Toxoplasma

Toxoplasma is the parasite responsible for causing ‘toxoplasmosis’–a type of food poisoning which is rare but nevertheless, can cause an unpleasant illness.

Toxoplasmosis causes mild symptoms which soon resolve themselves and without any long term effects. But this illness is serious in people with a compromised immune system or pregnant women.

The risks for pregnant women include damage to the unborn baby or even miscarriage.

This is covered in more detail in our pregnancy and food poisoning section.

The toxoplasma parasite

The ‘toxoplasma gondii parasite is found within the digestive systems of several animals and birds but is more commonly associated with cats.

Causes of toxoplasmosis food poisoning

Transmission of this parasite from animal to human occurs via the consumption of infected meat, e.g. pork or from contact with infected cat faeces or soil.

One example of this transmission is touching a cat’s litter tray.

Other causes include eating undercooked meat or handling chopping boards, utensils etc which have been in contact with infected food.

Sliced cooked meats such as ham or salami are another risk as is unpasteurised goat’s milk.

Symptoms of toxoplasmosis food poisoning

The parasite enters the human body during consumption where it invades cells within the lining of the intestine before spreading into the bloodstream.

Once in the bloodstream it travels around the body causing a wide range of symptoms which are very similar to ‘the flu’.

The period of time between exposure to the parasite and the appearance of the symptoms –the ‘incubation period’–is from a few days through to a month.

Most people do not realise that they have been infected with this illness as it doesn’t cause any symptoms. Their immune systems are able to fight off this illness and they retain this immunity for the rest of their lives.

But some people do develop this infection although this is usually a mild version.

This illness develops in two stages – ‘acute toxoplasmosis’ (first stage) and ‘latent toxoplasmosis’ (second stage).

Acute toxoplasmosis

This first stage includes the following symptoms:

• Swollen glands
• Aches and pains
• Fever
• Skin rash (occasional)
• Nausea

These can persist for a couple of months of even longer. This stage is often known as acute toxoplasmosis and can develop into a severe form in people who have weakened immune systems, pregnant women or young children.

This severe form often leads to complications such as encephalitis (inflammation of the brain) or necrotising retinochoroiditis which occur in both adults and children. Newborn babies can also experience either of these or nasal deformities although this tends to be very rare.

Latent toxoplasmosis

The second stage is known as ‘latent toxoplasmosis’but those who develop this illness are unaware that they have been infected. They don’t usually show any symptoms or if they do, not until later on in life.

This applies to babies who contract this parasite whilst still in the mother’s womb but only develop these symptoms at a later stage in their lives.

One exception is people who have weakened immune systems who will go on to develop the latent form of this illness.

Diagnosing toxoplasmosis food poisoning

This involves a blood test. This test is carried out to see if your immune system has produced antibodies as a reaction to the toxoplasma parasite.

This blood sample is sent to a laboratory to confirm (or reject) this diagnosis.

Treatment for toxoplasmosis food poisoning

Most cases of toxoplasmosis resolve themselves without the need for treatment.

But acute forms of this illness will require medication such as pyrimethamine and sulfadiazine. Pyrimethamine is a medication used to treat malaria whereas sulfadiazine is an antibiotic which is prescribed in conjunction with pyrimethamine.

Pregnant women are often given spiramycin which is another type of antibiotic, commonly used to treat toxoplasmosis.

Latent toxoplasmosis is treated with either of these antibiotics – clindamycin or atovaquone.

Your treatment plan will be discussed between you and your GP. This will depend upon the severity of your illness as well as your overall health.

You may need to remain on medication for the rest of your life is you have an underlying condition, an autoimmune disease or a weakened immune system, e.g. HIV.

Toxoplasmosis food poisoning and pregnancy

There are particular risks for women who contract toxoplasmosis during their pregnancy. This infection passes from the mother to the baby via the placenta and is known as ‘congenital toxoplasmosis’.

The main risk is that this infection causes harm to your developing baby which may lead to a premature birth or even worse, a miscarriage.

The extent of the risk will depend upon the stage of the pregnancy at which the infection occurs. This manifests itself in the following two ways:

• Infection at an early stage of pregnancy will increase the risk of miscarriage (or stillbirth).
• Infection at a late stage of pregnancy will directly affect the baby and its development.

This infection can affect the baby at a very early stage of its development although this is very rare. But if it does happen it is likely to cause serious health problems. These health problems include seizures and eye complaints.

However, if this infection occurs later on in pregnancy it results in fewer health problems in the newborn baby.

This type of toxoplasmosis tends to occur following the consumption of infected meat rather than contact with infected cat faeces or soil.

But this does not completely rule out this risk.

So, it is a good idea to avoid changing a cat’s litter tray and to wash your hands after stroking a cat especially a sick cat.

Find out more about the risks of this and any other form of food poisoning in our pregnancy and food poisoning section.

Toxoplasmosis food poisoning and immune system disorders

We have already mentioned that people with a faulty or poorly functioning immune system are at greater risk of this infection. They are more likely to develop a severe form due to the fact that their immune systems are less effective at repelling this infection.

But there are also serious risks of complications which in some cases may be fatal. This is most likely to occur in people who are suffering from HIV/AIDS or are undergoing chemotherapy.

Two other risks which may result in permanent eyesight or brain damage include:

• Toxoplasmosis encephalitis
• Damage to the eyes (known as retinochoriditis)

Encephalitis is the medical name for a brain inflammation which includes symptoms such as headaches, seizures, lack of co-ordination and visual problems.

Retinochoriditis is a form of damage to the eyes in which lesions (wounds) develop on the retina or choroid (contains blood vessels). This can lead to cataracts or even a loss of eyesight in serious cases.

If you have a compromised immune system due to an autoimmune disease or cancer then it is as well to be aware of risk of contracting a severe form of this illness. Your GP or medical team responsible for your disease will be able to advise you further about this.

Preventing toxoplasmosis food poisoning

It is worthwhile adopting a few precautions to prevent toxoplasmosis especially if you have a weakened immune system or are pregnant.

These are the two highest risk groups for this infection so if you fall into either one of these then it is important to take extra care.

This includes:

• Avoid eating raw or undercooked food, for example lamb or pork.
• Wear gloves when gardening and avoid touching soil if possible. If you do then wash your hands thoroughly afterwards.
• Do not touch or stroke stray or feral cats
• Avoid drinking unpasteurised goat’s milk
• Wash chopping boards, kitchen utensils and surfaces after preparing food preparation. This is particularly important if you have handled raw meat or poultry.
• Wash any fruits and vegetables before consumption
• Avoid touching or coming into contact with cat faeces, for example emptying a litter tray. Ask someone to do this for you if possible.
• Reduce the risk of infection from cat faeces by giving your cat dried or tinned cat food rather than fresh meat.

Screening for toxoplasmosis is not normally undertaken in the UK so it is worthwhile following these precautions to reduce the risk.