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LISTERIOSIS

What is Listeriosis ?

Listeriosis is caused by a bacterium called Listeria which was first described over 60 years ago. This organism is widespread in animals and nature. It has been found in dust, mud, sewage and animal stools. Listeria does not often cause human infection, but there has been an increase in the number of cases during the last few years. The disease mainly affects pregnant women and people with poor defence to infection, for example the elderly. Listeriosis can be mild or severe. It can cause a fever, chills, fatigue and muscle pain. In pregnant women it may lead to miscarriage or stillbirth. Listeriosis in the newborn baby may lead to difficulty in breathing, chest infection, and inflammation of the coverings of the brain (meningitis). In the adult patient listeria may rarely cause meningitis and serious bloodstream infection. Most infections occur in patients in whom another disorder results in a poor body defence against infection. It can rarely affect healthy adults through eating food contaminated with the organism. There has been a great deal of interest recently concerning listeria in food products. The organism has been isolated from poultry (both fresh and frozen), eggs, cow's milk, cook-chill food, soft cheese, etc. Considering that the organism is so widely distributed in the environment, it is hardly surprising that it finds its way into food products. Also the unusual fact that listeria can multiply at 4 to 6 C (refrigerator temperature) adds to the problem of ready prepared food . Despite this, listeria infection has rarely been connected with food consumption in the UK.

How does Listeriosis occur ?

In most human infections, it is not clear how the germ gets into the body. It has been suggested that the bacteria may spread from the gut to various parts of the body, probably through the bloodstream. In pregnant women the organisms pass from the infected mother to the foetus or newborn.

Why does Listeriosis occur ?

Most people who are exposed to listeria do not suffer any ill-effect. The factors which predispose to listeriosis include pregnancy, cancer, anti-cancer drugs, kidney transplant, diabetes and advanced age.

Treatment Involved for Listeriosis

Listeriosis diagnosed during pregnancy or in the newborn usually requires admission to hospital. So do severe forms of the disease, such as meningitis in adults. These infections are treated with antibiotics (penicillin or erythromycin).

During Treatment for Listeriosis

This depends on the type of listeria infection. Symptoms in pregnant women usually get better within a few days. The newborn may be severely affected: the disease may even prove fatal. Meningitis may get better, but many patients already have other severe underlying diseases as well, which can affect the outcome.

After Treatment for Listeriosis

Once treated, recurrence of the infection is very rare indeed.

If Listeriosis is Left Untreated

Listeria infection in pregnancy may subside on its own. Rarely, the infection may cause labour to start. If not treated vigorously, the rare listeria meningitis may be fatal.

Effects on Family of Listeriosis

Those involved in food shopping and preparation should take particular care. Pregnant women, and people known to have disorders which produce decreased resistance to infection, must avoid eating soft cheeses (like Brie, Camembert or blue cheeses) and meat based pate. They should heat properly all cook chill foods and ready prepared poultry. Storage instructions, sell-by dates and eat-by dates of food products should be strictly observed.