International travel and health



The bacterium Listeria monocytogenes.


Listeriosis affects a variety of animals. Foodborne infection in humans occurs through the consumption of contaminated foods, particularly unpasteurized milk, soft cheeses, vegetables and prepared meat products such as pâté. Unlike most foodborne pathogens, Listeria multiplies readily in refrigerated foods that have been contaminated. Transmission is also possible from mother to fetus or from mother to child during birth.

Nature of the disease

Listeriosis causes meningoencephalitis and/or septicaemia in adults and newborn infants. In pregnant women, it causes fever and abortion. Newborn infants, pregnant women, the elderly and immunocompromised individuals are particularly susceptible to listeriosis. In others, the disease may be limited to a mild acute febrile episode. In pregnant women, transmission of infection to the fetus may lead to stillbirth, septicaemia at birth or neonatal meningitis.

Geographical distribution

Worldwide, with sporadic incidence.

Risk for travellers

Generally low. Risk is increased by consumption of unpasteurized milk and milk products and prepared meat products.




Avoid consumption of unpasteurized milk and milk products. Pregnant women and immunocompromised individuals should take stringent precautions to avoid infection by listeriosis and other foodborne pathogens (Chapter 3).