Toxoplasmosis
Toxoplasmosis is a very widespread infection: depending on the country, traces of a past encounter with this parasite are found in a third of adults, and in…
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Medicines commonly prescribed for Toxoplasmosis
For informational purposes only. Always consult a doctor before using any medicine.
Dosage form: TABLET, 160 mg trimethoprim; 800 mg sulfamethoxazoleActive substance: sulfamethoxazole and trimethoprimManufacturer: Teofarma S.R.L.Prescription requiredDosage form: ORAL SOLUTION/SUSPENSION, 200 mg sulfamethoxazole; 40 mg trimethoprimActive substance: sulfamethoxazole and trimethoprimManufacturer: Teofarma S.R.L.Prescription requiredDosage form: TABLET, 300 mg pyridoxine hydrochlorideActive substance: pyridoxine (vit B6)Manufacturer: Teofarma S.R.L.Prescription not required
Toxoplasmosis is a very widespread infection: depending on the country, traces of a past encounter with this parasite are found in a third of adults, and in some places in half. For almost everyone it passes unnoticed and needs no treatment at all. The subject becomes important in only two situations: in pregnancy, and in people whose immune defences are weakened. This page is written for them; everybody else needs only to know that there is nothing here to panic about.
How toxoplasma reaches people
The organism responsible is a single-celled parasite that multiplies in the intestines of cats and their relatives, but also lives in the tissues of many other animals, including the ones whose meat we eat. There are only a few routes into a human being, and all of them go through the mouth.
- Meat that has not been cooked through. Pork, lamb, game, mince still raw inside, a rare steak. Cured and cold-smoked products belong here too: salami, air-dried ham, home-made sausage.
- Soil. Gardening and working an allotment, unwashed vegetables, herbs and berries with earth still on them. This is a quiet and very common route that almost nobody thinks about.
- The cat's litter tray, but only one that has been left standing. There is a separate section on this below, because here the detail decides everything.
- Less often: unpasteurised goats' milk and products made from it, water of unknown origin, and the board and knife used for raw meat and then for salad.
Toxoplasmosis does not pass between people: not by kissing, not by coughing, not through shared cutlery. The one exception is passage from mother to baby during pregnancy, and that is what the rest of this page is about.
Why most people notice nothing
In someone with a healthy immune system the infection usually runs its course with no signs at all. Occasionally there is a spell of feeling unwell rather like a cold that drags on: a few days of a slight temperature, aching, tiredness and swollen glands, most often in the neck, which then stay up for weeks. It leaves nothing behind and needs no treatment.
After that the parasite settles into a dormant form and stays in the body for life, in muscle and nervous tissue, held in check by the immune system. There is one practical consequence: having had the infection protects against catching it again. A woman whose antibodies to toxoplasma appeared long before pregnancy can set the whole subject aside.
Rarely, even in entirely healthy people, the parasite causes inflammation inside the eye, in the retina. It shows itself as a blurred patch in the field of vision, floaters, or reduced sight in one eye, and it calls for an eye specialist rather than a wait-and-see approach.
A cat in the house: what not to be afraid of
The most persistent and least useful fear runs: "I am pregnant, I shall have to give the cat away." There is no need, and here is why.
A cat sheds the infectious form of the parasite only once in its life, over a few weeks after becoming infected itself, and it becomes infected by eating mice, birds or raw meat. A cat that lives in a flat, never goes out and eats prepared food is almost never the source of an infection.
The second thing that matters is time. What is shed is not infectious straight away: it has to ripen in the environment, and that takes anything from one to several days. From this comes a simple rule: a litter tray emptied every day is safe. What is dangerous is the forgotten tray, and old soil in a plant pot or a flowerbed.
And third: stroking the cat, sleeping beside it, picking it up, none of that passes anything on. The parasite lives neither in the fur nor in the saliva.
Pregnancy: where the real risk lies
The risk concerns only a recent infection, caught during pregnancy or shortly before it. An infection acquired months or years before conception is no threat to the baby.
A recent infection can pass to the foetus through the placenta. There is a pattern here worth knowing, because it explains how doctors act: the later in pregnancy, the more likely the parasite is to cross, but the milder the consequences usually are; the earlier in pregnancy, the less often it crosses, but the more severe it tends to be. Infection in the first weeks can end in miscarriage; later on it can damage the baby's eyes and brain.
