Ascaris lumbricoides Flashcards

Study Notes

Ascaris Lumbricoides

Classification: Nematode/roundworm, genus Ascaris.
Size: Adult worms can grow up to 35 cm in length.
Disease: Ascariasis is the condition caused by infection.

Pathogenesis and Symptoms

Infection process:
- Eggs are ingested, maturing into larvae in the intestine.
- Larvae penetrate the duodenal wall, migrating to the lungs.
- In the lungs, larvae develop and reach alveoli, are coughed up, and swallowed back into the intestine to mature into adults.
Symptoms may include:
- Asymptomatic cases are common.
- Abdominal cramping.
- Dry cough and fever during larval migration in the lungs.
- Malnutrition.
- Risk of intestinal or biliary obstruction.

Epidemiology

Transmission occurs through the fecal-oral route via egg ingestion.
Ascaris lumbricoides is the most prevalent helminth globally.

Treatment Options

Medications: Albendazole or mebendazole paralyze worms, allowing them to be expelled with feces.
Surgical intervention may be necessary for ectopic migrations.
Supportive care is provided during episodes of pneumonitis.

Laboratory Diagnostics

Fecal examination can identify eggs.
Sputum tests may reveal larvae.
Eosinophilia, an increase in eosinophils, can be observed.

Genus Toxocara

Species include:
- Toxocara canis (from dogs).
- Toxocara cati (from cats).

Taxonomic Structure

Classification: Also a nematode/roundworm, specifically a tissue parasite.
Human infection does not result in the maturation of larvae into adult worms.

Pathogenicity and Symptoms

Condition: Toxocariasis, also known as visceral larvae migrans.
Symptoms include:
- Fever.
- Diarrhea.
- Wheezing.
- Eosinophilia.
- Hepatitis.
- Possible blindness due to larval migration.
Larvae migrate erratically through the body, causing inflammation until they die.

Epidemiology

Reservoir: Domestic animals, particularly cats and dogs.
Transmission is through the ingestion of eggs found in feces.

Treatment Options

Same medications as for Ascaris lumbricoides: Albendazole or mebendazole.

Laboratory Diagnostics

Diagnostic methods include serology and clinical findings indicating infection.
Eosinophilia is also noted in Toxocara infections.

Description

Test your knowledge of Ascaris lumbricoides' taxonomy, morphology, and pathogenesis with these flashcards. Explore the structure, symptoms, and prognosis of this notable nematode. Perfect for students of parasitology and medical biology.