Geohelminths

Question 1

Geohelminths

Answer 1

Soil transmitted helminths

Question 2

Ascaris lumbricoides

Answer 2

large roundworm

• most common human helminthic infection
• largest nematode (roundworm)
• fertile eggs embryonate and become infective after 18days
• Eggs swallowed, larvae hatch , invade the intestinal mucosa, and are carried via the portal, then systemic circulation to the lungs.
• The larvae mature further in the lungs (10 to 14 days), penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed
• can survive 1-2 years

Question 3

Hookworm

• second most common helminth infection
• 2 species
• dry season dormancy?

Answer 3

• ->Necator americanus and Ancylostoma duodenale
• eggs hatch in 1-2 days
• after 5-10 days they become infective
• larva can survive 3-4weeks
• penetrate skin (foot?), heart, lungs, pharynx, intestine
• adults can survive many years
• vaccine developed using Ancylostoma caninum as test system
• hookworm outbreak 1800s - Swiss mines

Question 4

Phylum Nematoda Nematodes. ‘Roundworms’

General facts

Answer 4

• Major organs include:
• excretory gland and opening, ovary, cuticle, uterus, rectum, anus, fluid filled body cavity, intestine, pharynx, mouth

Eggs–>L1–>L2–>L3–>L4–>Adult
(four moults)
-25% humanity infected

Question 5

Trichuris trichiura

Answer 5

whipworm

Question 6

Trichinella spiralis

Answer 6

trichina worm
-encysted larva get into skeletal muscle
-humans ingesting undercooked pork
-larva released from nurse cells (stomach) into small intestine 
-adults deposit larva into lymph/blood/mucosa
-circulation and into muscle
-nurse cell larva complex formed
PATHOLOGY: heart failure, CNS damage

Question 7

Enterobius vermicularis

Answer 7

human pinworm

Question 8

Löffler’s Syndrome

Answer 8

• a Type I immune hypersensitivity
• IgR antibody levels associate with natural immunity
• allergy