Parasites Flashcards
Parasitism
An association beneficial to one partner and harmful to the host
Definitive host
Harbors the adult or sexually mature stages of the parasite’s life cycle
Intermediate host
Harbors the larval or sexually immature form of the parasite (or asexual development)
Reservoir
An infected animal serving as a source from which other animals can become infected
Vector
A living carrier that transport the parasite from infected to non infected host
Trophozoite
metabolically active
Cyst
non motile, protected by a membrane. Infective, dormant.
What invasive amoeba infects 10% of the world and causes colitis and ulcer formation?
Entamoeba histolytic (protozoa is an intestinally invasive protozoa that infects 10% of the world’s population in tropical, unsansitized regions.
How is Entamoeba histolytica spread and symptoms
Spread from fecal/oral cysts that develop from trophozoites in feces found in water (cysts can survive in water). NOT caused by undercooked meat. Symptoms: abdominal pain, mucus/bloody stool, tear drop ulcers, RUQ pain, can rupture
What do you treat Entamoeba histolytica with?
metronidazole
Which protozoa is commonly found in bodies of water, prisons, daycare, and mental health institutions?
Giardia lamblia which is spread fecal/oral from cysts in feces
How do you diagnose and identify giardia lamblia?
Diagnose from cysts or trophozoites in stool, giardia antigen test, or string test. The trophozite: is pear shaped, has two nuclei that look like eyes, ventral sucking disk, and 4 pairs of flagella. Cyst looks like a potato with 4 nuclei
What are symptoms and treatment of giardia lamblia?
The trophozoites coat the distal villi causing lack of malabsorption and IgA deficiency. Also causes foul smelling diarrhea and flatulence. Treat with metronidazole
Which parasite is a gastrointestinal protozoa that has an infectious oocyst?
Cryptosporidium has oocyst which is shed in stool of infected patients with Isocyclospora and Cryptosporidium. This parasite tends to infect immunocompromised.
What are symptoms and treatment for cryptosporidium parvum?
In immunocompetent: mild self limiting enterocolitis
In immunocompromised: 50 or more stools a day, dehydration that last a long time. You diagnose by seeing acid fast oocysts in stool and try treating with nitrazoxanide/paromycin
Parasite comes from imported fruits, causes diarrhea, and has acid fast oocysts in stool?
Cyclospora cayetanesis which you can treat with TMP-SMX
This parasite is fecal/oral from contaminated water, causes diarrhea in immunocompromised, and has acid fast oocysts in stool?
Cystoisospora beli which you treat with TMP-SMX
This parasite is sexually transmitted trophozoite, causes vaginosis?
Trichomonas vaginalis which you diagnose from cervical smear or antigen test and treat with metronidazole
This parasite causes retinochoridits and neurological deficits in immunocompromised patients?
Toxoplasma gondii
What are symptoms of toxoplasma gondii?
Asymptomatic in immunocompetent , in immunocompromised causes immunodeficiency, neuro deficits, pneumonitis, and retinochorditis.
Congenitally: trans-placental, usually unaffected but some show chorioretinis, jaundice, fever, anemia, hydrocephalus.
What is life cycle of toxoplasma gondii?
Cats are definitive host and eat oocysts in rodents and birds. Cats shed the oocysts in stool, and once they sporulate they become infectious. The oocysts can become motile tachyzoites or nonmotile bradyzoites.
What do you treat toxoplasma gondii (protozoa)?
Diagnose from PCR and serology and treat with Pyramethamine and Sulfas (in AIDs patientts)
This parasite is free living and is primary cause of amebic meningitis?
Naegleria fowleri (protozoa) which we find in warm fresh water and it’s susceptible to chlorine so we can treat with Amphotericin
This parasite causes keritinitis is free living and likes to infect contact lenses?
Acanthamoeba (protozoa)can be found in tap water because it’s chlorine resistant and cause keritinitis which causes blindness.