(M) Nematoda: Morphology of Secernentea [Strongylida, Rhabtida, Oxyurida, Spirurida] (lecture-based)

Question 1

Order of the Subclass Secernentea

Answer 1

• Ascaridida
• Strongylida
• Rhabditida
• Oxyurida
• Spirurida

Question 2

Species under Ancylostomatoidea

Answer 2

• Necator americanus
• Ancylostoma duodenale
• Ancylostoma caninum
• Ancylostoma braziliense

Question 3

Order of the super family Ancylostomatoidea

Answer 3

Strongylida

Question 4

Species under Metastrongyloidea

Answer 4

Angiostrongylus cantonensis

Strongylida superfamily

Question 5

Species under Rhabdiascoidea

Answer 5

Strongyloides stercoralis

Question 6

Order and Super family of Strongyloides stercoralis

Answer 6

Rhabditida & Rhabdiascoidea

Question 7

Sp. under Oxyuroidea

Answer 7

Enterobius vermicularis

Question 8

Sp. under Gnathostomatoidea

Answer 8

Gnathostoma spinigerum

Question 9

Sp. under Filarioidea

Answer 9

• Wuchereria bancrofti
• Brugia malayi
• Loa loa
• Onchocerca volvulus
• Mansonella ozzardi
• Mansonella persians

Question 10

Strongylida

Feeding Stage
250 um
Open Mouth
Bulbous Esophagus
Long, Narrow Buccal Cavity

Answer 10

Rhabditiform larva

Question 11

Strongylida

700 um
Closed Mouth
Pointed Tail

Answer 11

Filariform larvae

infective stage for hookrowms

Question 12

idenfity larva

• 250 um; Short Buccal Cavity
• Prominent Primordial Genitalia
• Compared to hookworms, the primordial genitalia is more prominent in Strongyloides stercoralis.
• Club-Shaped Esophagus w/ Posterior

Answer 12

Rhabditiform larva

Question 13

Rhabditida

DF Rhabditiform larva

Answer 13

Club-shaped esophagus

Question 14

Oxyurida

Prominent Cephalic Alae.
Bulb-like Esophagus.
Female: Sharply-Pointed End
Male: Curved Caudal End
Egg: Described as D-Shaped or Lopsided Egg.

Answer 14

E. vermicularis

Question 15

Oxyurida

DF of Male E. vermicularis

Answer 15

bulb-like esophagus

Question 16

Spirurida

Has Sub-globose Cephalic swelling separated from the remainder of the body by Cervical Constriction.
Male: Pseudo-Bursa
Female: Slightly Post-equatorial in position

Answer 16

Gnathostoma spinigerum

Question 17

Spirurida

Ovoid, Transparent Shell
Superficially Pitted
* Mucoid Plug in one end

Answer 17

Gnathostoma spinigerum

Question 18

DF of Egg Gnathostoma spinigerum

Answer 18

Mucoid plug in one end

Question 19

Strongylida

Male: 7-9 mm x 0.3 mm diameter
Female: 9-11 mm x 0.4 mm diameter
Egg: 64-76 x 36-40 microns elongate with transparent shell, 2-8 cell stage of development.
Filariform Larva: With conspicuous striations of the sheath, tail-end forms a wide angle with the sheath

Answer 19

NEcator americanus

Question 20

Strongylida

Male: 8-11 mm x 0.4-0.5 mm diameter
Female: 10-13 mm x 0.6 mm diameter
Egg: Same as N. americanus but more rounded.
Filariform Larva: With less conspicuous striations of the sheath, narrow angle between tail and sheath.

Answer 20

A. duodenale

Question 21

Metastrongyloidea

Adult Female
* Barber-pole Appearance.
* The Anterior End of Worm is on the Top.
* The Scale Bar is 1mm

Answer 21

Angiostrongylus cantonensis

Question 22

Metastrongyloidea

• Tail of adult male of Angiostrongylus cantonensis, showing Copulatory Bursa and Long Spicules (arrows).
• Scale bar is 85 um.

Answer 22

Angiostrongylus cantonensis

Question 23

Sheathed Filiaria worms

Answer 23

• Wuchereria bancrofti
• Loa loa
• Brugia malayi

Question 24

Filarial worms

• The Adult Worms of W. bancrofti, inhabit the Lymphatic Vessels and Glands.
• Minute, Thread-Like, Smooth-Skinned, and Tapered on Both Ends.
• But Bluntly Rounded At The Most Terminal

Answer 24

Adult morphology W. bancrofti

Question 25

# Filarial worms Size: 40mm long x 0.1mm in diameter Sharply Curved Posterior.

Answer 25

Male W. bancrofti

Question 26

# Filarial worms Size: 80-100mm x 0.24-0.30mm With Vulva at Cervical Region, Single Uterus, but all the remaining reproductive organs are paired.

