Roundworms: Strongyloidiasis

Question 1

In what regions might you find cases of Strongyloidiasis?

Answer 1

Primarily in tropical/subtropical areas

Question 2

How dangerous is Strongyloidiasis?

Answer 2

Potentially lethal

Question 3

How does Strongyloidiasis impact US populations?

Answer 3

Not overly common in US, just sporadic cases.

Question 4

Explain the life cycle of Strongyloidiasis

Answer 4

• Adult worm lays eggs
  rhabitiform larvae (non infectious) penetrate GI system, soil or anus - leads to AUTOINFECTION
• Filariform larvae (mature - penetrates another host
  
  • penetrates skin, blood, lung, GI

Question 5

What is the Rhabitiform larvae?

Answer 5

Less mature larvae, normally passed in stool, not immediately infectious

Question 6

What is Filariform larvae?

Answer 6

Rhabitiform larvae mature in soil to filariform larvae, which are infections, can penetrate skin and cause human infection. Normally these are passed in stool.

Question 7

Explain the immunocompromised auto infection process

Answer 7

In the host’s GI, non-infectious rhabitiform larvae generate filariform larvae (normally happens in soil).

• Passed in stool, re-infect in peri-anal area
• OR they pass to anus area and reinfect
• MASSIVE infection! - years later!

Question 8

What are the clinical manifestations of a low infection of Strongyloidiasis?

Answer 8

Asymptomatic

Question 9

What are the clinical manifestions of a high infection of Strongyloidiasis?

Answer 9

GI symptoms:

• abd pain, nausea, ulcer-like sxs or diarrhea +/- malabsorption
• Respiratory sxs: pulmonary migration may cause LOEFFLER’S syndrome
• Disseminated strongyloidiasis or hyper infection
  
  • auto infection may be fatal
  • need to check history before any immunosuppressive therapy.
  • worms can live in host for up to 40 years!

Question 10

How do you diagnose Strongyloidiasis?

Answer 10

Stool exam for rhabditiform larvae, eggs rarely

• serial exams may be necessary
• Eosinophilia may be a hint
• index of suspicion
• Duodenal aspirates can be sampled (not usually done)
• Ab blood test of stool negative but still suspect
  - EIA may be best

Question 11

How do you treat Strongyloidiasis?

Answer 11

Goal is to eradicate and avoid future issues

- IVERMECTIN for 2 days or thiabendazole

Question 12

How do you prevent Strongyloidiasis?

Answer 12

• In endemic areas, wear shoes
• better sanitation
• R/o before ummunosuppressants

Question 13

If a patient is immunocompromised, before starting treatment what should the physician do?

Answer 13

Screening test for worms!

• antibody blood test
• EIA

*if start treatment without testing it will increase worm load and cause severe enterocolitis (GI breakdown).