Toxoplasmosis is an infection caused by a parasite that infects cats and other animals. Here all you need to know, from causes to treatment.
This is a very common parasite all over the world, for which we will be discussing; what is the disease like? What causes the infection? And, which are its symptoms?
Furthermore, there will be an explanation about the diagnosis of the disease, its treatments, and ways to prevent it. For more information on this critical topic, continue ready to get the information directly from a doctor.
What is toxoplasmosis?
Toxoplasmosis is a disease caused by Toxoplasma gondii (T. gondii), a parasite that can affect both animals and humans.
Parasites are organisms that need a living host at some point in their life cycle to reproduce and get nutrients. Hosts can go from mammals like dogs, cats, humans, cows to mosquitoes, flies, snails, birds, and many others.
There are two types of parasites; helminthic, which are multicellular, for example, the ones that look like worms, and protozoan. The latter is unicellular, which means they are microscopic and can live inside or outside the host’s cells.
T. gondii is a protozoan parasite with two life cycles, one that occurs in cats and another in mammals. Cats are the natural or definitive host of the parasite; meanwhile, other animals are the intermediate host.
The cat ingests the toxoplasmosis parasite in a cyst form after eating other animals’ raw meat. In the cat’s gastrointestinal system, the cyst opens up, releasing numerous toxoplasma parasites that become zygotes. At that point, the zygotes spawn a capsule around them, becoming an oocyst that goes outside through the cat’s feces.
The oocyst is a resistant structure that acts as an egg, ready to free the sporozoites suitably. Subsequently, they divide again inside the oocyst and become sporozoites through a process called sporulation. Finally, the intermediate host (humans in this case) gets the parasite through different ways that will have an explanation further on.
Within the intermediate host, the sporozoite has two different forms, tachyzoites and bradyzoites. The first is the one that causes an acute infection, while the ladder causes a chronic infection. They can convert into the other form depending on the circumstance they are in. Both can be dangerous in certain groups of people, but most times, they don’t lead to consequences.
What are the causes of toxoplasmosis?
The cause of toxoplasmosis is T gondii; this is a parasite that typically infects animals, although in this case, it infects people. Yet, there are different pathways for this to happen.
In cats, it starts by eating another animal (a bird or mouse) that has a cyst in their tissue. This tissue cyst contains bradyzoites that the animal previously got by ingesting the sporulated oocyst from infected cat feces. The infection process works similarly for humans, but there are other ways they can get the parasite.
One of the main routes is ingesting the sporulated oocyst, but they can be in several places for humans to consume. One of these is water, specifically untreated water, which can come from supposedly functioning water cleaning plants in cities. The oocyst can travel through very small pores and resist being in the water for several months.
Humans can also get the infective oocysts by getting in contact directly with infected cat feces. This can happen when cleaning a cat litter or getting in touch with contaminated soil. Afterward, the patient touches their mouth or touches food, leading to the Toxoplasma gondii infection.
Humans can get the Toxoplasma parasite by eating raw meat or undercooked meat with a cyst. The toxoplasmosis cysts exist when an infection becomes chronic, usually the case for most living things with this parasite.
This happens because the immunological system is strong enough to defeat tachyzoites and forces them to become bradyzoites. These get into a cyst that can resist until an opportune time for becoming tachyzoites again, causing an acute infection.
When eating a cyst, it can free the parasites inside of it and infect the patient. Other two important causes for the infection are; through the amniotic fluid from the mother to the fetus and through a blood transfusion (although the last isn’t as common).
What is the risk of getting toxoplasmosis?
Everybody has the risk of getting the Toxoplasma parasite, but not everybody has the same risk of developing the disease. Having a weak immune system is a significant risk factor for having severe toxoplasmosis.
There’re various scenarios in which the immune system isn’t working as it should, like HIV, which can progress to AIDS. This is a condition where the patient has a very low white blood cell count, specifically lymphocytes. These cells are fundamental for the immune system’s proper functioning and, without them, AIDS patients are vulnerable.
AIDS patients can get the disease by a new infection they cannot fight back. They can also get it from cysts in their body from previous infection months to years prior. The bradyzoites within the cyst are liberated, turning into tachyzoites, which causes an acute infection. The cyst itself causes damage because of the faulty immune response that affects the surrounding tissue.
