Toxoplasmosis

What is Toxoplasmosis?

Toxoplasmosis is an illness caused by a parasite called Toxoplasma gondii, which is a tiny organism that lives inside cells. This parasite infects a lot of people around the world, but the disease itself is rare because most people don’t show any symptoms. However, the parasite can cause serious illnesses in babies and people with weakened immune systems, either as a new infection or by reactivating an old, hidden one.

People often get toxoplasmosis by eating undercooked or raw meat that has the parasite, or by eating food or drinking water that’s contaminated. It can also be passed from a pregnant woman to her baby, or through organ transplants.

Anyone with a weakened immune system and all patients with serious symptoms of toxoplasmosis should receive treatment. The preferred treatment plan usually involves two medicines called pyrimethamine and sulfadiazine.

What Causes Toxoplasmosis?

T. gondii is a type of parasite that can only live and grow inside the bodies of warm-blooded animals, including humans. For this parasite to complete its life cycle, it needs a ‘home-base’ animal, that is a type of feline, and an ‘intermediate’ animal host. Cats can catch this parasite if they eat infected cysts or tiny eggs, often found in other hosts that they might eat. Once a cat is infected, it can pass on millions of these eggs through its poop for about 1 to 3 weeks. These eggs need about 1 to 5 days to turn into a form that can actually infect other animals and can stay in the environment in this form for about a year.

People might accidentally eat this parasite if they consume meat or other food that hasn’t been fully cooked and is contaminated with the infected cat’s feces. The gastric fluid in the person’s stomach will break down the cyst’s wall and release the parasites inside, which are called sporozoites and bradyzoites. These then enter the gut lining and transform into tachyzoites. Tachyzoites are another form of T. gondii, which multiply quickly.

Tachyzoites can enter any cell with a nucleus, which includes cells like dendritic cells, monocytes (a type of white blood cell), and neutrophils (another type of white blood cell); this can help the parasite spread. However, once the body’s immune system starts to fight back, these tachyzoites slow down their growth and eventually turn into bradyzoites. Bradyzoites surround themselves with a thick wall, forming a cyst that contains thousands of bradyzoites. These cysts can lie dormant within a person unless the person’s immunity weakens, at which point they could become active again.

A human can get a T. gondii infection in four different ways:

1. Foodborne transmission: this happens if you eat undercooked or raw meat that contains the cysts.
2. Zoonotic transmission: this happens if you eat food or water that’s contaminated with feces from an infected cat.
3. Vertical transmission: this happens if a pregnant woman has an infection, which could then spread to her baby through the placenta.
4. Transmission through organ transplants or blood transfusions: this might happen if the donor was infected with T. gondii.

Risk Factors and Frequency for Toxoplasmosis

The Centers for Disease Control and Prevention (CDC) reports that over 11% of the US population over the age of 6 is infected with a parasite called T. gondii. This parasite causes toxoplasmosis, which is the leading cause of death from foodborne infections. Toxoplasmosis is one of five neglected parasitic infections in the US, alongside Chagas disease, trichomoniasis, toxocariasis, and cysticercosis.

The number of people infected varies across different countries and even within different regions of the same country. The factors that can affect this include:

Warm and humid areas have a high number of cases, as the parasite survives better in these conditions.
Areas with livestock can increase the risk of infection, as the animals may carry the parasite.
The chance of being infected increases as people get older.

Individuals with human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS) have the same risk factors as the general population. However, those with AIDS have a greater risk of the disease becoming more severe when their CD4 count, a type of white blood cell, drops below 100 cells per microliter of blood.

Signs and Symptoms of Toxoplasmosis

Infection with T. gondii, a type of parasite, often doesn’t cause any symptoms. Some individuals with a healthy immune system might experience mild symptoms such as fever, chills, headache, throat pain, muscle aches, rash, or enlarged liver or spleen. It’s also common for these individuals to report painless swelling in the neck that lingers for several weeks. If someone comes in with fever and swollen neck glands, doctors should consider the possibility of toxoplasmosis.

People with weakened immune systems (e.g. due to HIV) are more susceptible to serious complications. These people typically come in with neurological symptoms, though it’s not uncommon for other body parts to be involved.

Cerebral toxoplasmosis: Depending on the specific brain region affected and the number of lesions, symptoms can range from fever, seizures, headache, vision changes, altered thinking, neurological problems, cognitive dysfunction, unsteady movements, and involuntary movements.
Extracerebral toxoplasmosis: This usually manifests as lung inflammation (pneumonitis) and eye inflammation (chorioretinitis), but it can also affect the heart, digestive tract, genital and urinary systems, muscles, or it can be widespread.
- Pneumonitis: Patients usually come in with fever, cough, and difficulties breathing.
- Chorioretinitis: Symptoms can include vision changes, floaters (specks appearing to float in your field of vision), and eye pain.

