(M) Nematoda: Secernentea: Rhabditida (lecture-based)

Question 1

Superfamily of Rhabditida

Answer 1

Rhabdiascoidea

Genus Stronglyloides stercoralis

Question 2

• Primarily in warm climates
• Transmission occurs mainly in tropical and subtropical regions but also in countries with temperate climates.
• An estimated 30-100 million people are infected worldwide. Precise data on prevalence are unknown in endemic countries.
• Infection is acquired through direct contact with contaminated soil during agricultural, domestic and recreational activites

Answer 2

Strongyloides stercoralis

Question 3

Strongyloides stercoralis

AKA

Answer 3

thread worm

Question 4

Strongyloides stercoralis

Morphology available

Answer 4

• Free-living (rhabditoid) adults
• Parasitic female
• Rhabditiform larva
• Filariform larva

Question 5

More complex than most of the nematodes because there is alternation between Free-living Cycle and Parasitic cycle

Answer 5

Strongyloides stercoralis

Question 6

Strongyloides stercoralis

External autoinfection:

Answer 6

Perianal area

Question 7

Strongyloides stercoralis

Internal autoinfection

Answer 7

intestinal mucosa

Question 8

Strongyloides stercoralis

Infective stage

Answer 8

Filariform larvae

Question 9

Strongyloides stercoralis

What stage is yield later in the stool

Answer 9

Rhabditiform larva

Question 10

Strongyloides stercoralis

When Rhabditiform larva passes out in the stool, it can now fo to what cycle?

Answer 10

Free living cycle

Question 11

Strongyloides stercoralis

The adult female lays its egg, and this egg will develop and morph into

Answer 11

Rhabditiform larva

The Rhabditiform larvae develop into infective filariform

Question 12

Strongyloides stercoralis

happens because the rhabditiform larva has gone out to the perianal area. But it is still in the perianal area within the body of the host, but it penetrates the perianal skin and migrates randomly to other organs. When that happens it will develop later on to a Filariform larva and the cycle will continue.

Answer 12

External autoinfection

Question 13

Strongyloides stercoralis

happens when it is still in the intestine. The Rhabditiform larva will develop within the intestine as Filariform larva and penetrates again the intestinal mucosa or other parts of the body and again continues its lifecycle.

Answer 13

Internal Autoinfection

Question 14

Strongyloides stercoralis

TOF. Internal & External Autoinfection which corresponds to the parasitic cycle. Since it is still a parasite outside the human host.

Answer 14

F (inside/within)

outside lang kapag free living

Question 15

Strongyloides stercoralis

Clinical manifestations

Answer 15

Strongyloidiasis, dermatologic, grastrointestinal, pulmonary, neurologic, life threatening among immunodeficient patients

Question 16

Strongyloides stercoralis

• Chronic Parasitic Infection of Humans.
• Caused by Strongyloides stercoralis.

Answer 16

Strongyloidiasis

Question 17

Strongyloides stercoralis

The larva migrates into the skin, causing cutaneous larva migrans.

Answer 17

Dermatologic: Larva Currens

Question 18

Strongyloides stercoralis

Laboratory diagnosis

Answer 18

• Demonstration of the Rhabditiform Larva (or Filariform) in the Stool.
• Rhabditiform larvae may also be recovered in the Duodenal Fluid and Sputum.
• String Test
• Harada-Mori or Baerman technique to Culture the larval Stages.

Question 19

Strongyloides stercoralis

Treatment

Answer 19

• Mebendazole
• Albendazole
• Thiabendazole

Question 20

Members of Cutaneous Larva migrans

Answer 20

• A. caninum
• A. braziliense
• A. ceylanicum
• Strongyloides stercoralis