Toxoplasmosis – Protozoa (CNS Infection)

00:00 Let’s talk briefly about the disease that's caused by toxoplasmosis. In most immunocompetent individuals, it is a mononucleosis-like syndrome. You feel tired, you may have a fever and you have no sense at all that this is toxoplasmosis. You probably won't seek medical care and the syndrome will go away, you will harbor the toxoplasma for the rest of your life and that will be the end of it. The real problem comes if you happen to be pregnant, and in your first trimester, and you get infected with toxoplasma. The toxoplasma parasites will go to the fetus. They will enter the fetus and replicate in it with severe consequences for the baby. They can infect many organs, including the eye, leading to chorioretinitis.

00:53 They can infect the brain and the baby will be born with severe brain defects such as hydrocephalus. It can cause cirrhosis of the infant’s liver or splenomegaly. So congenital infection is really what we must avoid, if you are just becoming pregnant or thinking about it. A good doctor will do a toxoplasma test to make sure that you're not infected.

01:20 If you are, if you show antibodies that means you were infected in the past, it means that you have cysts of the toxoplasma in you, but it's not likely that they will constitute a risk for the baby. If you are toxoplasma negative, your physician should tell you, avoid being infected, and if you are infected during pregnancy, this is a real problem, especially during the first trimester, and then you will have to decide whether you are going to take drugs or not to try and avoid infection of the fetus, because it's never a good idea to take drugs during pregnancy, they may harm the fetus in themselves.

01:58 So you can see why this is a serious issue. Now if you happen to harbor cysts, pseudocysts of toxoplasma and you become immunosuppressed, those cysts will produce active forms of the parasite, they will circulate throughout your system and they can infect the brain and the heart, and cause very serious disease. So pregnancy and immunosuppression are two conditions that we would like to avoid.

02:21 How do you diagnose toxoplasmosis? You can look for antibodies against the parasite.

02:27 This is something your physician will do right away or should do, should you become pregnant, or you can take biopsy specimens and look at them under a microscope and see the characteristic parasites which we saw at the beginning of our lecture.

02:43 How do you prevent toxoplasmosis? You should cook your meat very well of course, this goes without saying, many of us love a little bit rarity in our meat, but it's really from a health standpoint, not a good idea, toxo is only one of the many issues that can arise if you don't cook your meat well. Be careful cleaning your litter box. It's really a good idea to wear gloves and if you are pregnant, please let someone else do it. Do not do it yourself, because you're just risking get infected, because you don't know the status of your cat and it's not worth the risk on your fetus to clean the litter box. If you are infected and need treatment, there are some drugs that we have, but they are not without side effects. One combination is Pyrimethamine, which inhibits dihydrofolate reductase, an essential enzyme in the parasite, which we all also happen to have, so it's not without side effects, plus sulfadiazine or another combination, pyrimethamine plus clindamycin.