Cryptosporidium parvum
   

1. Name of the Organism: Cryptosporidium parvum	Cryptosporidium parvum, a single-celled animal, i.e., a protozoa, is an obligate intracellular parasite. It has been given additional species names when isolated from different hosts. It is currently thought that the form infecting humans is the same species that causes disease in young calves. The forms that infect avian hosts and those that infect mice are not thought capable of infecting humans. Cryptosporidium sp. infects many herd animals (cows, goats, sheep among domesticated animals, and deer and elk among wild animals). The infective stage of the organism, the oocyst is 3 um in diameter or about half the size of a red blood cell. The sporocysts are resistant to most chemical disinfectants, but are susceptible to drying and the ultraviolet portion of sunlight. Some strains appear to be adapted to certain hosts but cross-strain infectivity occurs and may or may not be associated with illness. The species or strain infecting the respiratory system is not currently distinguished from the form infecting the intestines.
2. Nature of Acute Disease:	Intestinal, tracheal, or pulmonary cryptosporidiosis.
3. Nature of Disease: CDC Case Definition What is a "Case Definition"? Overview of Public Health Surveillance	Intestinal cryptosporidiosis is characterized by severe watery diarrhea but may, alternatively, be asymptomatic. Pulmonary and tracheal cryptosporidiosis in humans is associated with coughing and frequently a low-grade fever; these symptoms are often accompanied by severe intestinal distress. Infectious dose--Less than 10 organisms and, presumably, one organism can initiate an infection. The mechanism of disease is not known; however, the intracellular stages of the parasite can cause severe tissue alteration.
4. Diagnosis of Human Illness:	Oocysts are shed in the infected individual's feces. Sugar flotation is used to concentrate the organisms and acid fast staining is used to identify them. A commercial kit is available that uses fluorescent antibody to stain the organisms isolated from feces. Diagnosis has also been made by staining the trophozoites in intestinal and biopsy specimens. Pulmonary and tracheal cryptosporidiosis are diagnosed by biopsy and staining.
5. Associated Foods:	Cryptosporidium sp. could occur, theoretically, on any food touched by a contaminated food handler. Incidence is higher in child day care centers that serve food. Fertilizing salad vegetables with manure is another possible source of human infection. Large outbreaks are associated with contaminated water supplies.
6. Relative Frequency of Disease:	Direct human surveys indicate a prevalence of about 2% of the population in North America. Serological surveys indicate that 80% of the population has had cryptosporidiosis. The extent of illness associated with reactive sera is not known.
Summary of Notifiable Diseases, United States, 1997:MMWR 46(54)	Reported cases of Cryptosporidiosis, United States 1997
7. Course of Disease and Complications:	Intestinal cryptosporidiosis is self-limiting in most healthy individuals, with watery diarrhea lasting 2-4 days. In some outbreaks at day care centers, diarrhea has lasted 1 to 4 weeks. To date, there is no known effective drug for the treatment of cryptosporidiosis. Immunodeficient individuals, especially AIDS patients, may have the disease for life, with the severe watery diarrhea contributing to death. Invasion of the pulmonary system may also be fatal.
8. Target Populations:	In animals, the young show the most severe symptoms. For the most part, pulmonary infections are confined to those who are immunodeficient. However, an infant with a presumably normal immune system had tracheal cryptosporidiosis (although a concurrent viremia may have accounted for lowered resistance). Child day care centers, with a large susceptible population, frequently report outbreaks.
9. Food Analysis:	The 7th edition of FDA's Bacteriological Analytical Manual will contain a method for the examination of vegetables for Cryptosporidium sp.
10. Selected Outbreaks:	Literature references can be found at the links below.
MMWR 47(40):1998	This report summarizes the investigation of a large outbreak of cryptosporidiosis associated with exposure to a water sprinkler fountain at the Minnesota Zoo. The initial cases were not diagnosed as cryptosporidiosis by the health-care system despite patients seeking care, underscoring the need for increased awareness of cryptosporidiosis and routine laboratory diagnostic practices among health-care providers.
MMWR 47(27):1998	On December 29, 1997, the Spokane Regional Health District received reports of acute gastroenteritis among members of a group attending a dinner banquet catered by a Spokane restaurant on December 18. The illness was characterized by a prolonged (3-9 days) incubation period and diarrhea, which led public health officials to suspect a parasitic cause of the illness. Eight of 10 stool specimens obtained from ill banquet attendees were positive for Cryptosporidium using both modified acid-fast and auramine-rhodamine staining of concentrated specimens.
MMWR 46(16):1997	To improve disease reporting and identify exposures associated with infection, New York City designated cryptosporidiosis a reportable disease in January 1994, and the New York City Department of Health (NYCDOH) initiated active surveillance in November 1994. Each of the clinical laboratories are routinely contacted (usually monthly) for reports of new cases, and each case is investigated by telephone interview and/or chart review. Of the 289 cases of cryptosporidiosis reported in New York City during 1994, most (72%) occurred among men and among persons aged 20-44 years (63%).
MMWR 46(01):1997	In October 1996, unpasteurized apple cider or juice was associated with Cryptosporidium parvum infections in the Northeast. Apple cider is a traditional beverage produced and consumed in the fall. Cider often is manufactured locally at small cider mills where apples are crushed in presses, and the cider frequently is not pasteurized before sale.
