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Cryptosporidium parvum - Pathogen Safety Data Sheet

SECTION I - INFECTIOUS AGENT

NAME: Cryptosporidium parvum

SYNONYM OR CROSS REFERENCE: Cryptosporidiosis Footnote 1Footnote 2, crypto.

CHARACTERISTICS: Cryptosporidium parvum is an intracellular protozoan parasite of the family Cryptosporidiidae and phylum Apicomplexa Footnote 1Footnote 3.  It has a complex lifecycle with sexual and asexual cycles taking place in a single host Footnote 4. Oocysts are thick-walled and are the extracellular and environmental stage Footnote 1Footnote 3. Oocysts are 4-6 μm, nearly spherical, which when ingested by the host, excyst within the lumen of the small intestine to release four infective sporozoites and invade surrounding cells Footnote 1Footnote 3. Sporozoites become trophozoites and subsequently type 1 meronts which reproduce asexually and release type 1 merozoites Footnote 4. Type 1 meronts develop into type 2 meronts and release type 2 merozoites which initate the sexual cycle Footnote 4.

SECTION II - HAZARD IDENTIFICATION

PATHOGENICITY/TOXICITY: Infection causes acute gastroenteritis. Symptoms include diarrhea without red blood cells, abdominal pain, cramps, fever, vomiting, myalgia, flatulence, nausea, anorexia, malaise, and fatigue Footnote 5-7. In immunocompetent individuals, illness is self-limiting with symptoms lasting for up to three weeks Footnote 5. Immunocompromised individuals can develop prolonged and chronic cryptosporidiosis Footnote 5. Cryptosporidiosis in immunocompromised patients may lead to more severe clinical manifestations such as severe weight loss, cholangitis, pancreatitis, sclerosing cholangitis, and liver cirrhosis, and has also been associated with an increased rate of morbidity and mortality Footnote 5. This organism is categorized as a Class B bioterrorism agent by the U.S. Department of Homeland Security Footnote 8

EPIDEMIOLOGY: C. parvum occurs worldwide and is ubiquitous in the environment Footnote 1Footnote 9. Cryptosporidiosis is in the top five most common causes of infectious diarrhea around the globe Footnote 9. Prevalence varies based on climate and level of development, accounting for 0.1-2% of diarrheal illness in cooler and developed areas and 0.5-10% in warmer and developing countries Footnote 9. Settings involving close contact with infected persons, including day-care centres, which increase transmission Footnote 10. Outbreaks have been associated with contaminated food, drinking, and recreational water.  One outbreak linked to contaminated drinking water affected over 400,000 individuals in Milwaukee, Wisconsin Footnote 3.

HOST RANGE: Humans, 152 species of mammals, fish, amphibians, reptiles, and birds Footnote 3Footnote 9.

INFECTIOUS DOSE: The median infectious dose in healthy adult volunteers is 132 oocysts Footnote 6. However, the infectious dose for humans is as low as 1-5 oocysts Footnote 11Footnote 12. Infectious dose is dependent on the immune status of the host, with immunodeficient persons being much more susceptible Footnote 13.

MODE OF TRANSMISSION: Transmitted through the fecal-oral route, direct contact with infected humans or animals, contaminated food or water and aerosols Footnote 1Footnote 2Footnote 4

INCUBATION PERIOD: 7 to 10 days Footnote 9.

COMMUNICABILITY: Highly contagious. Human-to-human transmission is common Footnote 5. Oocysts can be excreted up to 50 days after cessation of diarrhea Footnote 10.

SECTION III - DISSEMINATION

RESERVOIR: Environment and many mammalian species Footnote 9.

ZOONOSIS: Yes – Mainly from domestic and wild ruminants Footnote 1.

VECTORS: Flying insects can act as a mechanical vector Footnote 14.

SECTION IV - STABILITY AND VIABILITY

DRUG SUSCEPTIBILITY: Susceptible to nitazoxanide Footnote 1 (not available in Canada).

