Parasites 2 Flashcards
Protozoan Parasite Basics
Transmission: Fecal-oral (food or drink), Anal-oral sex, ingest thick-walled environmentally hardy cysts which release active trophozoites in the intestine… waterborne outbreaks!
Guardia Lamblia
- “Beaver Fever”
- OLD MAN GLASSES…
- Watery diarrhea from malabsorption
- May last for weeks to months
- disc like things that block villi
Diagnosis: Stool microscopy and duodenal aspirate
Cryptosporidium sp.
- Watery diarrhea, “Gum to bum”
- Two types:
- Immunocompetent: Milder, self limiting (days)
- Immunocompromised: Severe, up to 20L/day, fluid loss for months to years!
- Resistant to treatment!
- Waterborne outbreaks
Diagnosis: Stool microscopy
Amoebiasis
- Diarrhea (with mucus, blood, and pus)
- Extraintestinal amebiasis… abscesses in distant organs
- Asymptomatic cyst passage
- Infection: Fecal/Oral by ingestion! of hard cysts… releasing trophozoites in the intestine…
- Invasion of intestinal wall and dissemination to distant organs.. eats right under epithelial cells and creats a little ulcer!
- Very resourceful and dangerous!
- Look in walls… not in middle of abscess.
Source: Asymptomatic carriers, flies, cockroaches
Distribution: WorldwideDiagnosis: Stool microscopy (E. Dispar is nice! E. Histolytica is DANGEROUS gives you the symptoms), Have to do PCR TO KNOW WHICH ONE YOU HAVE!
Ascaris Lumbricoides
You swallow eggs, eggs hatch in intestine, cross intestinal wall, into bloodstream and through liver and then back into heart! Once they pass large ciruclation go to small… and go to lung! But somewhere around end respiratory system those larva wake up from passively floating and start moving… they then break through the alveoli wall… then actively start crawling up all the way to the back of the throat! This is just what ascaris needs and go into stomache and into intestine… and by now they are adults and then reproduce in intestine… Ascaris wants to stay in same place as adults so they move around so they dont get pooped out!
Clinical Manifestations:
- Larval migration: pulmonary symptoms.. ex. asthmatic attack.
- Adult worm:
- Asymptomatic
- nutritional effect
- Complications: obstruction, worm migration
- If it sees small opening.. it will squeeze in there! Two things cause worm migration… spicy diet… high fever… Start antiworm therapy… They can try and worm into bile duct… leading to Gang Green!!!
Epidemoiology: Fecal oral transmission… HUGE DAILY GLOBAL CONTAMINATION… 9 X 10^14.. 1 in 4 people infected..
Cestodes… Taenia Saginata vs Taenia Soilium
TAPEWORMS
Taenia Saginata: Beef! Only get if ingest LARVA of undercooked beef. Eggs aren’t infectious!
Taenia Soilium: Pork! Infects various parts of body! Eggs AND larva are infectious to us! Egg can develop into larva but can’t change into adult, since wrong place/wrong time, so then it will migrate through tissues! It is more dangerous since it can infect brain, muscle, and the eye (cysticercus)
***Morphology of Taenia Species
Adult: Head = scolex with hooks or suckers. and body with chain of segments called the proglottids
Immature Form: Egg, Larva called cysticercus*
Entamoeba Histolytica
Acquire from flies and cockroaches landing on food! Have to do PCR to know if it is Dispar or Histolytica!
Hydatid Disease
- Infection with larval form of Echinococcus granulosus
- Two hosts:
- Definitive: Adult form… dog and wild canids
- Intermediate: Larval form… herbivores, humans
Disease: Continuously growing cysts in liver, lung and brain over months to years causing local pressure effects! Cysts can also rupture and release toxins which are very dangerous!
These can migrate/disseminate into diff. tissues! These CANNOT mature in humans!
Trichomoniasis
- Called Strawberry Cervix
- Caused from Trichomonas Vaginalis
- From sexual intercourse. Egg needs non-harsh environment
Enterobiasis
- Pin worm!
- Can do tape test… lays eggs on outside of anus.
