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Volume 10, Number 4—April 2004
Dispatch

Human Challenge Pilot Study with Cyclospora cayetanensis

Edith M. Alfano-Sobsey*Comments to Author , Mark L. Eberhard†, John R. Seed‡, David J. Weber‡, Kimberly Y. Won†, Eva K. Nace†, and Christine L. Moe§
Author affiliations: *Office of Public Health Preparedness and Response, Raleigh, North Carolina, USA; †Centers for Disease Control and Prevention, Atlanta, Georgia, USA; ‡University of North Carolina, Chapel Hill, North Carolina, USA; §Emory University, Atlanta, Georgia, USA

Main Article

Table

Inoculum treament and challenge conditions from the Cyclospora human challenge studya

Volun-teer Oocysts source (no.) Oocysts ingested, mean ± SD (% sporulated) Inoculum disinfectionb,c Storage medium until dosing Total storage (mo)d Inoculum ingestion medium and conditions
1
 Haiti (3)
 647 ± 183 (82)
 Bleach and thiosulfate (pre-storage)
 Sterile water
 6+
 Sterile water, then light lunch
2
 Haiti (3)
 203 ± 22 (69)
 Bleach and thiosulfate (pre-storage)
 Sterile water
 7+
 Sterile water, then light lunch
3
 Haiti (1)
 884 ± 22 (96)
 Bleach and thiosulfate (pre-storage)
 Sterile water
 10
 Sterile water, then light lunch
4
 MO, USA (1)
 4,851 ± 545 (71)
 Bleach only; wash on dosing day
 Sterile PBS
 6+
 Sterile water, with a chicken salad meal
5
 MO, USA (1)
 1,815 ± 249 (67)
 Thiosulfate only; wash on dosing day
 Sterile PBS
 7
 Sterile water, with a chicken salad meal
6
 MO, USA (1)
 4,916 ± 1,153 (67)
 Bleach and thiosulfate (pre-storage)
 Sterile PBS
 7+
 Sterile water, with a chicken salad meal
7 GA, USA (1) 48,884 ± 15,345 (94) Bleach and thiosulfate 3 days predosing 2.5% dichromate 5 Raspberries, then light lunch

aMO, Missouri; GA, Georgia; PBS, phosphate-buffered saline.
bHousehold bleach (5.25% sodium hypochlorite) was used for disinfection, and sodium thiosulfate (0.01%–0.1%) was used to inactivate residual bleach in the inocula.
cFor safety testing laboratory details, contact corresponding author.
dTime in storage from stool collection until volunteer dosing date, includes time oocysts were exposed to potassium dichromate in stool until sporulation plus the time the oocysts were in storage media after they were extracted from the stool specimens.

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Page created: February 09, 2011
Page updated: February 09, 2011
Page reviewed: February 09, 2011
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
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