Nematoda Part 1

Pseudocoelomic activity

A nematodes cylindrical form can be attributed to what?

False

T/F: Round worms are generally cylindrical, tapered at both ends, and are segmented

Free-living

Are nematodes generally free-living or parasitic?

Ascaris lumbricoides

This is the largest and the most common intestinal roundworm

Man

This is the only host of A. lumbricoides

Jejenum and Ileum

In what areas of the intestine does A. lumbricoides usually reside in?

Ova

Diagnostic Stage for A. lumbricoides

Fertilized Egg

Under the microscope of a patient suspected of being invaded by A. lumbricoides, you spot a rounded object with an external mamillated layer. What stage of A. lumbricoides are you most likely seeing?

Inner vitelline membrane, Thick transparent middle layer, and outer mamillated albuminoid layer

What are the 3 layers of the fertilized of A. lumbricoides

Decorticated Fertilized Egg

Term used to describe a fertilized A. lumbricoides egg without the mamillated coat

Embryonated Egg

This is the infective stage of A. lumbricoides

The inner 2 layers

The unfertilized egg of A. lumbricoides is missing which layers?

Soil

Where does the embryonated egg of A. lumbricoides need to be developed?

Fecal-oral route

How can A. lumbricoides infect a host?

False

T/F: Unfertilized A. lumbricoides eggs also infect when ingested

Lungs

This is the most common area of migration for A. lumbricoides larva

Loeffler’s Syndrome

This is the allergic eosinophilic infiltration of the lung when adult A. lumbricoides reaches it

Upward

Fever may causes A. lumbricoides to travel in what direction?

Formalin Ether Concentration Technique, Direct Fecalysis, Kato-Katz

3 diagnostic methods for A. lumbricoides

Albendazole, Mebendazole, Ivermectin

3 drugs usually used for A. lumbricoides infection

Hookworms

This species of nematodes suck blood voraciously and damage the mucosa

Small Intestines

What part of the body do hookworms usually reside in?

Ancylostoma duodenale

This is also known as the old world hookworm

Necator americanus

This is also known as the new world hookworm

1 > 2

QC: Size of (1) A. duodenale (2) N. americanus

1 > 2

QC: Pathogenicity of (1) A. duodenale (2) N. americanus

A. duodenale

Which hookworm has their head bent in the same direction?

N. americanus

Which hookworm has their head bent in the opposite direction?

A. duodenale

Which hookworm has 4 vertical teeth and 2 dorsal knob-like teeth

N. americanus

Which hookworm has 2 ventral and dorsal chitinous cutting plates

A. duodenale

Which hookworm has a caudal spine in their female species?

1 > 2

QC: Pulmonary reaction for (1) A. duodenale (2) N. americanus

Ovoidal, thin-shelled, colorless with a empty space between the shell and content

Describe the morphology of a hookworm egg

Filariform Larva (L3)

Infective stage of hookworms

Ground itch/Coolie Itch

This symptom of hookworms is attributed to the cutaneous penetration of larva usually occuring at the feet

Anemia and Hypoalbuminemia

The ability of hookworms to suck blood is attributed to this clinical finding

FECT, Direct Fecal Smear, Harada-Mori Technique

Diagnostic Methods of Hookworms

Albendazole, Mebendazole, Symptomatic Treatment

Treatment for Hookworms

Egg

Diagnostic Stage for hookworms

Trichuris thrichiura

The common name for this nematode is the whipworm

Large Intestine

In what part of the body does. T. trichiura attach to?

Football shaped with bipolar plugs

This is the characteristic appearance of T. trichiura eggs

Unembryonated Eggs

Which stage of T. trichiura is passed in the stool?

Anal and rectal prolapse

This is a characteristic clinical finding of heavy T. trichiura infections due to loss of muscle tone in that area

Hypochromic Anemia

What type of anemia is caused by T. trichiura infection?

Too many to count

Amount of eggs/smear in massive T. trichiura infections

<10 eggs/smear

Amount of eggs/smear in light T. trichiura infections

>50 eggs/smear

Amount of eggs/smear in heavy T. trichiura infections

Cellophane thick smear method

Smear method used for T. trichiura

Mebendazole and Albendazole

Treatment for T. trichiura infection

Enterobius vermicularis

The common name for this species of nematode is pinworm/seatworm

Spindle-shaped with a sharp tail

Morphology of adult E. vermicularis

Eggs

Diagnostic stage of E. vermicularis

Letter D appearance

Characteristic appearance of E. vermicularis eggs

Embryonated ova

Infective stage of E. vermicularis

Hand-to-mouth, airborne eggs in dust, reinfection through anus

Transmission of E. vermicularis

Nocturnal Itch

This is a hallmark clinical finding of E. vermicularis that reinforces the hand-to-mouth transmission route for children

Scotch tape swab

Smear technique used for E. vermicularis

Albendazole, Mebendazole, Pyrantel Pamoate

Treatment for E. vermicularis infection

Strongyloides stercoralis

The common name for this nematode is threadworm

Perpetuation via producing infective larvae from pathogenic females

Special type of transmission of S. stercoralis

Notch tail

Characteristic appearance of filariform larvae of S. stercoralis

1 < 2

QC: Length of buccal canal of (1) S. stercoralis (2) Hookworm

Rhabditiform larva

Diagnostic stage of S. stercoralis

Infected filariform larva

If the rhabditiform larva of S. stercoralis molts twice, what does it become?

Free-living adult male or female

If the rhabditiform larva of S. stercoralis molts four times, what does it become?

Filariform larva

Infective stage of S. stercoralis

Pneumonitis

This clinical symptom of S. stercoralis is attributed to inavsion of the lung

Disseminated form

This clinical form of S. stercoralis is common in people taking immunosuppressive drugs

Strongyloides examine after 5 days while hookworms are examined after 10 days

Difference between the harada-mori culture between strongyloides and hookworms

Embryonated egg

Infective stage of T. trichiura

Unembryonated egg

Diagnostic stage of T. trichiura