Phasmidea Flashcards
smallest nematodes measuring 2.2 x 0.04 mm
Strongyloides
colorless, semi-transparent, with a finely striated cuticle
Parasitic or Filariform Female
Strongyloides
• it has a slender tapering anterior end and a short conical pointed tail
“ the short buccal cavity has 4 indistinct lips
the long slender esophagus extends to the anterior fourth of the body, and the intestine is continuous to the subterminal anus
the vulva is located 1/3 the length of the body from the posterior end
• the uteri contain a single file of eicht to twelve thin-shelled, transparent, segmented ova
Strongyloides stercoralis (Threadworm)
Parasitic or Filariform Female
measures 1 mm by 0.06 mm and is smaller than the parasitic fernale
” it has a muscular double-bulbed esophagus and the intestine is a straight cylindrical tube
Free living
Strongyloides
” measures 0.7 mm by 0.04 mm and is smaller than the female
• it has a ventrally curved tail, two copulatory spicules, a gubernaculum but no caudal alae
Free-living Male
Strongyloides
rarely seen in the stool specimen
” it has a clear, thin shell and are similar to those of hookworms except that they measure about 50-58 micra by 30 to 34 micra
Eggs
Strongyloides
•they have cuticular alar expansions at the anterior end and a prominent posterior esophageal bulb
Adult Worm Enterobius vermicularis (Pinworm)
Male Worm
spindle-shaped
• measures 2 to 5 mm by 0.1 to 0.2 mm in greatest diameter
” oral end is provided with 3 lips and a pair of laterally placed cephalic “alae” or wings
- bursa is greatly reduced and designated as “caudal alae” which is supported by 6 pairs of caudal papillae
” it has a characteristic curved tail with a single spicule
• posterior end is strongly curved ventrad
• relatively smaller than the female worm they are rarely seen because they die after copulation
Enterobius vermicularis
Female Worm
measures 8 to 13 mm in length by 0.3 -0.5 mm in greatest diameter
• it has a long pointed tail hence the common name pinworm
• vulva opens in front of the middle third of the body
” vagina is long, extending posteriorly some distance from the vulva before
it joins the paired genital organs
the uteri of the gravid female are distended with eggs
they are capable of laying as much as 4, 672 to 16, 888 eggs/day
Enterobius vermicularis
• are asymmetrical, with one side flattened and the other side convex
• measures 50 to 60 micra by 20 to 30 micra averaging 55 by 36 micra
“ fully convexed
• the translucent shell consists of an outer, triple albuminous covering for mechanical protection and an inner lipoidal membrane for chemical protection
” outside the host, eggs become infective in four to six hours
Ova
Enterobius vermicularis
Ascaris lumbricoides (common name)
Giant Intestinal Roundworm
” also known as the pink worm
• they have the so-called “polymyarian type” of somatic muscle arrangement in which cells are numerous and project well into the body cavity
• they have anterior 3 lips
relatively large worms
Adult Worm
Ascaris lumbricoides
measures 10 to 31 cm by 2-4mm in diameter with smooth striated cuticles
they have a terminal mouth with three lips and a sensory papillae
they have a ventrally curved posterior end with two spicules
a single, long, tortuous tubule is found in the posterior 2/3 of the body
posterior end is curved ventrad
Male Worm
Ascaris lumbricoides
.
measures 22 to 35 cm with smooth striated cuticles
they have a terminal mouth with three lips and a sensory papillae
they have paired reproductive organs in the posterior 2/3
posterior end is conical and straight
productive capacity of 26 million eggs or 200, 000 eggs per day
Female Worm ascaris lumbricoides
• measures 88 to 94 micra by 39 to 44 micra, longer and narrower than fertilized eggs
• it is thin-shelled with an irregular mammillated coating filled with refractile granules
” vitelline membrane is absent
” has thinner shell composed of inner chorionic and outer irregular coating
of albumin
” they are difficult to identify and are found only in the absence of males
Unfertilized Egg
Ascaris lumbricoides