Toxoplasma Gondii: Most 'Successful' Parasite In The World; Can Moms Pass This On To Babies?

What Is Toxoplasmosis?

It is estimated that 30 to 50 per cent of the world's population is infected with Toxoplasma - and infections may be increasing in Australia. According to studies conducted at blood banks and pregnancy clinics across the country during the 1970s, the infection rate was 30 per cent. However, a recent study in Western Australia found that 66 per cent of the population was infected [4].

For toxoplasma, cats are the primary host. Cats catch the parasite when they consume infected prey. Then, for a couple of weeks, they pass large numbers of parasites in their faeces in a form that can survive for long periods in the environment, even during extreme weather conditions [5].

When livestock consume faeces while grazing, parasites lodge in the muscle and remain after the animals are slaughtered for meat. Humans may become infected by consuming this meat, eating fresh produce, or drinking water contaminated by cats. It is also possible for a woman infected for the first time to pass the infection to her unborn child during pregnancy [6].

What Causes Toxoplasmosis?

Toxoplasma gondii (T. gondii) is a parasitic single-celled organism that can infect most mammals and birds. However, because T. gondii infectious organisms are excreted only in cat faeces, wild and domestic cats are the ultimate hosts of this parasite [7].

There is a high probability that cats that hunt or consume raw meat will harbour T. gondii. Therefore, it is recommended that you feed your pet cooked food or dry/wet cat food.

You cannot contract toxoplasmosis from an infected child or adult, but you may become infected in the following cases [8]:

• You come in contact with cat faeces that contain parasites. Suppose you touch your mouth after gardening, cleaning a litter box, or handling anything that has come into contact with infected cat faeces. In that case, you may accidentally inhale the parasites.
• Consuming contaminated food or water - lamb, pork, and venison are more likely to contain T. gondii.
• Cutting boards, knives, or other utensils that have been contaminated.
• Consuming unwashed fruits and vegetables.
• Transplants of infected organs or blood transfusions - in rare instances, toxoplasmosis can be transmitted through organ transplants or blood transfusions.
• If a person is infected with T. gondii, the parasite forms cysts that can affect any part of the body - most commonly the brain and muscle tissue of different organs, including the heart.
• As long as you are generally healthy, your immune system will keep parasites in check. As long as they remain dormant in your body, you are protected against re-infection with the parasite. However, if your immune system is weakened because of illness or certain medications, the infection may reactivate, causing serious complications.

What Are The Symptoms Of Toxoplasmosis?

Healthy individuals infected with toxoplasmosis may not show any symptoms and are unaware that they are ill. However, some people experience symptoms similar to those associated with the flu, as described below [9]:

• Aches and pains
• Swollen lymph nodes
• Headache
• Fever
• Fatigue

Symptoms of toxoplasmosis in people with weakened immune systems include:

• HIV/AIDS, chemotherapy or recent organ transplants may cause a previous toxoplasma infection to reactivate.

In such cases, you may develop more severe signs and symptoms of infection, such as [10]:

• Headache
• Confusion
• Impaired coordination
• Seizures
• There may be lung problems resembling tuberculosis or Pneumocystis jiroveci pneumonia, an opportunistic infection that occurs in people with AIDS
• Blurry vision caused by severe inflammation of the retina (ocular toxoplasmosis)

What Are The Risk Factors For Toxoplasmosis?

Anyone can contract toxoplasmosis. The parasite is widespread throughout the world. Toxoplasmosis infection may lead to serious health problems in the following situations [11]:

• You have HIV/AIDS
• You're undergoing chemotherapy
• You use steroids or other immunosuppressive medications

What Are The Complications Of Toxoplasmosis?

You are unlikely to experience complications from toxoplasmosis if you have a healthy immune system; however, otherwise, healthy people may occasionally develop eye infections. If left untreated, these infections can result in blindness [12].

However, if your immune system has been compromised due to HIV/AIDS, then toxoplasmosis can lead to seizures and life-threatening illnesses such as encephalitis. Children may develop disabling complications with congenital toxoplasmoses, such as hearing loss, mental disabilities, and blindness.

How Is Toxoplasmosis Diagnosed?

Toxoplasmosis is often difficult to diagnose without specific screening. Its symptoms are often similar to those associated with more common illnesses, such as influenza and mononucleosis [13].

If you are pregnant and have a current infection with toxoplasmosis, you must determine if your baby is also infected. Your doctor may recommend the following tests:

• Amniocentesis
• Ultrasound scan

If you have developed a life-threatening illness such as encephalitis, you may need one or more imaging tests to detect lesions or cysts in the brain. Among these tests are:

• Magnetic resonance imaging (MRI)
• Brain biopsy

How Is Toxoplasmosis Treated?

• For patients with HIV/AIDS, the treatment of toxoplasmosis is also pyrimethamine and sulfadiazine, along with folinic acid. The alternative is pyrimethamine combined with clindamycin.
• You may experience different treatment options if you are pregnant and infected with toxoplasmosis.
• If the infection occurred before the 16th week of pregnancy, you might be prescribed spiramycin. This drug may reduce your baby's risk of neurological problems related to congenital toxoplasmosis.
• After the 16th week of pregnancy, or if tests reveal that your unborn child has toxoplasmosis, you may be given pyrimethamine, sulfadiazine (leucovorin) and folinic acid (leucovorin).
• In the event that your infant has toxoplasmosis or is at risk of contracting it, pyrimethamine, sulfadiazine, and folinic acid (leucovorin) should be administered [14].

Can You Prevent Toxoplasmosis?

Several precautions can help prevent toxoplasmosis [15]:

• You should wear gloves whenever you work outdoors and wash your hands thoroughly afterwards with soap and water.
• Do not consume raw or undercooked meat.
• Clean kitchen utensils thoroughly.
• After handling raw meat, wash your hands thoroughly.
• Wash produces thoroughly. Remove peels whenever possible, but only after washing.
• Do not consume unpasteurised milk.

Health Benefits Of Adopting A Pet; Especially For Kids And The Elderly

For people with pets:

Pregnant women and other persons at risk for toxoplasmosis or its complications should take the following precautions:

• You should keep your cat indoors and feed it dry or canned food, not raw meat.
• If you come across stray cats or kittens, you should take them to the veterinarian before bringing them home, especially if you have pets.
• Wear gloves and a face mask when changing the litter, and wash your hands thoroughly. Ensure that the litter is changed daily to prevent excreted cysts from becoming infected.

Symptoms Of Toxoplasmosis In Babies: Can Mothers Pass It On?

Even if you do not experience symptoms yourself, if you are infected for the first time before or during your pregnancy, you can pass on the infection to your baby (congenital toxoplasmosis) [16].

• Your baby is at the greatest risk of contracting toxoplasmosis if you become infected during the third trimester and least at risk if you become infected during the first trimester. However, the earlier in your pregnancy the infection occurs, the more serious the outcome for your unborn child may be.

Many early infections result in stillbirth or miscarriage. Infants who survive are more likely to be born with serious problems, such as the following [17]:

• Seizures
• Having an enlarged liver and spleen
• Yellowing of the skin or whites of the eyes (jaundice)
• Severe eye infections
• Most babies with toxoplasmosis do not show any signs of the disease at birth. In many cases, infected infants and young children don't exhibit any signs until their teens or later, including hearing loss, mental disabilities, or eye infections.