There are other kinds of patients with a high risk of developing toxoplasmosis because of a weak immune system. For example, patients that take steroids because of renal problems or have an organ transplant. This medication suppresses the immune system to prevent inflammation but leaves the door open for other infections.
Women have the risk of getting the disease while being pregnant, which can have terrible consequences on the child. The parasite Toxoplasma gondii can go from the blood of the mother to the fetus. Mothers who got the disease at least six months before getting pregnant are at risk of passing it down. Usually, it’s the first time the mother has contracted the disease for her to pass it. This is because she produces antibodies that can protect the child from the parasite if it’s an old infection.
What are the symptoms of toxoplasmosis?
Toxoplasmosis is an asymptomatic disease (without symptoms) in at least 90% of the patients that get the parasite. In most healthy people, when they get the parasite, the immune system controls the toxoplasma infection.
In this period, when acute toxoplasmosis occurs, the patients who aren’t asymptomatic can get various unspecific symptoms. The principal clinical sign that the patient shows is lymphadenopathy. This is ganglia’s growth, which looks like nodes under the skin not bigger than 3cm. They usually are not painful but may cause discomfort to the patient if they get many.
In the toxoplasmosis infection, the ganglia increased in size localize in the neck area or abdomen. When this happens in the abdomen, it can be painful, but it is hard for a doctor to precise if they are not very big. The patient presents flu-like symptoms such as fever, sore throat, muscle pain, fatigue.
In immunocompromised patients (people with a weakened immune system), the disease’s development is quite different. When a person has a weak immune system, it leaves them susceptible to infections of any type. Therefore, the patient will show clinical signs that are far worse than in people with a competent immune system.
For example, The patient can have brain damage symptoms like seizures, a changed mental state, headaches, balance loss, etc. This will depend on the severity of the damage and the places on the brain the damage occurs. There can also be symptoms involving the heart like palpitations or chest pain, and respiratory symptoms like shortness of breath or a dry cough. They also present ocular symptoms like vision loss and pain.
How are the toxoplasmosis symptoms in babies and newborns?
Newborns can suffer from many symptoms, especially from damage to the central nervous system. The first noticeable thing is the unnatural size of the head, whether it is smaller or bigger. There can also be bumps in the zones where the skull hasn’t completely closed yet since it closes months later.
Some very worrisome symptoms are seizures and a decreased muscle tone. This can be a bad forecast for the disease and the further development of the child. They also suffer from adult’s symptoms like lymphadenopathy, fever, and skin rashes. Growth in organs like the liver and the spleen can also happen in pediatric patients.
What complications are associated with this infection?
Depending on the patient, there will be different complications for toxoplasmosis. In immunocompromised patients, especially those with AIDS, we can find brain, heart, and lungs complications the most.
In the brain, the commonest one is toxoplasmic encephalitis, usually due to a previous infection’s reactivation. The harm to the brain because the inflammation and tissue damage can lead to permanent neurological problems. These have a relation to the area that the parasites infected and caused the inflammation. This complication will cause several signs and symptoms previously described.
The two other main diseases the patient can suffer as complications are myocarditis and pneumonitis. The first is an infection of the heart, precisely of the heart muscle, this being another common complication. The second is the inflammation of the lungs, in this case, caused by toxoplasma too. However, it usually doesn’t represent much trouble.
Congenital infection can be more complicated, as it will depend on the time it occurs. The fewer weeks the fetus has, the less chance it has of getting the disease. If it does get the disease, it is very severe. On the other hand, the more weeks the fetus has, the more the chance of getting the disease. If it gets the parasite, the least severe the infection will be. So, it will depend on when the infection happened throughout the nine months of pregnancy.
This fetal infection can be decisive for the baby’s life. When the disease happens young, the mother can even suffer from abortion due to the infection. There can also be a mental and physical delay depending on the seriousness of the baby’s brain damage. A congenital toxoplasmosis infection also can cause ocular toxoplasmosis. In this, the cyst deposits in the eye and later in life cause sight problems, even blindness.
How do you know if you have toxoplasmosis?
Doctors usually diagnose toxoplasmosis using serologic testing. These tests measure antibodies formed by our body in response to the infection or exposure to the parasite. The testing of Immunoglobulin G determines if the patient has been exposed at all to the parasite.
