Intestinal Nematodes

Question 1

Ascariasis (Ascaris lumbricoides)

Answer 1

• ingestion of food contaminated with eggs
• most common helminthic infection in humans
• usually ASYMPTOMATIC
• penetrate small intestine and travel to lungs
• can cause obstruction of pancreatic or biliary ducts-pancreatitis, suppurative cholangitis, and liver abscesses.
• Ascaris pneumonia (rare): larvae fill alveolar airspaces

Question 2

Trichuriasis / Whipworm (Trichuris trichiura)

Answer 2

• ingested eggs in contaminated food, soil, drink
• Live in the Cecum or upper colon–children especially susceptible
• Invasion causes small erosions, focal active inflammation, loss of small amounts of blood
• Usually asymptomatic
• Heavy infestations causes cramping, abdominal pain, bloody diarrhea, weight loss and anemia

Question 3

Hookworms (Necator americanus, Ancylostoma duodenale)

Answer 3

• penetrate human epidermis on contact-enter venous circulation
• Duodenale = Asia / Mid East / Africa
• Americanus = Americas, Southeast Asia, Subsaharran africa.
• GI inflammation, iron deficiency anemia
• Most common cause of chronic anemia worldwide.

Question 4

Strongyloidiasis / Threadworm (Strongyloides stercoralis)

Answer 4

• penetrate human epidermis
• most cases asymptomatic, lethal disseminated disease in immunocompromised persons.
• reproduce in human hosts-autoinfection (rhabditiform larvae become infective filariform within host’s intestine and repenetrate perianal skin–new parasitic cycle
• Immunocompromised: autoinfection greatly increased-penetrate intestinal walls and disseminate leading to ulceration, edema, and severe inflammation leading to sepsis from gram(-) bacteria-FATAL

Question 5

Pinworm Infection (Enterobius vermicularis)

Answer 5

• infects appenix and large colon.
• goes to perianal skin-lys eggs
  eggs: cause itchy asshole syndrome.