The infectivity of Cryptospordium parvum in healthy volunteers

Herbert L. DuPont, Cynthia L. Chappell, Charles R Sterling, Pablo C. Okhuysen, Joan B. Rose, Walter Jakubowski

Research output: Contribution to journalArticle

683 Citations (Scopus)

Abstract

Background. Small numbers of Cryptosporidium parvum oocysts can contaminate even treated drinking water, and ingestion of oocysts can cause diarrheal disease in normal as well as immunocompromised hosts. Since the number of organisms necessary to cause infection in humans is unknown, we performed a study to determine the infective dose of the parasite in healthy adults. Methods. After providing informed consent, 29 healthy volunteers without evidence of previous C. parvum infection, as determined by the absence of anti-cryptosporidium-specific antibodies, were given a single dose of 30 to 1 million C. parvum oocysts obtained from a calf. They were then monitored for oocyst excretion and clinical illness for eight weeks. Household contacts were monitored for secondary spread. Results. Of the 16 subjects who received an intended dose of 300 or more oocysts, 14 (88 percent) became infected. After a dose of 30 oocysts, one of five subjects (20 percent) became infected, whereas at a dose of 1000 or more oocysts, seven of seven became infected. The median infective dose, calculated by linear regression, was 132 oocysts. Of the 18 subjects who excreted oocysts after the challenge dose, 11 had enteric symptoms and 7 (39 percent) had clinical cryptosporidiosis, consisting of diarrhea plus at least one other enteric symptom. All recovered, and there were no secondary cases of diarrhea among household contacts. Conclusions. In healthy adults with no serologic evidence of past infection with C. parvum, a low dose of C. parvum oocysts is sufficient to cause infection.

Original languageEnglish (US)
Pages (from-to)855-859
Number of pages5
JournalNew England Journal of Medicine
Volume332
Issue number13
StatePublished - Mar 30 1995

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Oocysts
Healthy Volunteers
Cryptosporidium parvum
Infection
Diarrhea
Cryptosporidiosis
Cryptosporidium
Immunocompromised Host
Informed Consent
Drinking Water
Linear Models
Parasites
Eating

ASJC Scopus subject areas

  • Medicine(all)

Cite this

DuPont, H. L., Chappell, C. L., Sterling, C. R., Okhuysen, P. C., Rose, J. B., & Jakubowski, W. (1995). The infectivity of Cryptospordium parvum in healthy volunteers. New England Journal of Medicine, 332(13), 855-859.

The infectivity of Cryptospordium parvum in healthy volunteers. / DuPont, Herbert L.; Chappell, Cynthia L.; Sterling, Charles R; Okhuysen, Pablo C.; Rose, Joan B.; Jakubowski, Walter.

In: New England Journal of Medicine, Vol. 332, No. 13, 30.03.1995, p. 855-859.

Research output: Contribution to journalArticle

DuPont, HL, Chappell, CL, Sterling, CR, Okhuysen, PC, Rose, JB & Jakubowski, W 1995, 'The infectivity of Cryptospordium parvum in healthy volunteers', New England Journal of Medicine, vol. 332, no. 13, pp. 855-859.
DuPont HL, Chappell CL, Sterling CR, Okhuysen PC, Rose JB, Jakubowski W. The infectivity of Cryptospordium parvum in healthy volunteers. New England Journal of Medicine. 1995 Mar 30;332(13):855-859.
DuPont, Herbert L. ; Chappell, Cynthia L. ; Sterling, Charles R ; Okhuysen, Pablo C. ; Rose, Joan B. ; Jakubowski, Walter. / The infectivity of Cryptospordium parvum in healthy volunteers. In: New England Journal of Medicine. 1995 ; Vol. 332, No. 13. pp. 855-859.
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