In case of needing to know if the infection is current, Immunoglobulin M shows an acute infection. This is important for pregnant women, so they know if the infection is while being pregnant or not. If your doctors have a strong suspicion and your result came negative, they could repeat the analysis later.
If the patient is pregnant and currently infected with toxoplasmosis, doctors can perform an amniocentesis. This can determine if the baby does have the disease or not. In this procedure, they use a fine needle to extract fluid from the amniotic sac where the fetus is. Then they examine the sample. Amniocentesis may pose a slight risk to the pregnancy since complications such as fluid loss or miscarriage can happen.
If there are severe symptoms like disorientation or seizures, it could mean you have encephalitis. In this case, the doctor will perform imaging tests, such as an MRI, to detect lesions in the brain. Less frequently, doctors can diagnose by direct observation of microorganisms in cerebrospinal fluid (CSF) or other tissue material.
There are some cases when doctors request a biopsy. In this procedure, a neurosurgeon takes small samples of brain tissue. A pathologist will then examine the samples under microcopy to see if you have cysts caused by toxoplasmosis.
What is the treatment for this infection?
This infection does not always require treatment. We have to remember that most healthy people with a competent immune system develop a minor disease without symptoms.
But there are patients, such as pregnant women or immunosuppressed that need medication. They usually need two medications, the combination of pyrimethamine and sulfadiazine. Pyrimethamine is a drug that doctors often use to treat other parasitic infections such as malaria. On the other hand, sulfadiazine is an antibiotic useful in treating and preventing a wide variety of infections.
Most of the time, patients with HIV or AIDS need to take this treatment for life to avoid reactivation of the infection. It is essential to know that pyrimethamine tends to reduce folic acid levels in our body. For this reason, the specialist may suggest you take some supplements while taking medicine.
In the case of pregnant women, the treatment may have some variations. Generally, the treatment will depend on how advanced the pregnancy is and, in this way, to reduce the fetus’s infection. In the first trimester and during the beginning of the second, a specialist may suggest an antibiotic called spiramycin. Later in the second trimester, they will recommend using the combination of pyrimethamine and sulfadiazine.
The use of these drugs has significant adverse effects on the mother and the fetus. For this reason, doctors use it under strict surveillance. Among the adverse effects, we can mention bone marrow suppression, which causes fewer blood cells production. An example of this suppression is anemia, a decrease in red blood cells, which carry oxygen.
How can you prevent toxoplasmosis?
According to the Centers for Disease Control and Prevention (CDC), there are many steps we can take to prevent infection with toxoplasmosis:
- It is recommendable always to wear gloves when working outdoors, and cover children’s sandboxes when not in use. Cats often use gardens and litter boxes as their own and deposit their feces in these.
- Hand washing is of utmost importance. Remember to wash your hands after being outside, before eating or cooking. And especially after touching cats, dirt, or raw meat.
- When cooking, we must wash and/or peel all fruits and vegetables before eating them. Avoid touching our eyes, mouth, or face when preparing food. They recommend using hot soapy water to clean countertops and items that have been in contact with raw meat.
- It is vital to avoid eating undercooked meat (especially pork, lamb, and venison). Remember cooking meat and poultry until they are no longer pink in the center or the juices run clear. Also, it is crucial to avoid the consumption of untreated water as well as unpasteurized milk and raw eggs.
If you have HIV / AIDS, or if you are a pregnant woman, or if you have a weak immune system, you should take some extra precautions.
- Avoid touching stray cats and keep yours indoors to reduce the risk of potential transmission of the parasite.
- When feeding your cats, the specialist recommends providing them with dry or canned cat food. We should remember cats can become infected by eating raw or undercooked meat too.
- Have someone else to care for your cats and change their litter box. If you have to change it yourself, remember to wear gloves while doing it. When you finish, wash your hands thoroughly with soap and warm water. Clean the litter box daily, and disinfect it with boiling water for at least 5 minutes.
Do you have symptoms, or are you at risk of this infection?
This tool is a Toxoplasmosis Symptoms Checker. It gathers the most important signs, symptoms, and risk factors for this infection. Therefore, this tool would tell anybody who uses it the likelihood of their symptoms because of toxoplasmosis. It will also tell if somebody has several risk factors or forms part of high-risk groups for the disease. Using it is free and would only take a few minutes.