Skip to main content

Cryptosporidiosis in Wisconsin: A case-control study of post-outbreak transmission

  • P. Osewe (a1), D. G. Addiss (a2), K. A. Blair (a3), A. Hightower (a2), M. L. Kamb (a1) and J. P. Davis (a4)...

During March–April 1993, an estimated 403000 residents of the 5-county greater Milwaukee, Wisconsin area developed cryptosporidiosis after drinking contaminated municipal water. Although the number of cases dropped precipitously after the implicated water plant closed on 9 April, cases continued to occur. To investigate risk factors for post-outbreak cryptosporidiosis, 33 Milwaukee-area residents who had laboratory-confirmed Cryptosporidium infection with onset of diarrhoea between 1 May and 27 June 1993 were interviewed by telephone. Of these, 28(85%) had onset of diarrhoea during May, 12(36%) had watery diarrhoea during the outbreak, and 5 (15%) were HIV-infected. In a neighbourhood-matched case-control study, immunosuppression (matched odds ratio (MOR) not calculable, 95 % confidence interval (CI) 3·0, infinity) and having a child less than 5 years old in the household (MOR = 17·0, CI 2·0, 395·0) were independently associated with infection. When persons who had diarrhoea during the outbreak were excluded, immunosuppression remained significantly associated with illness (MOR not calculable, CI 1·6, infinity). Cryptosporidium transmission continued after this massive waterborne outbreak but decreased rapidly within 2 months.

Corresponding author
* David Addiss, Division of Parasitic Diseases, Mailstop F-22, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA.
Hide All
1.Casemore DP. Epidemiological aspects of human cryptosporidiosis. Epidemiol Infect 1990; 104: 128.
2.CDC. Assessing the public health threat associated with waterborne cryptosporidiosis: Report of a workshop. MMWR 1995; 44 (No. RR-6): 119.
3.Public Health Laboratory Service Study Group. Cryptosporidiosis in England and Wales: prevalence and clinical and epidemiologic features. BMJ 1990; 300: 774–7.
4.MacKenzie WR, Hoxie NJ, Proctor ME, et al. A massive waterborne outbreak of Cryptosporidium infection transmitted through the public water supply. N Engl J Med 1994; 331: 161–7.
5.D'Antonio RG, Winn RE, Taylor JP, et al. A waterborne outbreak of cryptosporidiosis in normal hosts. Ann Intern Med 1985; 103: 886–8.
6.Hayes EB, Matte TD, O'Brien TR, et al. Large community outbreak of cryptosporidiosis due to contamination of a filtered public water supply. N Engl J Med 1989; 320: 1372–6.
7.Millard PS, Gensheimer KF, Addiss DG, et al. An outbreak of cryptosporidiosis from fresh-pressed apple cider. JAMA 1994; 272: 1593–6.
8.MacKenzie WR, Schell WL, Blair KA, et al. Massive waterborne outbreak of Cryptosporidiosis, Milwaukee, Wisconsin: Recurrence of illness and risk of secondary transmission. Clin Infect Dis 1995; 21: 5762.
9.Ungar BLP. Cryptosporidiosis in humans (Homo sapiens). In: Dubey JP, Speer CA, Fayer R, eds. Cryptosporidiosis of man and animals. Boca Raton, Florida: CRC Press, 1990: 5982.
10.Dupont HL, Chappell CL, Sterling CR, Okhuysen PC, Rose JB, Jakubowski W. The infectivity of Cryptosporidium parvum in healthy volunteers. N Engl J Med 1995; 332: 855–9.
11.Flanigan T, Whalen C, Turner J, et al. Cryptosporidium infection and CD4 counts. Ann Intern Med 1992; 116: 840–2.
12.McGowan I, Hawkins AS, Weller IVD. The natural history of cryptosporidial diarrhoea in HIV-infected patients. AIDS 1993; 7: 349–54.
13.Freidank H, Kist M. Cryptosporidia in immunocompetent patients with gastroenteritis. Eur J Clin Microbiol Infect Dis 1987; 6: 56–9.
14.Pitlik SD, Fainstein V, Garza D, et al. Human cryptosporidiosis: spectrum of disease. Report of six cases and review of the literature. Arch Intern Med 1983; 33: 98108.
15.Schlesselman JJ. Case-control studies: Design, conduct, and analysis. New York: Oxford University Press, 1982.
16.Gallaher MM, Herndon JL, Nims LJ, Sterling CR,Grabowski DJ, Hull JF. Cryptosporidiosis and surface water. Am J Public Health 1989; 79: 3942.
17.Weinstein P, Macaitis CW, Cameron S. cryptosporidial diarrhoea in South Australia. Med J Aust 1993; 158: 117–9.
18.CDC. Cryptosporidium infections associated with swimming pools – Dane County, Wisconsin, 1993. MMWR 1994; 43: 561–3.
19.MacKenzie WR, Kazmierczak JJ, Davis JP. An outbreak of cryptosporidiosis associated with a resort swimming pool. Epidemiol Infect 1995; 115: 545–53.
20.Cordell RL, Addiss DG. Cryptosporidiosis in child care settings: A review of the literature and recommendations for prevention and control. Pediatr Infect Dis J 1994; 13: 310–7.
21.Ravn P, Lundgren JD, Kjaeldgaard P, et al. Nosocomial outbreak of cryptosporidiosis in AIDS patients. BMJ 1991; 302: 277–80.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Epidemiology & Infection
  • ISSN: 0950-2688
  • EISSN: 1469-4409
  • URL: /core/journals/epidemiology-and-infection
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Full text views

Total number of HTML views: 0
Total number of PDF views: 3 *
Loading metrics...

Abstract views

Total abstract views: 66 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 20th January 2018. This data will be updated every 24 hours.