Experimental Infection of Hookworm-naïve Adults With Dermally-applied Infectious Necator Americanus Hookworm Larvae

Open-label, dose-escalation clinical study in healthy, hookworm-naïve adults: * Study site: George Washington Medical Faculty Associates, Washington, DC * Number of participants: up to 35 in 3 cohorts In Cohort 1, ten (10) volunteers will receive an inoculum of 25 infectious Necator americanus larvae. In Cohort 2, ten (10) volunteers will receive an inoculum of 50 infectious Necator americanus larvae. In the optional Cohort 3, fifteen (15) volunteers will receive an inoculum of 75 infectious Necator americanus larvae. The cohorts will be enrolled in a staggered fashion with safety data assessed prior to larval dose escalation. Cohort 2 will be inoculated no earlier than 8 weeks after the last volunteer is inoculated in Cohort 1. The optional Cohort 3 will be inoculated no sooner than 8 weeks after the last volunteer is inoculated in Cohort 2. Cohort 3 will be enrolled only if the tolerability of the experimental infection of Cohort 2 is acceptable and does not result in significant adverse events. Within each cohort, after Study Day 70, but before Study Day 77, up to 5 volunteers will undergo capsule endoscopy in order to visualize and count adult N. americanus hookworms residing in the intestine. Informed consent for capsule endoscopy will be obtained separately from the primary study, and agreement or refusal will not impact on a subject's eligibility to enroll or continue participation in the primary study. Three months after larval administration, or at the time of study withdrawal, all participants will receive a 3-dose treatment of albendazole (400 mg per dose) for clearance of experimental infection. * Larval inoculum schedule: Study Day 0 (single application) * Route: applied to intact skin on the volar aspect of forearm * Doses of N. americanus Larval Inoculum to be tested: 25, 50 and 75 infectious larvae (high dose optional) * Study duration: 6 months per study participant; total duration of the study estimated at approximately 13 months * Anthelmintic treatment: 3 months post larval inoculum, or at study withdrawal, 3-dose treatment with 400 mg albendazole