Nematoda

Question 1

Ascaris lumbricoides

Answer 1

Male has a curled tail with protruding spicules
Female has straight pointed posterior end
Most pathogenic roundworm of humans (also pigs) - intestine
Causes: ascariasis

Question 2

Ascaris lumbricoides eggs

Answer 2

Round to oval in shape, dark brown in colour
Shell wall is thick and bumpy, embryos are single celled
Fertilized ova are oval with bumpy shape, unfertilized are longer and narrower
Shell layers provide resistance - ideal for intestine

Question 3

Trichuris trichiura

Answer 3

Long and whip shaped, anterior end is smaller
Males have coiled caudal end with single spicule
Adults have huge esophagus called stichosome
Repro organs in thick posterior end
Not prolific (not many ova)
Occurs in colon and cecum of humans
Causes: trichiuriasis (dysentery, anemia, growth retardation)

Question 4

Trichuris trichiura eggs

Answer 4

Bilaterally symmetric, yellow-brown
Barrel shaped, polar plugs at either end
Thin and smooth outer shell
Embryos are single celled
Persist in environment for years

Question 5

Trichinella spiralis

Answer 5

Males and females have esophagus
Male has bursal lobes at posterior end
Females larger than males (they are ovoviviparous)
Causes: trichinosis/trichiniasis/trichinelliasis
Larvae found in muscle fibers of pigs and humans

Question 6

Ancyclostoma caninum

Answer 6

Both male and femal show dorsal curvature at anterior end
Buccal capsule shows ventral teeth
Dorsal ray of the copulatory bursa in males has 3 branches at end of fork
Spicules of male are not fused
Inhabit small intestine of dog hosts

Question 7

Necator americanus

Answer 7

Females larger than males
Buccal cavity used to attach worms to mucosa of small intestine (has teeth)
Male has copulatory bursa with spicules
Females have conical tail, vulva in middle of body, 2 ovaries
Causes hookworm disease in vertebrate host

Question 8

Enterobius vermicularis

Answer 8

Females larger
Both sexes have cephalic alae (lips) surrounding the mouth and esophageal bulb
Females have pointed tail
Male has single spicule and posterior curves in ventrally
Causes: enterobiasis in vertebrate host
Inhabits small intestine

Question 9

Enterobius vermicularis eggs

Answer 9

Oval or football shaped and colourless
1 side is somewhat flattened
Shell is thin and smooth
Enbryo is single celled