A study of the global burden of listeriosis, the illness caused by Listeria monocytogenes bacteria, has been conducted by the World Health Organization (WHO) and published in the journal Lancet Infectious Diseases. The study’s authors reviewed 12,000 studies on Listeria infections published from January 1, 1990 to May 21, 2012. Listeria bacteria are difficult to control, partly because they can grow at refrigerator temperatures, in low-water foods, and aren’t easily destroyed with cleaning materials.
Listeria monocytogenes infected more than 23,000 people worldwide in 2010. Of those, 5,463 were killed. This is a far higher rate of death than those caused by Salmonella infections. This poses an urgent effort to discover more about the bacteria and its prevalence in developing countries. Countries that have almost half of the world’s population do not report Listeria illnesses.
The analysis estimates disability-adjusted life-years (DALYs), which is a way to measure the loss of one year of health. The study found that listeriosis causes 172,823 DALYs globally in 2010.
Listeria disproportionally affects pregnant women. The bacteria can cause only a mild illness, but listeriosis can cause stillbirth, miscarriage, infant death, and infection of the newborn. More than 20% of those who contracted Listeria in 2010 were pregnant women, and almost 15% of those infections killed a baby.
Most cases of listeriosis are reported in high-income countries. In the United States, listeriosis is the third most costly illness, behind botulism and Vibrio. But Listeria monocytogenes is the highest burden on quality of life in Latin American countries, as well as Africa, India, Polynesia, and Southeast Asia.
WHO is planning to quantify the global burden of listeriosis, so it can be included as a disease in their international prioritization exercises. This is the first attempt at quantifying the bacteria’s effect.