Listeria Food Poisoning Risky For Elderly And Pregnant Women

Seniors and pregnant women especially vulnerable to listeria infection

Adults over 65 years of age have a fourfold higher risk of listeria infection compared to the general population in the USA, while the risk for pregnant women is 10 times higher. Hispanic pregnant women are 24 times more likely to become infected and ill from listeria infection.

The report highlights the following groups at high risk of listeria infections – they represent over 90% of listeriosis diagnoses:

• Newborns
• Pregnant women – although not usually dangerous for the mother’s health, listeriosis can cause miscarriage, stillbirth, and premature birth. One sixth of all patients in America diagnosed with listeriosis are pregnant women.
• Seniors
• People with weakened immune systems, particularly cancer patients undergoing chemotherapy, as well as people with AIDS, diabetes, kidney disease, taking high-dose prednisone or certain rheumatoid arthritis drugs, and organ transplant recipients who are on immunosuppressant medications. According to the Health Protection Agency, UK, cancer patients have a 5-fold higher risk of developing listeriosis compared to others with an underlying disease

The authors of the Vital Signs report stressed that vulnerable people need to be aware of the dangers of listeriosis and how to reduce their risk of infection.

The CDC says that the new report provides a nationwide snapshot of 2009-2011 listeriosis incidence, plus which foods are linked to infection outbreaks.

Below are some highlighted data from the report:

• Over the three-year period, over 1,650 cases of listeriosis were reported to the CDC
• Approximately 1 in every 5 listeriosis cases resulted in the death of the patient
• Most deaths occurred among seniors, and as stillbirths and miscarriages
• Although pregnant mothers tend only to have mild symptoms, listeriosis significantly raises the risk of life-threatening infection in newborns
• Over the three-year period, there were twelve outbreaks in 28 states which made 224 people ill
• Of the 10 outbreaks where a food source was identified, six were caused by soft cheese (mainly Mexican-style cheeses), one by whole cantaloupe, and one by pre-cut celery

Tom Frieden, M.D., M.P.H., Director, CDC, said:

“Listeria strikes hard at pregnant women, the elderly, and people with weakened immune systems, sending many to the hospital and causing miscarriage or death in as many as one in five.

We need to develop new cutting edge molecular technologies to help us link illnesses and outbreaks to foods faster to prevent illness and death, which is why the President’s Budget proposes investing in new tools to advance this work.”

The CDC says that genetic fingerprinting of listeria through its PulseNet has helped identify several outbreaks of listeriosis, which led to some changes in food industry regulations.

By the early 2000s, listeriosis rates fell by approximately 25%. However, over the last few years incidence has leveled off. The CDC says that President Obama proposes an investment of $40 million for its Advanced Molecular Detection Initiative in the Fiscal Year 2014 budget. This investment would help improve the US public health system’s ability to protect Americans from disease and foodborne illness, the CDC wrote in a communiqué.

The CDC says it has plans to sequence the Listeria monocytogenes genome so that outbreaks can be detected and controlled more rapidly.

Certain strains of Listeria are adapted to infect heart tissue, raising the risk of serious heart disease. Dr. Laura Udakis, from the Society for General Microbiology reported in the Journal of Medical Microbiology (January 2011 issue) that developing new diagnostic tests to identify these fatal Listeria strains would protect vulnerable people.

Elisabeth Hagen, M.D., Undersecretary for Food Safety, U.S. Department of Agriculture, said:

“The lower rates of listeria infection attributed to meat and poultry over the past decade point to the success of prevention-based policies and industry best practices. However, important work remains if we hope to continue this momentum. Additional research and continual monitoring of evolving risks will allow us to develop policies that further reduce these illness rates.”

In a joint drive by the US Department of Agriculture (USDA) and the US Food and Drug Administration (FDA), nearly 27,000 ready-to-eat food samples from retailers were analyzed to determine their level (or not) of listeria. The two government departments plus the CDC say they will continue working with several states to identify which practices involved in the handling, storing and preparation of ready-to-eat foods might lead to cross-contamination.

Recent listeriosis outbreaks have been linked to foods that are not usually associated with listeria infection, highlighting the importance of new control measures to stop the bacterium from entering the food supply.

Michael R. Taylor, Deputy Commissioner for Foods and Veterinary Medicine, FDA, said “Through the 2011 Food Safety Modernization Act, FDA is developing rules aimed at preventing the introduction of Listeria and other dangerous bacteria into our food supply. We are also working with produce growers, food processors, and our state partners to further implement what we know works to minimize food safety risks.”

The CDC advises against the consumption of unpasteurized milk or soft cheese made from unpasteurized milk. People at high risk of listeriosis should make sure that hot dogs and deli meats are heated to 165° F (74° C) before consumption. Everyone should follow the practices of clean, separate, cook and chill.

Written by Christian Nordqvist