- Toxoplasmosis is an infection caused by a protozoon organism called Toxoplasma gondii. This organism is usually passed on to humans from cat feces. It can cause a variety of different symptoms depending on which part of the body is infected.
- Toxoplasma gondii is found throughout the world. How often it infects humans depends on which part of the world you live in, your lifestyle, and dietary habits. It is a parasite that usually lives in cats and is excreted in their feces. Humans become infected when they do not take appropriate precautions after handling cats or cat litter. Infection can also occur from eating contaminated soil, not washing the hands after handling infected soil, eating vegetables that have been contaminated by toxoplasma-containing soil, or by eating raw or undercooked meats contaminated with the organism. Also, pregnant women can pass the infection on to the fetus. Rarely, it can also be transmitted by contaminated blood.
- Once the organism enters the body, it may cause infection in many different parts of the body. These infections usually respond to treatment with antibiotics. In people with normal immune systems, the infection goes away on its own and does not cause further problems, even if untreated. In people with poor immune systems (as with AIDS or those getting chemotherapy), however, they may develop severe infections that are harder to treat. In the past, toxoplasmosis was not very frequently seen, but because of AIDS, it occurs much more frequently.
- The symptoms depend on which part of the body is infected. Most often, the initial infection may not cause any symptoms. In fact, 80% of those infected do not have any symptoms at all during the initial infection.
- Usually, if symptoms develop, they begin 1-2 weeks after infection.
- In most, a chronic infection follows the initial one. This means that the organism is still in the system, but does not cause any symptoms and does not require treatment.
- If for some reason, the individual's immune system is weakened, he may suffer an activation of the chronic (dormant) stage of the infection. In this case, he will no longer be able to suppress the disease and its symptoms, as in those with AIDS, those receiving chemotherapy, those on high doses of steroids, or those with inherited problems of the immune system.
- In those who do develop symptoms, the initial infection usually seems like a simple viral infection, with such typical symptoms as fever, chills, muscle and joint aches, fatigue, sore throat, headache, and sometimes a rash. Often, the lymph nodes in the neck become enlarged. Some may develop an enlarged liver or spleen.
- In a few rare cases, the patient may become much sicker, developing infection and inflammation of the lungs (pneumonitis), heart (myocarditis), liver (hepatitis), or the eyes (retinochoroiditis). Some may even develop infection and inflammation of the brain and spinal cord (meningoencephalitis). However, though extremely serious, this development is not very common.
- Most with normal immune systems will recover from the initial infection without treatment.
- Toxoplasmosis infection may be transmitted from mother to fetus. Therefore, it is extremely important that pregnant women not already immunized against the disease take full precautions to avoid infection (see below). Infection in the fetus is worse the earlier it occurs in term. Of all women infected with toxoplasmosis during pregnancy, only a small number have stillbirths or have to abort. If the mother does become infected, treating her will help decrease the chance of the fetus developing infection.
- Toxoplasmosis can also infect the eye. If the infection occurs during pregnancy, often the baby will be infected in both eyes. In neonates who become infected, usually only one eye is affected. Infections of the eye are rare in older children and adults. If it does occur, symptoms can range from Blurred Vision and blind spots, to glaucoma and total blindness in the affected eye.
- In those with weakened immune systems who have previously been exposed to toxoplasmosis, they are susceptible to a reactivation of the infection, which may affect the brain, eyes, or lungs, though any part of the body is vulnerable. Even without fresh infection, the original disease may activate and cause fever, Seizures, changes in mentation, headache, or neurological changes. This is a potentially serious problem in those with debilitated immune systems.
- The organism Toxoplasma gondii causes the infection.
- Symptoms, history, and physical examination help guide the doctor in diagnosing.
- However, the primary method of diagnosis is based on blood tests, culture results, or biopsy results.
- Biopsy means that a sample of tissue is obtained and then examined under microscope to see if the organism is present.
- Blood tests can be done to detect if the body is producing antibodies to the infection.
- Also, newer blood tests are available that detect the presence of the organism itself.
- A culture is obtained when lab technicians attempt to grow the organism from various body tissues.
- A CT scan or MRI scan can determine if there is any infection in the brain. However, one may still need a spinal tap to confirm.
- Other tests include chest X-Ray, Ultrasound of the heart, and biopsy of any organs or tissue suspected of hosting the organism.