Testing for Toxoplasmosis

While a biopsy (a medical test involving sample of cells or tissues) can confirm the diagnosis, you can also be diagnosed with toxoplasmosis (an infection caused by a parasite) through non-invasive methods, including labs and imaging techniques.

* Blood tests: These are typically the primary way to determine if you have a toxoplasmosis infection. This involves identifying two types of antibodies, the warriors in your body that fight infections, IgM and IgG. IgM antibodies usually appear about 5 days after infection and peak in 1 to 2 months, while IgG antibodies can be seen after 1 to 2 weeks, and reach their highest levels in 3 to 6 months. Test results can be difficult to interpret, though, as the test for IgM antibodies is not specific, so may react to other infections as well.

* Molecular testing: This is another way to diagnose toxoplasmosis. With this test, the DNA of the Toxoplasma parasite can be detected in your blood and other body fluids.

In terms of imaging tests, computed tomography (often known as a CT scan) or magnetic resonance imaging (MRI) can be done. These scans show numerous areas with ring-shaped lesions in your brain, a sign of toxoplasmosis. In the early stages, the changes due to inflammation are minimal and may not be clearly shown on a CT scan. Hence, MRI scans are usually preferred over CT scans to diagnose brain lesions due to toxoplasmosis. For precise diagnosis and to rule out other medical conditions, highly specific scans like Single-photon emission CT or PET scans can be done.

Biopsy is another technique to confirm the diagnosis by spotting tachyzoites and tissue cysts of Toxoplasma in tissue samples. This procedure isn’t usually carried out unless you don’t show any signs of improvement on tests or with symptoms within 14 days of starting treatment.

Treatment Options for Toxoplasmosis

The aim of treatment is to control the growth of the parasite during an active infection. Treatment would usually be prescribed for healthy individuals with serious or long-lasting symptoms, and is always given to patients with weakened immune systems.

If your doctor suspects you’ve been infected with the T. gondii parasite, they’ll start you on treatment based on their initial diagnosis, rather than waiting for test results. Usually, a combination of the medications pyrimethamine and sulfadiazine is used. Treatment will continue for about six weeks, after which you’ll stay on a maintenance dose of these medications for a longer period.

To guard against the side effect of folic acid deficiency from the sulfadiazine medicine, folic acid is also included in the treatment plan. Patients with brain swelling or eye infections from toxoplasmosis may also be given steroids.

Along with the anti-toxoplasmosis medication, if you have HIV, your doctor might begin antiretroviral therapy. This therapy boosts your immune system and is often started about two weeks after the anti-toxoplasmosis treatment begins.

The risk of getting toxoplasmosis is especially high if you have HIV/AIDS, and if your blood tests reveal you have antibodies for T. gondii and your CD4 cell counts are less than 100 cells/microL. The CD4 cells are a type of white blood cell that fights against infection. Preventative anti-toxoplasmosis therapy is then begun. The medicine of choice to prevent reactivation of a latent infection is Trimethoprim-sulfamethoxazole. Once your CD4 count rises to more than 200 cells/microL for at least three months and your viral load decreases, you can stop taking this preventative medication.

The conditions that can be mistaken for each other due to their similar symptoms include:

CNS lymphoma (a type of cancer in the brain)
Metastatic brain lesions (cancerous spots that have spread to the brain from other parts of the body)
Progressive multifocal encephalopathy (a rare and serious brain disease)
Cerebral tuberculosis (a form of TB that affects the brain)
Bacterial/fungal brain abscess (an infection causing a pocket of pus in the brain)
Cytomegalovirus (a common virus that can cause disease in people with weak immune systems)
Acute HIV infection (early stage of the HIV virus)
Herpes simplex encephalitis (a rare, but serious condition where the brain gets inflamed due to the herpes virus)

What to expect with Toxoplasmosis

Acute toxoplasmosis, a type of infection, usually resolves on its own in people with a healthy immune system, without any long-lasting effects. Detecting this infection early and starting treatment promptly, particularly in individuals with AIDS, can improve recovery chances in those with weakened immune systems.

Possible Complications When Diagnosed with Toxoplasmosis

Toxoplasmosis is a condition that can lead to serious, potentially fatal complications in people with weakened immune systems. These complications can present themselves as brain inflammation or toxoplasmosis manifesting in areas outside of the brain. Starting treatment can sometimes lead to a situation known as the immune reconstitution inflammatory syndrome (IRIS). This syndrome can result in a sudden worsening of symptoms. The treatment usually includes continuing with the medications to treat the infection, HIV medications, and either beginning corticosteroid treatment or increasing the dose if the patient is already on these drugs.

