HOOKWORM Flashcards
(32 cards)
Name the two main hookworm species that infect humans.
Necator americanus and Ancylostoma duodenale
Which human hookworm tends to occur in cooler & drier regions?
Necator americanus
Which human hookworm is found in tropical & subtropical regions?
Ancylostoma duodenale
What is the common name for Ancylostoma duodenale?
Old world Hookworm
What is the primary habitat of hookworms in humans?
Small intestine
What is the mode of transmission for human hookworms?
Skin penetration
What is the infective stage of hookworms?
Filariform larvae
What is the diagnostic stage of hookworms?
Eggs in feces
What is the migration route of hookworms in the human body?
Heart-lungs migration
Name some reservoir hosts for Ancylostoma duodenale.
Dogs, cats, Hogs, lions, tigers, gorillas
What are some common laboratory diagnostic methods for hookworm infection?
Demonstration of eggs and adult worms in feces & aspiration of duodenal contents (DFS, Kato-Katz, FECT, Culture); Blood examination (anemia and eosinophilia) & stool exam showing (t) occult blood & Charcot-Leyden crystals.
Describe the general appearance of adult hookworms.
Small, pinkish & fusiform in shape. Anterior end is curved dorsally
Describe the oral cavity of Ancylostoma duodenale adult worms.
Provided with 4 hook-like teeth on ventral & 2 knob-like teeth on dorsal.
What is the typical size of a male Ancylostoma duodenale?
5-11 mm x 0.4-0.5 mm
What is characteristic about the posterior end of a male Ancylostoma duodenale?
Posterior end expanded in an umbrella-like fashion (copulatory bursa).
What is the typical size of a female Ancylostoma duodenale?
9-13 mm x 0.6 mm
Describe the posterior end of a female Ancylostoma duodenale.
Posterior end is tapering.
Describe the general morphology of a hookworm egg.
Ovoidal, thin-shelled, colorless. Possess segmented ovum with 4 blastomeres.
Do hookworm eggs float in saturated salt solution?
Yes, they float.
Long buccal canal, small genital primordium. Usually not found in the stool but may be found if there is a delay. 250-300 um long; 15-20 um wide.
hookworm rhabditiform larvae.
500-600 um long. Pointed tail. Sheathed.
hookworm filariform larvae.
Skin infection caused by filariform larvae entering the skin.
“Ancylostoma dermatitis” or “ground itch/dew itch”
Skin infection caused by hookworm larvae.
“creeping eruption” (cutaneous larva migrans)
How do hookworms cause pulmonary lesions?
Filariform larvae break through the pulmonary capillaries & enter the alveoli, which may lead to bronchitis & bronchopneumonia.
