Helminths : Round worms

Question 1

how are parasitic worms generally transmitted

Answer 1

3 main ways, via the ingestion of eggs and larvae, penetration of skin by larvae, inoculation of larvae by biting insects

Question 2

list the major parasitic worms

Answer 2

Nematodes (roundworms), Cestodes (tapeworm), Trematodes (tape worms/liver flukes)

Question 3

the most common parasitic infection and its mode of infection

Answer 3

Ascariasis infection is due to Ascaris lumbroides- inhabit and mate in the intestine, , eggs embryonate and are infective only in the soil

Question 4

Ascariasis life cycle - how does it occur?

Answer 4

Eggs pass in feces and embryonate in the soil for 10- 14 days. Following ingestion, they hatch an tear thru intestinal wall, move to the heart, lungs and finally to the breathing passages where they are swallowed.

Question 5

the most common complication of Ascaris

Answer 5

intestinal bowel obstruction

Question 6

Methods of diagnosis for Ascaris

Answer 6

Microscopic identification in the stool, identification in sputum and gastric aspirates during migration through the lungs before found in stool, have to determine if the eggs are fertilized or not

Question 7

Answer 7

fertilized egg of Ascaris lumbroides

Question 8

Answer 8

unfertilized Ascaris lumbroides - elongated and internal mass of irregular globules

Question 9

Answer 9

Trichuris trichuria ( human whip worm)

Question 10

how is the whip worm transmitted?

Answer 10

after ingestion, whipworms inhabit and mature in the colon. most common complication: gastrointestinal problems

Question 11

Answer 11

Trichuris Trichuria egg - characteristic “foot-ball shape”

Question 12

the two most common hookworms

Answer 12

Ancyclostoma duodenale - common in the Americas and Australia and Necator americanus - Middle East, North Africa, South Europe. Hookworm lifecycle - penetration of larvae into the skin by hookworm (ground itch)

Question 13

major complication of hookworm disease

Answer 13

iron-deficiency anemia

Question 14

best method for hookworm diagnosis

Answer 14

the most common method is microscopic examination of eggs in stools

Question 15

the two main hookworm species and their eggs

Answer 15

Necator Americanus and Ancylostoma - Both species have eggs which are morphologically identical. Examination of eggs cannot distinguish between species, oval or ellipsoidal shape with a thin shell