Hookworm

Question 1

Hookworm infection - causative organisms

Answer 1

Nematode [roundworm]

Ancyclostoma duodenale, necator americanus = human definitive host
Ancyclostoma ceylanicum = human accidental host

Question 2

Hookworm - adult size

Answer 2

1cm

Question 3

Hookworm - lifecycle

Answer 3

Eggs passed in stool
Larvae hatch 1-2 days and become freeliving in soil - released rhabditiform larvae grow
After 5-10 days - filariform larvae
Larvae penetrate skin and are carried through vessels to heart and lungs
Penetrate pulmonary alveoli, ascend bronchial tree to pharynx and are swallowed
Larvae reach jejunum where they mature into adults

Question 4

Hookworm - early clinical presentation

Answer 4

Cutaneous larva migrans [larva migration in skin:
-Intensely pruritis, creeps along for days
-Track formed due to inflammatory allergic [IgE mediated] response to microscopic larva

Respiratory - cough, wheeze [can be asymptomatic]
-Rare - eosinophilic pneumonitis [Loeffler’s syndrome] = IgE mediated immune response to larvae in lungs

Question 5

Hookworm - late clinical presentation

Answer 5

Correlates to worm burden
-Often asymptomatic
-Adults rarely pass spontaneously
-Occasionally nausea, abdominal pain and diarrhoea
-Anaemia if high worm burden

Question 6

Hookworm - diagnosis

Answer 6

Clinical - cutaneous larva migrans
Stool for ova, cysts and parasites

Question 7

Hookworm - treatment

Answer 7

Ivermectin or albendazole