Congenital toxoplasmosis is treacherous in another way too: at birth the baby often looks perfectly well, and the problem surfaces years later as failing sight. That is precisely why children in whom infection is confirmed are followed up and treated even when everything looks fine from the outside.
Keep a sense of proportion. The chance of catching it for the first time during those particular nine months is low, and the great majority of pregnancies have nothing to do with this subject at all. Prevention costs little and works well, which is why it is worth following, without anxiety, simply as a habit.
What lowers the risk during pregnancy
All of these measures apply equally to people with weakened immune defences.
- Do not eat raw or undercooked meat. Cook it right through and check that no pink remains inside mince or a thick cut. Freezing for several days also lowers the risk, but heat is more reliable.
- Leave cured and cold-smoked products alone for the duration of the pregnancy: salami, air-dried ham, dry sausage. This is the point most often missed.
- Wash vegetables, herbs and fruit thoroughly, with the aim of removing soil rather than dust.
- Wash hands, knife and board immediately after handling raw meat. Do not cut salad on that same board.
- Wear gloves for gardening and for houseplants, and wash your hands afterwards.
- Hand the litter tray over to someone else in the household. If there is nobody to do it, use gloves, wash your hands afterwards, and empty it every single day: what has just been passed is not yet infectious.
- Do not feed the cat raw meat, and where possible do not let it out to hunt.
- Avoid unpasteurised milk, goats' milk in particular, and water of unknown origin.
- Stay away from lambing and kidding, and do not handle newborn lambs.
If infection in pregnancy is suspected
It is checked with a blood test for antibodies. Interpreting the result yourself is next to impossible, and a single positive line is no reason to be frightened: most often it records an old encounter with the parasite, which is to say protection. The doctor looks at the combination of different antibody classes, at how the levels move over time, and, where needed, orders a further test that helps date the infection.
If recent infection is confirmed, there is something to be done about it, and that is the main reason testing makes sense at all. An antibiotic is started that lowers the chance of the infection reaching the baby. To find out whether it has crossed, the amniotic fluid is examined. If the foetus is infected, treatment is switched to a combination of medicines that acts on the parasite itself, taken until the end of the pregnancy, and after birth the baby is investigated and followed up, eye checks included, with treatment if it is needed.
Starting early makes a real difference to the outcome, so a suspicion means seeing a doctor now rather than waiting for the next routine appointment.
Weakened immunity: when waiting is not an option
This is the second group for whom toxoplasmosis genuinely is dangerous: people with HIV and a low CD4 lymphocyte count, people on chemotherapy, people taking immunosuppressants after an organ transplant, and people with certain blood disorders.
Here the danger comes less from a new infection than from the old one that has lain dormant for years: as immune control loosens, the parasite wakes up. The brain is what suffers most often.
If someone with weakened immunity develops any of the following, help is needed immediately — call an ambulance (in Spain, Italy, Portugal, Poland and Ukraine the single number is 112):
- a headache that builds day by day and does not yield to ordinary painkillers;
- confusion, mental slowing, changes in behaviour or speech;
- weakness or numbness in an arm or a leg, usually on one side;
- a seizure, particularly a first one;
- loss of balance and coordination, an unsteady walk;
- a temperature together with any of the above.
Separately, but also without delay: a sudden drop in vision, pain in the eye, or a dark patch in the field of view. In someone with weakened immunity that may be inflammation of the retina, and there it is a matter of days. Watching and waiting is not an option in either situation: treatment works well, but it has to start in time.
Online consultation
Most people arrive here holding a test result and asking what it means. In an online appointment the doctor will take the result apart by antibody class, say whether it points to an old encounter with the parasite or a recent infection, and whether the test should be repeated and after what interval. If you are planning a pregnancy, you can find out in advance whether you are protected and leave with a concrete list of everyday measures instead of a vague "be careful with the cat". What to do about the animal at home, and what to change in the kitchen, are discussed separately. If the picture suggests recent infection in pregnancy, you will be referred to an obstetrician without delay. Neurological signs in someone with weakened immunity are not for an online appointment: those are a reason to call an ambulance.
This material is for information only and does not replace medical advice.
Consult with a doctor about Toxoplasmosis
Discuss your symptoms and possible next steps with a doctor online.
Online doctors for Toxoplasmosis
Discuss your symptoms and possible next steps for Toxoplasmosis with a doctor online.