Answer 26

Female W. bancrofti

Question 27

# Filarial worms Size: 244-296um long x 7.5-10 um in diameter Sheathed with Graceful Curves. Bluntly Rounded Anterior w/ Short Space Devoid of Nuclei. Pointed Caudal Part. Smooth Cuticle. Body Nuclei Are Equidistant And Regularly

Answer 27

Microfilaria Wuchereria bancrofti

Question 28

# Filarial worms Male Size: 13-23 mm long x 70 - 80 um in breadth. Female Size: 43 - 55mm long, 130 - 170 um. Microfilaria Size: 177-230 um Bluntly Rounded Anterior. Sheathed, with a Stiff & Kinky Body. Unevenly Distributed Body Nuclei. Two Prominent Terminal Nuclei

Answer 28

Brugia malayi

Question 29

# Filarial worms DF of Microfilaria size

Answer 29

2 prominent terminal nuclei

Question 30

# Filarial worms Male Size: 30 - 34 mm x 0.35 - 0.43 mm Female Size: 40 - 70 mm x 0.5 mm Microfilaria Size: 250 - 300x6 - 8um Rounded Anterior End Very Small or No Cephalic Spaces Irregular Curves of Body covered with Thin Transparent Sheath. Irregularly Distributed Body Nuclei that reached up to the Caudal End.

Answer 30

Loa loa

Question 31

# Filarial worms Unsheathed filaria worms

Answer 31

* Onchocerca volvulus * Mansonella ozzardi * Mansonella perstans

Question 32

# Filarial worms Found in in Lymphatic Fluids and Both Adults. * May be found in the Skin and Subcutaneous Tissues where they produce Fibrous Nodules.

Answer 32

Microfilariae O. volvulus

Question 33

# Filarial worms this are are White, Opalescent, and Transparent. * With Distinct Transverse Striations Of The

Answer 33

Adult worms O. volvulus

Question 34

# Filarial worms Male Size: 19-24 mm long x 130-210 um. Female Size: 3.5-50 mm x 270-400 um. * Microfilariae Size: 315-360 um x 6 um. * With Both Ends Free of Nuclei. They may be found in the blood, urine, and sputum. * But more commonly in the Lymphatic of the Connective Tissues. * Cutaneous layers in an Area around the Adult Worms in the Corneal Conjunctivae.

Answer 34

O. volvulus

Question 35

# Filarial worms Male Size: 45 mm long × 60 um Female Size: 70 - 80 mm long × 120 um Microfilaria Size: 200 um x 4.5 * The body nuclei fill up the entire body. * No Distinct Space at Cephalic or Tail

Answer 35

Mansonella perstans

Question 36

# NECATOR AMERICANUS (New World Hookworm) DF of Rhabditiform larva

Answer 36

Inconspicuous genital primordium at midpoint

Question 37

# NECATOR AMERICANUS (New World Hookworm) DF of the copulatory bursa

Answer 37

Bi-partite dorsal ray (characteristic feature)

Question 38

# NECATOR AMERICANUS (New World Hookworm) DF Necator americanus buccal sample

Answer 38

buccal capsule with a pair of thin semi-lunar cutting plates

Question 39

# ANCYLOSTOMA DUODENALE (Old World Hookworm) DF Rhabditiform larva

Answer 39

Inconspicuous genital primordium at midpoint

Question 40

# ANCYLOSTOMA DUODENALE (Old World Hookworm) DF filariform larva

Answer 40

W/ less conspicuous striations of the sheath, narrow angle between tail and sheath

Question 41

# ANCYLOSTOMA DUODENALE (Old World Hookworm) Characteristic feature of the copulatory bursa

Answer 41

Tri-partite dorsal ray

Question 42

# Angiostrongylus cantonensis (Rodent Lung Worm) Diagnostic feature of Adult female

Answer 42

“barber’s pole appearance”

Question 43

# STRONGYLOIDES STERCORALIS (THREADWORM) DF of the Esophagus (rhabditiform larvae)

Answer 43

* Club-shaped Esophagus w/ Posterior Bulb * Conspicuous/prominent genital primordium

Question 44

# STRONGYLOIDES STERCORALIS (THREADWORM) DF of filariform larva

Answer 44

→ Notched & bifid caudal end

Question 45

# ENTEROBIUS VERMICULARIS (PINWORM, SEAT WORM, OR SOCIETY WORM) DF of Male

Answer 45

bulb-like esophagus without true buccal capsule

Question 46

# ENTEROBIUS VERMICULARIS (PINWORM, SEAT WORM, OR SOCIETY WORM) Egg shape

Answer 46

D-shaped or Lopsided egg appearance

Question 47

# Gnathostoma spinigerum DF of adult

Answer 47

Cephalic end: sub-globose, the swollen part w/ constriction

Question 48

# Gnathostoma spinigerum DF of egg

Answer 48

Prominent mucus plug at 1 pole (diagnostic)

Question 49

Spiral dark-colored body producing "barber's pole" appearance

Answer 49

Angiostrongylus cantonensis

Question 50

# ENTEROBIUS VERMICULARIS DF Gross/Adult

Answer 50

Cephalic alae and prominent bulbous esophagus