SUSCEPTIBILITY TO DISINFECTANTS: C. parvum is susceptible to high concentration (> 6%) of hydrogen peroxide and ethylene oxide, ozone Footnote 15. It is resistant to low concentration of hydrogen peroxide, peracetic acid, sodium hypochlorite, phenolic, quaternary ammonium compound, 2% glutaraldehyde, ortho-phtalaldehyde, and 70% ethanol Footnote 16.

PHYSICAL INACTIVATION: Inactivated by moist heat Footnote 17(e.g. 121°C for 18 minutes), freezing (-70°C for seconds or -20°C for 24 hours), desiccation Footnote 3Footnote 16, and UV light Footnote 18. Use of “absolute” 1 μm filters.

SURVIVAL OUTSIDE HOST: Can survive for 6 months at 20°C in the environment Footnote 3.

SECTION V - FIRST AID / MEDICAL

SURVEILLANCE: Detection usually by direct microscopic observation of oocysts in stool specimens. Nucleic acid and antigen detection methods have also been developed Footnote 1Footnote 2Footnote 5.

FIRST AID/TREATMENT: Illness is generally self-limiting in immunocompetent patients.  Rehydration and electrolyte therapy may be used in cases with severe diarrhea. Nitazoxanide is approved for treatment of cryptosporidiosis in children aged 1 to 10 years in the USA Footnote 19. It has also showed promise in immunocompromised individuals Footnote 1Footnote 2. Immunocompromised patients are often treated with paromomycin, letrazuril and azithromycin Footnote 2. Highly active antiretroviral therapy (HAART) is currently considered the best treatment option for life-threatening cryptosporidiosis in AIDS patients Footnote 1Footnote 2.

IMMUNIZATION: None

PROPHYLAXIS: None

SECTION VI - LABORATORY HAZARDS

LABORATORY-ACQUIRED INFECTIONS: Yes, at least 16 cases of cryptosporidiosis have been reported Footnote 20.

SOURCES/SPECIMENS: Stool, intestinal biopsy specimens from humans or animals and environmental water Footnote 1.

PRIMARY HAZARDS: Ingestion of oocysts, parenteral inoculation, contact with aerosolized droplets Footnote 4Footnote 21.

SPECIAL HAZARDS: Contact with naturally and experimentally infected animals Footnote 4.

SECTION VII - EXPOSRE CONTROLS / PERSONAL PROTECTION

RISK GROUP CLASSIFICATION: Risk Group 2.

CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures Footnote 22.

PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes Footnote 22.

OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities Footnote 22.

SECTION VIII - HANDLING AND STORAGE

SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply an appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up Footnote 22.

DISPOSAL:Decontaminate all wastes that contain or have come in contact with the infectious organism by autoclave, chemical disinfection, gamma irradiation, or incineration before disposing Footnote 22.

STORAGE: The infectious agent should be stored in leak-proof containers that are appropriately labelled Footnote 22.

SECTION IX - REGULATORY AND OTHER INFORMATION

REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.

UPDATED: December 2011

PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada.
Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.

