Chapter 31: protozoa Flashcards
What are the intestinal protozoa?
Entamoeba histolytica Giardia lamblia Crytosporidium Isospora Cyclospora
What is the sexually transmitted protozoan?
Trichomonas vaginalis
What are the meningitis causing amoebas?
Naegleria fowleri
acanthamoeba
Balamuthia mandrillaris
What are the main protozoan infections in AIDS patients?
Cryptosporidium
Isospora
Toxoplasma gondii
Pneumocystis carinii/jiroveci
What are the major differences seen between malaria and Babesiosis?
Most Babesiosis causes infection in stock animals like cattle not humans, though there are over 100 species.
Malaria is spread by mosquitoes while Babesia is spread by ticks.
Babesiosis does not affect liver cells
What are the blood-borne flagellates?
Leishmania and trypanosoma
What are psuedopodia and which organisms use them?
They are little feet-like projections used by amoeba that aid in the motility of the cells and the get food particles.
What are the two major forms of Entamoeba histolytica?
There is the mature cysts that is eaten and moved from one place to the other outside the host. While the motile feeding form is known as the trophozoite.
This is the active form of the amoeba that travels within the intestinal wall t eating bacteria and possible attacking the intestinal walls.
While a trophozoite, what special aggregation do amoebas form?
They have chromotoid bodies which are aggregates of ribosomes.
What does Entamoeba histolytica cause?
This amoeba can live harmoniously in the body or invade and erode the intestines causing abdominal pain, loose and bloody stools or bloody diarrhea.
If penetrates far enough it can travel to portal system and affect liver then spread to lungs = death.
What type of diarrhea is caused by Giardia lamblia?
Due to this organism coating the intestines blocking in take of fats, stool is smells horribly and is greasy and frothy in nature. Plus they are really gassy! Nasty!
How does crytosporidium diarrhea vary with immune ability?
Immunocompetent individuals have self-limiting diarrhea that has affected about 1/4 of the US population. On the other hand, immunocompromised individuals do not have the ability to rid their body of this organism and the diarrhea can be fatal due to extreme fluid loss.
Who are usually affected by trichomonas vaginalis and what symptoms do they exhibit?
Men and women can both be infected by males are generally asymptomatic.
Women will complain of itching and burning during urination. They will also have copious thin watery discharge from vaginal vault.
Which diarrhea causing protozoa require acid-fast staining to visualize from stool microscopy?
Isospora and clyclospora = which are mainly seen in immunocompromised patients
Naegleria fowleri present like most meningitis, what activity was the patient most likely participating in and how do you separate it from a bacterial meningitis?
The patient was most likely swimming in contaminated water and when jumping in the amoeba were launched into the cribiform plate and into the brain.
The CSF of this patient will have high neutrophil count, low glucose and high protein = same as bacterial meningitis but it will be void of all bacteria and have a motile amoeba instead.
Patient will also probably die much quicker = 1 week.
Acanthamoeba affect immunocompromised patients and present with what CSF signs and what symptoms?
The CSF will have acanthamoeba in the cyst and trophozoite stages creating headache, fevers, seizures, and focal neurological signs.
What are some defining characteristics of Balamuthia mandrillaris?
This is a viral meningitis that affects immunocompetent/compromised w/o being shot into the brain. It causes chronic granulomatous skin lesions w/ and w/o amoebic encephalitis.
Many people have been exposed to this and have no symptoms but once encephalitis sets in, most patients die from the disorder.
Toxoplasma gondii is most likely to infect or affect what two populations and what is the major sources of the organism?
Immunocompromised (AIDS patients) and pregnant women. This is because the protozoan can pass from mother to fetus and cause genetic defects.
The most common sources are from undercooked pork and cat feces and litter boxes.
What happens to the fetus w/ congenital toxoplasmosis?
The passing of toxoplasma gondii to a child is not good but depends on the infection of the mother. If infected early most births do not end well = abortion or still birth. If later in the pregnancy, the baby can be born but with different congenital defects. These include chorioretinits and blindness, seiaures, mental retardation, microcephaly, encephalitis and other defects.
Even if the baby is born healthy the person will most likely experience chorioretinites later in life.
MAIN EFFECTS = BRAIN AND EYES
Pneumocystitis carinii is known to affect almost every human on earth. What are the differences seen among the different populations effected?
Though this affects almost everyone, it is seen most often in either the very young which have either a very mild respiratory infection or completely asymptomatic. The other main population affected are the immunocompromised. This includes AIDS patients in which Pneumocystis carinii pneumonia is the most common opportunistic infection.
What is the approximate life cycle of malaria?
Plasmodium that causes malaria lives in two different organisms to and swap between the two dividing sexually and asexually.
Mosquitoes pass sporozoites to a human bloodstream the begin a pre-erythrocyte cycle.
The sporocytes invade the liver and ball up to form trophozoites.
These undergo asexual nuclear division producing a mass of nuclei call a schizont. The cytoplasm forms around each nuclei making merozoites which burst open the liver cell and pass into the blood stream.
While in the bloodstream the some will pass to another liver cell and others will invade erythocytes in the erythrocytic cycle. this follows the same asexual procedure to make more trophozoites while some merozoites form gametocytes.
These gametocytes can be taken back up in a mosquito leading to sexual division within the stomach.
This will lead to red cell lysis.
Which malaria species is the most common and deadly?
Plasmodium falciparum
What the is number one sign that malaria is possible?
cycles of chills, fever and drenching sweat caused by the simultaneous lysing of many erythrocytes.
What are the mechanisms of death in malaria?
The invaded erythrocytes that are cyclically bursting lead to anemia and causes sticky red blood cells that can plug up post-capillary venules. The blockages can stop blood delivery to kidneys, lungs, and brain. This can lead to renal failure, lung edema, and coma.