Common Steps in Treatment:

Continuing anti-infective medication
Administration of antiretroviral therapy
Initiating corticosteroids or increasing the dosage if already in use

Preventing Toxoplasmosis

In certain parts of the world, it has been found that the risk of getting infected with toxoplasma, a kind of parasite, can be as high as 60%. Even though the initial infection can go away on its own, there’s a chance for the disease to become severe if the dormant parasite gets reactivated. People can take the following steps to reduce their chances of getting infected:

Cook your food properly until it reaches safe temperatures, or freeze meats for several days at extremely low temperatures before cooking.
Always make sure to wash all fruits and vegetables thoroughly or peel them.
Clean surfaces thoroughly after they’ve been in contact with raw meat, poultry, seafood, and unwashed fruits or vegetables.
Try to avoid drinking goat’s milk that hasn’t been pasteurized. Pasteurization is a process that kills harmful bacteria.
After touching litter boxes or any sand or soil that might have been in contact with cat feces, wear gloves and wash your hands properly.

Frequently asked questions

Acute toxoplasmosis usually resolves on its own in people with a healthy immune system, without any long-lasting effects. However, individuals with weakened immune systems, such as those with AIDS, have a greater risk of the disease becoming more severe. Detecting the infection early and starting treatment promptly can improve recovery chances in those with weakened immune systems.

Toxoplasmosis can be acquired through foodborne transmission, zoonotic transmission, vertical transmission, or transmission through organ transplants or blood transfusions.

Signs and symptoms of Toxoplasmosis can vary depending on the individual's immune system and the specific body part affected. Here are the signs and symptoms associated with Toxoplasmosis: 1. Mild symptoms (in individuals with a healthy immune system): - Fever - Chills - Headache - Throat pain - Muscle aches - Rash - Enlarged liver or spleen - Painless swelling in the neck that lingers for several weeks 2. Neurological symptoms (in individuals with weakened immune systems): - Cerebral toxoplasmosis: - Fever - Seizures - Headache - Vision changes - Altered thinking - Neurological problems - Cognitive dysfunction - Unsteady movements - Involuntary movements 3. Extracerebral toxoplasmosis: - Lung inflammation (pneumonitis): - Fever - Cough - Difficulties breathing - Eye inflammation (chorioretinitis): - Vision changes - Floaters (specks appearing to float in your field of vision) - Eye pain It's important to note that some individuals with Toxoplasmosis may not experience any symptoms at all. If someone presents with fever and swollen neck glands, doctors should consider the possibility of toxoplasmosis. Additionally, people with weakened immune systems, such as those with HIV, are more susceptible to serious complications from Toxoplasmosis.

The types of tests that are needed for Toxoplasmosis include: - Blood tests: These tests identify the presence of antibodies (IgM and IgG) that fight infections. IgM antibodies appear about 5 days after infection, while IgG antibodies can be seen after 1 to 2 weeks. Blood tests can be difficult to interpret, as the test for IgM antibodies is not specific. - Molecular testing: This test detects the DNA of the Toxoplasma parasite in blood and other body fluids. - Imaging tests: Computed tomography (CT) scans or magnetic resonance imaging (MRI) can show ring-shaped lesions in the brain, which are a sign of toxoplasmosis. MRI scans are usually preferred over CT scans for diagnosing brain lesions due to toxoplasmosis. - Biopsy: This technique confirms the diagnosis by spotting tachyzoites and tissue cysts of Toxoplasma in tissue samples. Biopsy is usually done if there are no signs of improvement on tests or symptoms within 14 days of starting treatment.

The conditions that a doctor needs to rule out when diagnosing Toxoplasmosis include: - CNS lymphoma (a type of cancer in the brain) - Metastatic brain lesions (cancerous spots that have spread to the brain from other parts of the body) - Progressive multifocal encephalopathy (a rare and serious brain disease) - Cerebral tuberculosis (a form of TB that affects the brain) - Bacterial/fungal brain abscess (an infection causing a pocket of pus in the brain) - Cytomegalovirus (a common virus that can cause disease in people with weak immune systems) - Acute HIV infection (early stage of the HIV virus) - Herpes simplex encephalitis (a rare, but serious condition where the brain gets inflamed due to the herpes virus)

When treating Toxoplasmosis, there are potential side effects that may occur. These include: - Folic acid deficiency from the sulfadiazine medication - Immune reconstitution inflammatory syndrome (IRIS), which can result in a sudden worsening of symptoms. This may require corticosteroid treatment or an increase in dosage if the patient is already on these drugs.

You should see an infectious disease specialist for Toxoplasmosis.

Over 11% of the US population over the age of 6 is infected with a parasite called T. gondii, which causes toxoplasmosis.

Toxoplasmosis is treated by controlling the growth of the parasite during an active infection. Treatment typically involves a combination of the medications pyrimethamine and sulfadiazine, which are taken for about six weeks. After this initial treatment period, a maintenance dose of these medications is continued for a longer period. Folic acid is also included in the treatment plan to guard against the side effect of folic acid deficiency from sulfadiazine. In cases where there is brain swelling or eye infections, steroids may be given. Additionally, if the patient has HIV, antiretroviral therapy may be started about two weeks after the anti-toxoplasmosis treatment begins to boost the immune system.

Toxoplasmosis is an illness caused by a parasite called Toxoplasma gondii, which is a tiny organism that lives inside cells.