Toxoplasmosis

In about 80 per cent of cases, toxoplasmosis causes no symptoms and you are not even aware that you are infected. In healthy adults and children, the immune system is usually strong enough to prevent the T. gondii parasite (which causes toxoplasmosis) from causing any illness. You become immune to it and it will live harmlessly in your body for life.

However, in some cases, toxoplasmosis can cause the lymph nodes (glands that form part of your immune system) to swell, particularly in the throat or armpits. This can cause symptoms that are similar to the flu including:

• body, or muscle, aches,
• a high temperature (fever) of 38C (100.4F) or over,
• tiredness,
• feeling sick, and
• a sore throat.

It is very rare for otherwise healthy people to experience any serious symptoms of toxoplasmosis.

Pregnant women

If you become infected with toxoplasmosis, either while you are pregnant, or during the 2-3 months before you conceive, there is a chance that you could pass the infection onto your unborn baby (congenital toxoplasmosis).

While you will probably not experience any symptoms of the infection yourself, if this happens in the early stages of pregnancy, there is a risk of:

• miscarriage (the loss of a pregnancy during the first 23 weeks), or
• stillbirth (when the baby is born after 24 weeks of pregnancy without any signs of life).

One large study found that toxoplasmosis caused stillbirth in pregnant women in just less than one per cent of cases.

Around 30-40 per cent of pregnant women who become infected with toxoplasmosis will pass the infection onto their unborn baby, leading to congenital toxoplasmosis.

Symptoms of congenital toxoplasmosis

The symptoms of congenital toxoplasmosis vary depending on when the mother became infected. Symptoms are usually more severe if the mother was infected either just before becoming pregnant, or in the first and second trimesters (up to week 27 of the pregnancy).

Symptoms can include:

• hydrocephalus (water on the brain),
• brain damage,
• epilepsy (seizures),
• jaundice (yellowing of the skin and whites of the eyes),
• deafness,
• eye infections and blindness,
• an enlarged liver, or spleen (an organ that helps filter impurities from your blood),
• growth problems, or
• cerebral palsy (a condition of the brain and nervous system that affects a child’s movement and coordination).

If the mother becomes infected during the third trimester (from week 27 to the birth of the baby) there may not be any symptoms at birth. However, complications may develop later in life. For example, months, or even years, later a child born with congenital toxoplasmosis may develop:

• eye infections,
• hearing loss, or
• learning difficulties.

See the complications section for more information.

People with immune deficiencies

If you have a weakened immune system, toxoplasmosis can be fatal. This is because your body may not be able to fight off the infection. Your immune system may be weakened if:

• you have an illness that affects your immune system, such as HIV and AIDS, or cancer,
• you are having chemotherapy treatment, or
• you are taking immunosuppressant medication - for example, after having an organ transplant.

There is also a risk of developing permanent eye or brain damage. If toxoplasmosis begins to affect your brain, it can cause encephalitis (brain inflammation). This is sometimes called toxoplasmosis encephalitis (TE) and is one of the most frequent causes of death in people with HIV and AIDS.

Symptoms of TE include:

• headaches,
• confusion,
• poor coordination,
• seizures,
• chest pains,
• coughing up blood,
• difficulty breathing,
• a high temperature (fever) of 38C (100.4F) or over,
• problems with your vision, such as blurred vision and floaters (small pieces of debris that can cloud your vision),and
• multiple lesions (wounds) in the brain.