Listeriosis is a foodborne bacterial infection caused by Listeria monocytogenes. It is one of the serious and severe foodborne diseases. It is a rare disease with an incidence of 0.1 to 10 cases per 1 million people per year in 2018 depending on the countries and regions of the world. Even though the number of cases is low the rate of death associated with listeria infection is high.
How Common is Listeria?
Here are some data from different countries about the incidence of Listeria monocytogenes in the recent past years.
How Common is Listeria in United States?
The estimated annual incidence of listeriosis is approximately 2 to 3 cases per million populations. In the United States, an estimated 1,600 people get listeriosis every year.
- Listeriosis related mortality rates decreased annually by 10.7% from 1990 through 1996, and by 4.3% from 1996 through 2005.
- In 2010 the incidence of listeriosis in Unites states was 0.27 per 100,000 people. Listeria infection occurs by consuming contaminated food. Listeria is one of the most virulent foodborne pathogens with up to 20% of infections resulting in death.
- In a study of reported listeria cases from 2009-2011, the CDC reported a case fatality rate of 21%. Almost all cases occurred in high-risk groups, including older adults, pregnant women, and people who were immunocompromised.
- However there have been several outbreaks reported in USA
- 2015 in 4 states – 10 cases were reported and 3 deaths.
- 2016 in Ohio – 19 cases were reported and 1 death.
- 2017 in New York – 8 cases were reported and 2 deaths.
- As you see the number of cases with listeriosis has gradually reduced and with that the number of deaths also has reduced. However even with the small number of infected people the death rate remains significantly high.
How Common is Listeria in European Countries?
- There were 32 cases identified between December 2015 and February 2018 in the above European countries. There were six deaths reported.
- There were few cases in Denmark, Portugal reported from 2010 -2014. There were 71 cases and 28 deaths among those cases.
South Africa
There was recent outbreak in South Africa. There were 999 cases of Listeria and 191 deaths. This was the largest Listeria outbreak in the world.
Incidence of Listeriosis in Pregnant Women and Newborns
- The incidence of listeriosis in pregnancy is 12 per 100k, compared with a rate of 0.1 to 10 per 100k in the general population.
- It is 20 times more common in pregnant women than in the general population.
- The CDC monitors cases of listeria infection, and estimates that there were about 800 cases in 2007. Cases were spread evenly throughout the United States.
- Based on known incidences, approximately 200 of those likely occurred during pregnancy.
- The incidence of listeriosis in the newborn is estimated at a rate of 8.6 per 100k live births. Neonatal listeriosis is often severe, with a mortality rate of 25-50%.
- Nearly all pregnancy cases of listeriosis occur in healthy women with no additional precipitating risk factors.
- Listeriosis mainly diagnosed in the third trimester. But infection that occurred during the first trimester may be unreported because most of those pregnancies end up in a miscarriage.
Conclusion
Listeria infection is a public concern in many parts of the world. Incidence of 0.1 to 10 cases per 1 million people per year in 2018 depending on the countries & areas of the world. The incidence of listeriosis in pregnancy is 12 per 100K, compared with a rate of 0.1 to 10 per 100K in the general population. It is 20 times more common in pregnant women than in the normal population. The incidence of listeriosis in the newborn is estimated at a rate of 8.6 per 100K live births. Even though the reported cases are low, the confirmed cases represent just the tip of the iceberg; there may be more unreported cases or self-limiting cases. The number of death among reported cases are high. Most of these deaths occur in neonates, elderly people & in immunocompromised persons.
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