Ascaris lumbricoides Flashcards

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.