MMWR 45(36):1996	On September 29, 1995, the Minnesota Department of Health (MDH) received reports of acute gastroenteritis among an estimated 50 attendees of a social event in Blue Earth County on September 16. This report summarizes the epidemiologic and laboratory investigations of the outbreak, which indicate the probable cause for this foodborne outbreak was Cryptosporidium parvum.
MMWR 45(21):1996	On July 27, 1995, the Alachua County Public Health Unit (ACPHU) in central Florida was notified of an outbreak of gastroenteritis among children and counselors at a day camp on the grounds of a public elementary school. This report summarizes the outbreak investigation, which implicated Cryptosporidium parvum as the causative agent and underscores the role of contaminated water as a vehicle for transmission of this organism.
MMWR 43(31):1994	In March and April 1993, an outbreak of cryptosporidiosis in Milwaukee resulted in diarrheal illness in an estimated 403,000 persons. Following that outbreak, testing for Cryptosporidium in persons with diarrhea increased substantially in some areas of Wisconsin; by August 1, 1993, three of six clinical laboratories in Dane County were testing routinely for Cryptosporidium as part of ova and parasite examinations. In late August 1993, the Madison Department of Public Health and the Dane County Public Health Division identified two clusters of persons with laboratory-confirmed Cryptosporidium infection in Dane County (approximately 80 miles west of Milwaukee).
MMWR 43(36):1994	On December 6, 1993, water-treatment plant operators in the District of Columbia (DC) began to have difficulty maintaining optimal filter effectiveness. On December 7, filter performance worsened, and levels of turbidity (i.e., small suspended particles) exceeded those permitted by U.S. Environmental Protection Agency (EPA) standards. On December 8, DC residents were advised to boil water intended for drinking because of high municipal water turbidity that may have included microbial contaminants. Although adequate chlorination of the DC municipal water was maintained throughout the period of increased turbidity, the parasite Cryptosporidium parvum is highly resistant to chlorination.
MMWR 39(20):1990	From July 13 through August 14, 1988, 44 persons in five separate swimming groups developed a gastrointestinal illness after using a swimming pool in Los Angeles County. The outbreak began several days after an unintentional human defecation in the pool during the first week of July. When the outbreak was reported to the Los Angeles County Department of Health Services (LACDHS) in early August, LACDHS initiated an epidemiologic investigation.
MMWR 36(33):1987	Between July 1 and October 1, 1986, 78 laboratory-confirmed cases of cryptosporidiosis were reported to the Office of Epidemiology at the New Mexico Health and Environment Department. Because the source of infection in these cases was unclear, investigators conducted a case-control study to establish risk factors for infection.
MMWR 33(42):1984	During 1984, CDC has received several reports of cryptosporidiosis among children attending day-care centers. Seven investigations conducted in five states are summarized.
Morbidity and Mortality Weekly Reports	For more information on recent outbreaks see the CDC.
11. Education and Background Resources:	Literature references can be found at the links below.
Loci index for genome Cryptosporidium parvum	Available from the GenBank Taxonomy database, which contains the names of all organisms that are represented in the genetic databases with at least one nucleotide or protein sequence.
FAQ's	Fact Sheet: Cryptosporidiosis
Control and Prevention	Cryptosporidiosis Control and Prevention
Child Care	The ABCs of Safe and Healthy Child Care: Cryptosporidiosis in the Child Care Setting
Cleaning and Disinfecting	The ABCs of Safe and Healthy Child Care: Cleaning and Disinfection
HIV/AIDS	Cryptosporidiosis: A Guide for Persons with HIV/AIDS
Source of Infection	Cryptosporidiosis: Sources of Infection and Guidelines for Prevention
Emerging Infectious Disease 1(2)1995	Waterborne Cryptosporidiosis Threat Addressed
Emerging Infectious Disease 3(1)1997	Cryptosporidiosis: An Emerging, Highly Infectious Threat
Emerging Infectious Disease 3(4)1997	Genetic Polymorphism Among Cryptosporidium parvum isolates: Evidence of Two Distinct Human Transmission Cycles
FSIS Parasites and Foodborne Illness Resource page	Cryptosporidium parvum, cause of the disease cryptosporidiosis (KRIP-toe-spo-RID-e-O-sis), is a one-celled, microscopic parasite, and a significant cause of waterborne illness worldwide. It is found in the intestines of many herd animals including cows, sheep, goats, deer, and elk.
12. Molecular Structural Data:	None currently available.
13. FDA Regulations or Activity:
Bacteriological Analytical Manual.	Current recovery methods are published in this FDA methodology reference. The FDA continues to actively develop and improve methods of recovering parasitic protozoa and helminth eggs from foods.

CDC/MMWR

The CDC/MMWR link will provide a list of Morbidity and Mortality Weekly Reports at CDC relating to this organism or toxin. The date shown is the date the item was posted on the Web, not the date of the MMWR. The summary statement shown are the initial words of the overall document. The specific article of interest may be just one article or item within the overall report.

NIH/PubMed

The NIH/PubMed button at the top of the page will provide a list of research abstracts contained in the National Library of Medicine's MEDLINE database for this organism or toxin.

AGRICOLA

The AGRICOLA button will provide a list of research abstracts contained in the National Agricultural Library database for this organism or toxin.

mow@cfsan.fda.gov
January 1992 with periodic updates

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