Copyright © Public Health Agency of Canada, 2011 Canada 

REFERENCES

Footnote 1
Xiao, L., & Cama, V. (2007). Cryptosporidium. In P. R. Murray (Ed.), Manual of Clinical Microbiology (9th ed., pp. 2122-2132). Washington D.C.: ASM Press.
Footnote 2
Krauss, H., Weber, A., Appel, M., Enders, B., Isenberg, H. D., Scheifer, H. G., Slenczka, W., von Graevenitz, A., & Zahner, H. (2003). Parasitic Zoonoses. Zoonoses: Infectious Diseases Transmissible from Animals to Humans (Third ed., pp. 278-80). Washington, D.C.: ASM Press.
Footnote 3
Fayer, R., Morgan, U., & Upton, S. J. (2000). Epidemiology of Cryptosporidium: Transmission, detection and identification. International Journal for Parasitology, 30(12-13), 1305-1322.
Footnote 4
Casemore, D. P. (2009). Epidemiological aspects of human cryptosporidiosis. Epidemiology and Infection, 104(01), 1-28.
Footnote 5
Chalmers, R. M., & Davies, A. P. (2010). Minireview: Clinical cryptosporidiosis. Experimental Parasitology, 124(1), 138-146.
Footnote 6
DuPont, H. L., Chappell, C. L., Sterling, C. R., Okhuysen, P. C., Rose, J. B., & Jakubowski, W. (1995). The infectivity of Cryptosporidium parvum in healthy volunteers. New England Journal of Medicine, 332(13), 855-859.
Footnote 7
Kanarat, S. (2004). Symptoms, treatments, and health consequences of waterborne zoonotic diseases. Waterborne Zoonoses: Identification, Causes, and Control, , 136.
Footnote 8
U.S. Department of Homeland Security. (2004). Biological Attack. Human Pathogens, Biotoxins, and agricultural threats. Retrieved November, 2011, from http://www.dhs.gov/xlibrary/assets/prep_biological_fact_sheet.pdf
Footnote 9
Boatright, D. T., & Greenfield, R. A. (2005). Bioterrorism and Threats to Water Safety: Cholera and Cryptosporidiosis. In M. S. Bronze, & R. A. Greenfield (Eds.), Biodefense: Principles and Pathogens (pp. 587-617). Norfolk UK: Horizon Bioscience.
Footnote 10
Yoder, J. S., & Beach, M. J. (2007). Cryptosporidiosis surveillance—United States, 2003–2005. MMWR Surveill Summ, 56, 1-10.
Footnote 11
Guerrant, R. L. (1997). Cryptosporidiosis: an emerging, highly infectious threat. Emerging Infectious Diseases, 3(1), 51-57.
Footnote 12
Gilles, H. M. (1999). Cryptosporidiosis. Protozoan Diseases. (pp. 592-606). New York: Arnold and Oxford University Press.
Footnote 13
Goldstein, S. T., Juranek, D. D., Ravenholt, O., Hightower, A. W., Martin, D. G., Mesnik, J. L., Griffiths, S. D., Bryant, A. J., Reich, R. R., & Herwaldt, B. L. (1996). Cryptosporidiosis: an outbreak associated with drinking water despite state-of-the-art water treatment. Annals of Internal Medicine, 124(5), 459-468.
Footnote 14
Graczyk, T. K., Cranfield, M. R., Fayer, R., & Bixler, H. (1999). House flies (Musca domestica) as transport hosts of cryptosporidium parvum. American Journal of Tropical Medicine and Hygiene, 61(3), 500-504.
Footnote 15
Korich, D. G., Mead, J. R., Madore, M. S., Sinclair, N. A., & Sterling, C. R. (1990). Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability. Applied and Environmental Microbiology, 56(5), 1423-1428.
Footnote 16
Barbee, S. L., Weber, D. J., Sobsey, M. D., & Rutala, W. A. (1999). Inactivation of Cryptosporidium parvum oocyst infectivity by disinfection and sterilization processes. Gastrointestinal Endoscopy, 49(5), 605-611.
Footnote 17
Anderson, B. C. (1985). Moist heat inactivation of Cryptosporidium sp. American Journal of Public Health, 75(12), 1433-1434.
Footnote 18
Dawson, D. (2005). Foodborne protozoan parasites. International Journal of Food Microbiology, 103(2), 207-227.
Footnote 19
Cabada, M. M., & White, A. C.,Jr. (2010). Treatment of cryptosporidiosis: do we know what we think we know? Current Opinion in Infectious Diseases, 23(5), 494-499. doi:10.1097/QCO.0b013e32833de052
Footnote 20
Herwaldt, B. L. (2006). Protozoa and Helminths. In D. O. Fleming, & D. L. Hunt (Eds.), Biological Safety: Principles and Practices (4th ed., pp. 115-161). Washington DC: ASM Press.
Footnote 21
Collins, C. H., & Kennedy, D. A. (1999). Decontamination. Laboratory-acquired Infections: History, incidence, causes and prevention (Fourth ed., pp. 160-186, 170-176). Oxford, UK: Butterwroth Heinemann.
Footnote 22
Public Health Agency of Canada. (2004). In Best M., Graham M. L., Leitner R., Ouellette M. and Ugwu K. (Eds.), Laboratory Biosafety Guidelines (3rd ed.). Canada: Public Health Agency of Canada.