Toxoplasmosis Gondii

What is Toxoplasmosis Gondii?

T.Gondii is a parasite that was first identified as a human pathogen in 1939. It can infect all warm blooded mammals like birds, rats, cats and humans. Cats are what experts call the “definitive host” because it’s the only mammal in which the parasite can complete its life cycle and infect other mammals. A cat is infected through contact with other cats and their feces or by eating any rodents (mice, rats, etc) who excrete potentially infectious oocysts (eggs). Worryingly, most cats infected with T. gondii show no symptoms, so knowing whether your animal is affected is difficult.

How Can I get It?

There are various ways the parasite can be transferred from cats to humans, with the most common being through the faecal contamination of hands i.e. emptying the cat’s litter tray or handling infected soil without wearing gloves. Consuming contaminated meat, especially lamb and veal, coming into contact with raw meat and then touching your mouth or using contaminated utensils, are other known ways to transmit the parasite.  If you eat unwashed fruit or vegetables that have come from infected soil, you also increase your risk of disease.

How Can I Stay Safe?

You can stay safe by reducing exposure to this parasite:

-Avoid cleaning the litter -wear gloves

-Get the litter box cleaned daily as T.Gondii doesn’t become infectious until about 1-5 days after it’s shed in cat faeces.

-Avoid eating undercooked or raw meat

-Wear gloves when gardening

-Keep cats indoors – this helps in preventing them from eating rodents (which are carriers of this parasite)

Worryingly, most cats infected with T. gondii show no symptoms, so knowing whether your animal is afflicted is difficult. Humans with contracted T. gondii will probably show no symptoms either.  Often they will experience mild flu-like symptoms, including : Body aches, Swollen lymph nodes, Headache, Fatigue sore throat, and a slightly raised temperature.

Congenital Toxoplasmosis is a more serious condition and occurs when a woman becomes infected during pregnancy and passes the infection on to her unborn baby. This can result in the baby developing serious health problems such as blindness and brain damage. Ocular lesions have been seen in young children with congenital Toxoplasmosis, often leading to blindness in one or both eyes. A child’s immune system takes a year to fully develop ,so it is especially vulnerable to parasitic infection before this stage. Left untreated, Toxoplasmosis can have severe implications for both infants and adults.

Often, infected children don’t develop signs and symptoms such as hearing loss, mental disability or serious eye infections until their teens or later.  The link between Toxoplasmosis infection and neurological disorders and psychosis is only recent, but it is well supported.  Studies are reviewing the effect of the disease on Dopamine and it’s manifestations on conditions such as ADHD (Attention Deficit Hyperactivity Disorder), OCD (Obsessive Compulsive Disorder) and Schizophrenia.

As yet, there is nothing to suggest that households with multiple cats are at greater risk of Toxoplasmosis. The term ‘Crazy Cat Lady’ was actually coined to refer to the various behavioural and psychological disorders associated with the human contraction of T. gondii found in cats, yet there is no hard evidence to indicate people with more cats have a higher rate of infection.

Ocular toxoplasmosis T. gondii can lie dormant (inactive) in the retina for many years. But if the parasite becomes active again, it can start a new infection. Ocular toxoplasmosis causes ocular lesions, which are wounds in the eyes caused by inflammation and scarring.     They lesion can either appear in either the Retina-the light-sensitive layer of tissue at the back of the eye  or the Choroid– the layer behind the retina that contains major blood vessels  This damage to the eyes is called Retinochoroiditis and can cause eye problems such as:

-Partial loss of eyesight in one eye

-Squint, where one eye looks in a slightly different direction to the other one

-Cataracts, a clouding of the eye’s lens

-Microphthalmia, eye shrinking –                                                                                                                                                                              –

-Optic atrophy, a loss of cells and tissue from the optic nerve, which connects the eye to the brain, resulting in poor vision.

Antibiotics and steroids are often used to treat the lesions. The scarring caused by toxoplasmosis will not clear up, but treatment may prevent it from getting worse.

Regular eye tests may help detect any abnormalities as they develop, and treatment with antibiotics can limit damage toxoplasmosis causes. However, at present it’s not possible to reverse damage already done.

Resources:

Jack S. Remington, M.D., from the Department of Immunology and Infectious Diseases, Research Institute of the Palo Alto Medical Foundation.
Nhs.uk             
Pamf.org
Mayo.org.uk                                                                                                                                                                                       http://theeinsidepoop.com/pregnant-women-and-cats-with-toxoplasmosis/?