- In those with weakened immune systems, they may not have a significant antibody response, making this test inconclusive. If so and infection is suspected, they may be treated without confirming infection, or they may require more advanced tests to confirm the presence of the organism.
- If infection is suspected in a pregnant woman, then Ultrasound of the fetus and/or amniocentesis is advised.
- Risk factors include inappropriate washing of hands after contact with raw meat, cats, cat litter, or soil infected with cat feces (or dog feces).
- Eating meat that has not been appropriately frozen and/or cooked.
- Children can get it from eating infected soil/sand.
- Eating vegetables that have not been appropriately cleaned and/or cooked.
- Occasionally, it can be transmitted through contaminated blood.
- Also, any process that decreases the effectiveness of the immune system can increase the risk of infection with the organism.
- The drug of choice is Pyrimethamine with either Trisulfapyrimidines or Sulfadiazine.
- Clindamycin is an alternative drug that has proven effective, especially for eye infections.
- Newer drugs are being studied to determine their effectiveness.
- In pregnant women, the drug of choice is Spiramycin. This drug is not used for other types of infection.
- Anyone on Pyrimethamine should take Folic Acid supplements because of medicine-induced Folic Acid deficiency.
- Not everyone infected needs to be treated.
- Individuals over 5 years of age with normal immune systems do not need to be treated unless symptoms develop.
- Once symptoms of the infection present, treatment will be required until they decrease and blood tests indicate the development of immunity to the disease. This usually takes about 3-4 weeks.
- Most eye infections heal by themselves. The best way to treat this type of infection is unclear. Seek the advice of a specialist.
- All with weakened immune systems who develop the infection need to be treated. Treatment is usually continued for 4-6 weeks after all symptoms have subsided. This may require treatment for several months. Successful treatment will need to be followed up with continued medication to prevent re-infection (prophylaxis)-until the immune system is back to normal. Those with AIDS, who will never have normal immune systems, will need to be on medicines for the rest of their lives to prevent repeat infections.
- Also, those with weakened immune systems who have evidence of past infection with Toxoplasmosis will need to be placed on medicines to prevent infection from ever occurring.
- Babies who were infected while they were in the uterus should also be treated after birth.
- Pregnant women who develop the infection need to be treated to reduce the chance of the fetus becoming infected.
- The long-term prognosis for infected individuals with normal immune systems is very good, and almost all make full recovery. Those with weakened immune systems usually do well if treated early-if left untreated, they will likely die from it.
- Seek medical attention as soon as possible.
- Prevention is the most important safeguard.
- The organism can be destroyed by freezing meats to below -20º C for 2 days, or by heating meat to at least 60º C for at least 4 minutes before consuming. All meats should be thoroughly cooked before eating.
- The organism can remain alive in cat feces for up to a year. However, for the first 48 hours it is not as infectious. Cat litter boxes should be cleaned every day.
- Also, every effort must be made to keep cats and dogs out of children's play areas and sandboxes. Children tend not to be conscientious about washing their hands after playing outdoors or in sand. They may even eat small amounts of sand or dirt, or put contaminated hands in their mouths. Therefore, it is very important to take this preventive step in order to try to avoid any infection. Parents and caretakers need to make every effort to have children wash their hands before eating or touching the mouth or face.
- Thoroughly wash your hands after cleaning the litter box. Also, wash your hands if you think that any soil you've touched might be contaminated with cat (or dog) feces. The basic rule is that it is always a good idea to frequently and thoroughly wash your hands.
- Indoor cats should be fed only dry, canned, or cooked meat.
- Pregnant women comprise a special risk group and must be extra careful to avoid spreading infection to the baby. The easiest and best way to avoid any problems is to stay away from cats and cat litter when pregnant.
- If this is not possible, pregnant women will need to have their blood tested to determine if they have developed immunity to the organism. The doctor can do the necessary blood tests.
- If a pregnant woman has developed some level of immunity, she will still need to be careful and follow the precautions listed here.
- If she has no immunity, then to be safe she must avoid all cats and cat litter. She will also need to thoroughly cook all meats, wash her hands after handling uncooked meat, before touching her face, and before eating.
- If she has no immunity but still has contact with cats or cat litter, then other precautionary measures (see above) need to be followed. In addition, she will need to have her blood checked periodically during pregnancy to make sure not to develop any infection.
- It is very important that pregnant women tell their doctors if they have any cats at home.
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