Toxoplasmosis

Toxoplasmosis is a condition that results when a patient is infected by the Toxoplasma gondii parasite, it is a notable disease in Ireland. Toxoplasmosis is the most common cause of eye inflammation in the world. A patient is typically affected by Toxoplasmosis by consuming undercooked meat, mother-to-child transmission during pregnancy (congenital toxoplasmosis) or exposure to cat faeces that contain the Toxoplasma gondii parasite. Most patients who are infected with Toxoplasmosis do not show any symptoms of the disease, when symptoms are presented they typically are described as "flu-like" symptoms such as, fever, swollen lymph glands, headache, fatigue and body ache. Patients who suffer with underlying conditions such as HIV/AIDS or patients who have compromised immune systems are more at risk of developing Toxoplasmosis as their immune systems finds it difficult to fight the infection. The parasite which causes Toxoplasmosis (Toxoplasma gondii) has the ability to form microscopic cysts within muscle tissue and can harbour in the body for many years, in some cases it can reoccur.

Toxoplasmosis may affect the eye as it can attack the retina, leading to symptoms such as pain with eye movement, blurred vision, floaters and deterioration of vision, this is known as Ocular Toxoplasmosis. Ocular Toxoplasmosis can be identified by the use of OCT, common findings of the condition include increased reflectivity within the retina corresponding to the area of retinal inflammation along with shadowing of the underlying choroidal tissue. Posterior hyaloid (a branch of the ophthalmic artery) thickening, detachment over the lesion and contained abnormal hyperreflectivity are also common findings associated with Toxoplasmosis. Symptoms of Ocular Toxoplasmosis include pain in eye(s), photophobia (sensitivity to light), blurred vision and watery eyes. Ocular Toxoplasmosis can reoccur in the weeks and even years following initial infection, each time it reactivates it can cause extensive damage to the retina. If Ocular Toxoplasmosis affects central structures of the retina, it can eventually lead to blindness as there is more progressive vision loss in the patient.

Congenital Toxoplasmosis occurs when a woman becomes newly infected from the parasite Toxoplasm a gondii during or just previous to pregnancy, this can result in the infection being passed to the baby. Toxoplasmosis in a pregnant woman can lead to a miscarriage or the baby can be born with signs of Toxoplasmosis at birth such as abnormal enlargement or abnormal smallness of the head. In most cases, a baby infected with congenital toxoplasmosis may not show any symptoms at birth but may develop symptoms later on in their lifetime and these symptoms may lead to vision loss, seizures and cognitive problems.

Below is a comparison of a fundus photo of a normal retina (left) compared to a retina affected by congenital Toxoplasmosis (right), the retina affected by Toxoplasmosis demonstrates an isolated active lesion.