Effect of disinfection of drinking water with ozone or chlorine dioxide on survival of Cryptosporidium parvum oocysts

Demineralized water was seeded with controlled numbers of oocysts of Cryptosporidium parvum purified from fresh calf feces and subjected to different treatments with ozone or chlorine dioxide. The disinfectants were neutralized by sodium thiosulfate, and neonatal mice were inoculated intragastrically and sacrificed 7 days later for enumeration of oocyst production. Preliminary trials indicated that a minimum infection level of 1,000 oocysts (0.1-ml inoculum) per mouse was necessary to induce 100% infection. Treatment of water containing 10(4) oocysts per ml with 1.11 mg of ozone per liter (concentration at time zero [C0]) for 6 min totally eliminated the infectivity of the oocysts for neonatal mice. A level of 2.27 mg of ozone per liter (C0) was necessary to inactivate water containing 5 x 10(5) oocysts per ml within 8 min. Also, 0.4 mg of chlorine dioxide per liter (C0) significantly reduced infectivity within 15 min of contact, although some oocysts remained viable.

[1]  R. Sokal,et al.  Introduction to biostatistics , 1974 .

[2]  T. Haynes,et al.  Complete development of Cryptosporidium in cell culture. , 1984, Science.

[3]  R E Winn,et al.  A waterborne outbreak of cryptosporidiosis in normal hosts. , 1985, Annals of internal medicine.

[4]  W. J. Masschelein,et al.  Experience With Chlorine Dioxide in Brussels, Part 3: Operational Case Studies , 1985 .

[5]  C. Rubin,et al.  Overwhelming watery diarrhea associated with a cryptosporidium in an immunosuppressed patient. , 1976, Gastroenterology.

[6]  W. Masschelein.  Spectrophotometric determination of chlorine dioxide with Acid Chrome Violet K , 1966 .

[7]  S. Pitlik,et al.  Human cryptosporidiosis: spectrum of disease. Report of six cases and review of the literature. , 1983, Archives of internal medicine.

[8]  D. Lindsay,et al.  Infection dynamics of Cryptosporidium parvum (Apicomplexa: Cryptosporiidae) in neonatal mice (Mus musculus). , 1986, The Journal of parasitology.

[9]  P. A. Chapman,et al.  CRYPTOSPORIDIUM AND DRINKING WATER , 1987, The Lancet.

[10]  R. Fayer,et al.  Cryptosporidium spp. and cryptosporidiosis. , 1987, Microbiological reviews.

[11]  W. Masschelein.  Experience With Chlorine Dioxide in Brussels, Part 2: Methods for Controlling Chlorine Dioxide Operation , 1984 .

[12]  I Campbell,et al.  Effect of disinfectants on survival of cryptosporidium oocysts , 1982, Veterinary Record.

[13]  J. Ongerth,et al.  GIARDIA AND CRYPTOSPORIDIUM IN DRINKING WATER , 1987, The Lancet.

[14]  S. Tzipori,et al.  Cryptosporidiosis in animals and humans. , 1983, Microbiological reviews.

[15]  D. Page,et al.  Acute enterocolitis in a human being infected with the protozoan Cryptosporidium. , 1976, Gastroenterology.

[16]  Ordóñez Ng,et al.  Human cryptosporidiosis in the acquired immune deficiency syndrome. , 1983 .

[17]  R. Soave,et al.  Three-step stool examination for cryptosporidiosis in 10 homosexual men with protracted watery diarrhea. , 1983, The Journal of infectious diseases.

[18]  J. Rose,et al.  Occurrence of Cryptosporidium oocysts in sewage effluents and selected surface waters. , 1987, The Journal of parasitology.

[19]  I Campbell,et al.  Evaluation of the effect of two aldehyde-based disinfectants on the infectivity of faecal cryptosporidia for mice. , 1982, Research in veterinary science.

[20]  Willy J Masschelein,et al.  Experience With Chlorine Dioxide in Brussels: Generation of Chlorine Dioxide , 1984 .