Necator americanusReaction after penetration of

infective larvae (iL3)

Prof Rick Speare

Tropical Health Solutionsrickspeare@gmail.com

22 July 2012

101 iL3 have been placed on a pad under a bandage on the ventral surface of the wrist*

• Itching starts within 2 mins as iL3 begin to penetrate the skin

* 101 iL3 was too high!

12 hr post-infection

• Penetration site is itchy• Indistinct areas of erythema visible

1 day post-infection

• Erythema has increased• Papules are forming

2 days post-infection

• Multiple papules formed• Coallesced due to the large number of iL3 used

4 days post-infection

• Papules are increasing in size still

6 days post-infection

• Some papules are starting to vesiculate

7 days post-infection

8 days post-infection

9 days post-infection

10 days post-infection

• Vesiculation progresses

11 days post-infection

• At last! Signs that the lesions will disappear!

12 days post-infection

15 days post-infection

20 days post-infection

• Three weeks for the penetration reaction to resolve is 3 times longer than normal

Useful sources

• All images were original made by Rick Speare

• For additional information on experimental infections:

• Croese J, Speare R, Wood M, Melrose W. Allergy controls the population density of Necator americanus in the small intestine. Gastroenterology 2006;131(2):402-409.

• Croese J, Speare R. Intestinal allergy expels hookworms: seeing is

believing. Trends in Parasitology 2006;22(12):547-550.• Hookworms at Tropical Health Solutions