GI Parasite 2/2 Flashcards
What are Helminths?
-worms,
common features shared: no true respiratory system (surface tegument), eggs are usually not laid in human hosts
-sexual reproduction
-eukaryotic
Name 3 Roundworms…what family are they a part of?
Helminths
Roundworms: Pinworms, Ascaris, Strongyloides
Name 2 Tapeworms….what family are they a part of?
Helminths
Tapeworms: Echinococcus, Taenia
Name 1 Fluke…what family are they a part of?
Helminths
Flukes: Schistosoma
What are the 3 categories of Helminths?
Roundworms, Tapeworms, Flukes
What are Nematodes? Can they survive outside the human host?
- Garden Worms, part of the Round Worms
- Free-living: survive outside the human host
Pinworms: infect who? How? Patent Period? Symptoms? Diagnosis?
- aka Enterobius Vermicularis
- Children’s infection
- Nocturnal infection = female comes out of the anal canals and lays her eggs in the perianal area → itch → child scratches → eggs under the finger nails and passed on to others OR the child unknowingly eats them/autoinfection (children aren’t that hygienic)
- 4 – 6 weeks: the period between infection and detection
- Symptoms: Aymptomatic, Vaginal, Anal Itch
- Diagnosis: Eggs, Sticky Tape
Ascaris Lumbricoides: Infect what part of the human body? How? Specific Climate? Symptoms? Diagnosis?
a. Large intestinal worm
b. Embryonisation occurs in soil, 2 – 4 weeks; need to develop outside the human host before the can be transmitted
c. Pathology is due to the large size of the worm – can cause blockage of various areas
d. Needs to develop in warm climates
e. Infective eggs swallowed → larvae hatch → invade intestinal mucosa → portal system → systemic circulation → larvae mature further in the lung → penetrate alveoli → ascend the bronchial tree → drop down trachea → get to the SI → adult worms → eat nutrients; Symptoms follow the route of maturation
f. Symptoms: Assosciated with larvae migration - pneumonitis, intestinal obstruction, chronic cough, asthma etc
Diagnosis: Eggs in feces
Schistosoma Mansonii: Parasitic? What organ do they infect? Transmission? Symptoms? Diagnosis?
a. All parasitic
b. Blind gut, organs in parenchyma
c. Lives in intestinal veins
d. Larvae can penetrate skin
e. Transmission by FRESH WATER SNAILS – acquired by fresh water contact
f. Eggs are eliminated via urine or feces → larvae infect snails → mature in snails and leave the snails → infect humans via penetrating the skin → migrate to portal blood in the liver → adults → migrate to the veins of the intestine/bowels (mesenteric) → feces
g. Symptoms: Swimmers Itch, light infections = itch, Heavy Infection = hepatomegaly, splenomegaly, pulmonary fibrosis
h: Diagnosis: Eggs in feces, urine
Strongyloides Stercoralis? How many hosts need to complete life cycle? Target Organ? Symptoms? Diagnosis?
a. Infection by skin penetration
b. Embryonisation in the colon
c. Autoinfection is possible
d. GN hyperinfection (the protozoa is covered in GN bacteria) can occur in immunosuppression
e. Larvae penetrate the skin → migrate to the SI (via entering the circulatory system → lungs → climb up bronchial tree → swallowed) → become adults → female lay eggs in the intestinal mucosa → eggs hatch and migrate into the lumen → excreted in the stool OR autoinfection within the LI → penetrate the LI and migrate to other areas
Symptoms: Assosciated with larvae migration - pneumonitis, intestinal obstruction, chronic cough, asthma, GN HYPERINFECTION
Diagnosis: Eggs in Feces
Echinococcus Granulosus: What kind of infection? Lifestyle? Are humans the intended hosts? Cysts?
a. Zoonotic infection
b. Prey-Predator lifestyle
c. Humans are accidental intermediate hosts; are not needed for transmission
d. Hyatid Cysts: proliferation occurs within the cysts producing → protoscolesces
e. Resides in the definitive host: canines → release eggs in the feces → eaten by various farm animals (i.e. sheep) → egg hatches in the SI → penetrates the intestinal wall → liver and lungs (and other organs)→ hyatid cysts → produces protoscolesces → eaten by another intermediate host → evaginate and attach to the intestinal mucosa → adult
Symptoms: Hyadatic cysts (liver and lungs), vary with the number of cysts, hypersensitivity reaction - shock
Diagnosis: Imaging techniques, serology
Taenia Soilum: Cysts? Lifestyle? Human Hosts? Symptoms? Diagnosis?
a. Cestode parasites → cysts caused by the young form of the pork tapeworm
b. Zoonotic, Prey-Predator life cycle
c. Humans can be both definitive and intermediate hosts
d. Neurological disease is a major symptom
e. Eggs are passed with feces → cows/pigs become infected as they ingest the eggs → hatch in the intestine → invade through the intestinal wall → migrate to the striated muscle → develop into cysts → meat eaten by humans → turn into adults in the intestine
Symptoms: Cysts in subcutaneous and neural tissues
Diagnosis: Imaging techniques, serology
