Protozoa
- Trophozoites cause pathology
- Cysts are transmissible
Intestinal
Ø Amebae
- Entamoeba histolytica- causes amebic dysentary; can invade tissue; intestinal lumen habitat; can cause ectopic lesions; If in lumen, diiodoydroxyquinoline; if invasive, Flagyl (Metronidazole)
- Entamoeba coli
- Entamoeba nana
- Iodamoeba butchlii
- Dientamoeba fragilis
Ø Ciliates
- Balantidium coli- balantidiasis; can invade tissue; intestinal lumen habitat; tetracycline and Diiodohydroxyquinoline
Ø Flagellates
- Giardia lamblia- giardiasis; small intestinal lumen habitat; Flagyl (metronidazole)
- Chilomastix mesnili
- Trichomonas haminis
Ø Coccidia
- Cryptosporidium sp.- cryptosporidiosis; intestinal lumen habitat; X5; no treatment
- Cyclospora- cyslosporiasis; intestinal lumen habitat; trimethoprim & sulfa
Ø All of the above intestinal protozoa are: 1. transmitted in contaminated food or water in the cyst or oocyst (crypto and cyclo) stage 2. Diagnosed upon fecal examination
Extra-intestinal
Ø Plasmodium (malaria-causing)
- Plasmodium vivax- tertian malaria; species that cause relapse due to hypnozoites.
- P. malariae- quartan malaria
- P. faciparum- malignant tertian malaria
- P. ovale- rarest form
Ø All of the above plasmodium are 1. transmitted mosquito-human-mosquito with sporozoites 2. diagnosed by blood smear by ID of stages
Ø If in acute stage, treat with Chloroquine; If relapse- Primaquine; if resistant (P. falciparum) treat with Pyrimethamine + Sulfa
Ø Cause:
1. paroxysms (fever, chills, sweating) due to rbc destruction by schizonts
2. Spleenomegaly and Hepatomegaly due to inc. activity of phagocytes
3. Organ failure (urine usu. becomes filled with blood Þ renal failure also known as Blackwater fever)
4. Relapse is cause by hypnozoites in P. vivax infections.
Ø First the sporozoites infect hepatocytes and when they rupture, merozoites are released which then infect RBCs and the hypnozoites stay behind in the hepatocyte (P. vivax). The RBCs form trophozoites which then mature in the RBC to form Schizonts which then rupture the RBC.
Ø This release of parasites and debris stimulates the RE system which leads to hepattomegaly and spleenomegaly
Ø Anemia causes anoxia which causes necrosis which leads to damage & malfunctioning of various organs
Ø Toxoplasma gondii
- Feline hosts
- toxoplasmosis
- Transmission: through ingestion of oocysts
- Treatment: Pyrimethamine + Sulfa
Ø If congenital- infection of fetus is through tachyzoite which leads to multiple organ malfunction
Ø If postnatal- infection through ingestion of pseudocyst from infected meat or cat feces.; can have acute flu-like symptoms or chronic ocular problems; if immunodeficient, severe symptoms
Ø DIAGNOSIS: Morphology of tachyzoite or pseudocyst; serology
Ø Pneumocystis carinii
- pneumocystis pneumonia
- unknown transmission
- Interstitial plasma cell pneumonia
- DIAGNOSIS: biopsy with spec. stains to reveal uninucleate forms or cyst forms.
- TREATMENT: Trimethoprim + Sulfa
Ø Trichomonas vaginalis
- ONLY SEX. TRANSMISSIBLE PARASITE OF HUMAN
- Diagnosis: microscopic ID of trophozoite in vaginal smear
- TREATMENT: Flagyl (metronidazole)
Ø Naegleria spp.
- Causes purulent menigitis
- ameboflagellate
- TRANSMISSION: nasal
- DIAGNOSIS: by pathologist post-mortem
- TREATMENT: none
Tags: amebae, ameboflagellate, Balantidium coli, Blackwater fever, Ciliates, Coccidia, Dientamoeba fragilis, Flagellates, Iodamoeba butchlii, menigitis, Naegleria, paroxysms, phagocytes, Pneumocystis carinii, toxoplasmosis, Trichomonas vaginalis
