepatitis
  • *meningitis
  • *myelitis
  • *myocarditis
  • *osteomyelitis
  • *paralysis
  • *pericarditis
  • *peripheral neuropathy
  • *pneumonia
  • *rhabdomyolysis
  • *sepsis
  • *shock
  • *stupor, coma




Ingestion, Skin or Mucous Membranes (Includes Conjunctiva)
Animal Tissue, Soil or Dust (Ingesting or Inhaling), Eating Contaminated Food, Eating Contaminated or Infected Meat, Eating Unpasteurized Milk or Cheese, Eating Contaminated Produce, Waterborne (Ingesting, Inhaling, or Swimming)
Birds and Poultry, Cattle, Goats and Sheep, Cats, Deer, Elk and Antelope, Dogs, Horses, Monkeys, Rabbits, Rodents, Swine, Human, Wild Animals
  • AIDS patients
  • Cancer patients
  • Consume unpasteurized milk/cheese
  • Handle animal carcasses or placentas
  • Ingest infectious agents in food/water
1. (US) Published in MMWR 2011: 870 cases; Use correction factor of 10 for reported diseases: 870 X 10 = 8700;
2. (Global) In 2010, listeriosis caused an estimated 23,150 illnesses and 54,463 deaths; [PPID, p. 2543]