 Let's move on and talk about some protozoa that can affect the central nervous system. First and foremost is toxoplasmosis. This is caused by toxoplasma gondi. Toxoplasma gondi is transmitted through cysts and meat, which is our most common transmission, but we can also see it in cat feces. This is going to be a typical buzzword on the USMLE for pregnant females that could have become sick due to an infection caused by the cat. So we always tell pregnant females to stay away from cat litter throughout the course of their pregnancy. The symptoms of a toxoplasmosis infection are often asymptomatic or you can have flu-like symptoms in healthy individuals. Where our issue comes in are when we have immunocompromised patients. That is where we can find brain abscesses that will show ring-enhancing lesions on a CT scan. As we just mentioned, pregnancy is something to be aware of with a toxoplasmosis infection. Keep those pregnant women away from cat feces. To diagnose this, we use a serology or we can also do a biopsy and see a tachyzoite in the biopsy, as you see here on the left. The serology is going to show a high IgM or a rising IgM. To treat toxoplasmosis, we use a combination drug, sulfidazine and pyrimethamine. Our next protozoa that can affect the central nervous system is neglaria fallary. Neglaria fallary is unique because it only is found in warm freshwater lakes, ponds and streams. You will not see this in seawater that is salinated and you will not see it in cold lakes and ponds. So this is typically relegated to the southern portions of the United States where it is warm during the summer. Symptoms of a neglaria fallary infection include severe prefrontal headache, nausea, high fever and an altered sense of smell. The cyst form as you can see here on the right is the form that is found in the water to help it survive unfavorable conditions. Once the conditions in the water are favorable, it will break out of the cyst form and form the trophozoite form as you see here. The trophozoite form is the infectious form and this basically will infect humans by entering the nasal mucosa from someone swimming in these warm freshwater lakes and it grabs on to the olfactory nerve and it ascends into the brain. The reason this is very fatal and people that have this infection is because once the symptoms show up it is a very progressed disease and it progresses very fast. This is a rapidly fatal meningio encephalitis also known as primary amoebic meningio encephalitis. To diagnose this we're looking for modal amoebas in the spinal fluid so a spinal tap will show these modal biflagelate amoebas that you see here on the left side of that picture. Treatment is with amphotericin B. Those people that have been able to survive were treated very early on in their stage of disease with amphotericin B but it does usually leave some residual effects if they are able to survive. Finally, African sleeping sickness is caused by trapanosoma brusii. It is transmitted by the ctc fly which is a painful bite from the fly. The ctc fly bite injects trapanomastagotes into the bloodstream that then undergo replication inside the human body. Symptoms of African sleeping sickness include enlarged lymph nodes, a recurring fever, somnolence, and a coma so that is why we call it the sleeping sickness. To diagnose this we do a blood smear and you will see those trapanomastagotes in the blood smear. Treatment is with ceramin for an acute infection and if this is chronic we use melarsoparol. You can remember this with the mnemonic I sure am mellow when I'm sleeping. So sleeping sickness I sure sherman am mellow melarsoparol.