Source of world’s biggest listeria outbreak still unknown

THERE have been 748 confirmed cases of listeriosis in South Africa in the past year, making it the largest ever outbreak. So far, 67 people have died.

Listeriosis infections are caused by Listeria monocytogenes bacteria, usually in contaminated food such as raw meat and poultry, unwashed vegetables, and dairy products. It can lead to meningitis or blood poisoning in newborn infants, older people, and people with compromised immune systems. Infection during pregnancy can cause miscarriage.

Because symptoms can take between 6 hours and 10 weeks to appear, it can be difficult to identify the contaminated food responsible. “You wouldn’t know what you ate three weeks ago. This is the big challenge we face in this situation,” said Christian Lindmeier of the World Health Organization on 12 January.