Toxoplasmosis is a parasitic disease caused by a parasite known as toxoplasma gondii and is amongst the many causes of deafblindness in the UK. This parasite infects many warm-blooded animals but it’s primary hosts are usually cats. The parasite forms cysts, which are closed sacs surrounded by a hard membrane and passed in the droppings of it’s host. In the UK cats can contaminate gardens and vegetables with the parasite even though they usually bury their faeces. So it’s fairly easy for humans to come into contact with the parasite.
The transmission of the parasites can occur in several ways. The most prevalent way in which humans contract the parasites are through ingesting contaminated cat faeces. This can occur with hand-to-mouth contact following gardening, cleaning a cats litter box or contact with sandpits. The parasites can also be transferred through ingesting raw or partially cooked meat especially lamb, pork or venison which contain Toxoplasma cysts. Similarly, the cysts can also be ingested via hand-to-mouth contact after handling uncooked meat or using utensils or cutting boards which have been contaminated by raw meat. The parasites can also be transferred through drinking contaminated water or from receiving an infected organ transplant or blood transfusion, although this is fairly rare.
Fortunately, the resulting infection is usually quite mild. It can present itself in a similar way to a glandular illness or produce symptoms like those produced by a mild flu. However, the most serious danger presented by the disease is to unborn children. If a pregnant woman contracts the infection early on in the pregnancy then there is a high risk that the disease will cause a congenic abnormality in the unborn child. It’s thought that around ten per cent of the unborn children who contract the disease will be seriously affected. And the earlier the disease is caught during pregnancy, the greater the risk of severe damage if it crosses the placenta to reach the foetus. Luckily, as the pregnancy progresses, the risk of serious damage to the foetus lessen. There isn’t widespread screening for the disease in the UK as the disease isn’t as prevalent as in other countries. And It’s thought that the disease only effects around 500 babies per year in the UK.
If the foetus is exposed to the disease early on then the child may be born with congenital toxoplasmosis and can develop several severe symptoms. Hydrocephalus, a calcification occuring in the brain and chorioretinitis, which causes damage to the retina are amongst possible affects. Deafness and epilepsy can also occur and the disease can cause eye problems to develop in later life.
Most adults who contract toxoplasmosis manage to recover quickly, without any treatment whatsoever. However in some cases the disease can be treated with sulpha drugs. Treating eye problems which result due to a toxoplasma infection can be much more complex. Similarly, treating pregnant women can also be complicated as they must be given alternative drugs due to the traditionally used ones being too toxic. Currently, no treatment can eradicate all cysts. This means that even though an infection may appear to be cured it may be reactivated at a later stage.