Hookworms - Intestinal Nematodes

Distribution between 45°N and 30°S, infecting about 9 billion people.

Infection of human:
-Necator americanus, ancylostoma duodenale.
Infection of other species:
-Ancylostoma caninum & ancylostoma braziliense.
-Ancylostoma ceylanicum & ancylostoma malayanium.

Copulatory bursa:
-For reproduction, attaches to the females vagina.

Transmission:
-Penetration of skin by filariform larvae(L3, infective)
-Ingesting of infective larvae in A. duodenale.
-Transmammary transmission of larvae in A. duodenale.

Diagnostic stage -> Egg in feaces.
Infective stage -> Filariform larva(L3).

Migrates similar to Ascaris lumbricoides.

Clinical pathology:
-Ground itch:
--Skin reaction at site of larval penetration.
--Feeling stinging.
--Followed by irration, erythea, oedema & papulovesicular eruption.
-Creeping eruptions:
--A. braziliense and A.caninum wandering through the cutaneous layer.
--cutaneous larva migrans cause intense irritation and inflammation.
--Most larvae die in the skin.

Migration of F-form larvae(L3):
-During invasion of circulation:
--Usually no ill-effect.
-During migration through the lung:
--pneumonitis with cough, wheeze, feever, transient X-ray shadows.
--Not as severe as Ascaris.

Causes hookworm anemia(HWA):
-Losses of blood, iron and proteins.
-Occasionally associated with folate deficiency.

Worms move every 4-6 hours -> blood leaking while hooking on different places.

Laboratory diagnosis:
-Direct smear for eggs (Oval-shaped, thin shell).
-Egg culture for 1st stage larva(L1).