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Cryptosporidiosis

What is cryptosporidiosis?

Cryptosporidium is a parasite that causes an intestinal illness referred to as cryptosporidiosis. C. parvum and C. hominis are the species associated with human infection. Cryptosporidiosis is a leading cause of waterborne disease among humans in the U.S., and while cases are reported year-round, infections are most common in the summer and early fall. Cryptosporidium can be found in cattle (especially pre-weaned calves), humans and other domestic animals. 

Signs and symptoms

  • Watery, non-bloody diarrhea
  • Abdominal cramps
  • Low-grade fever
  • Weight loss
  • Vomiting
  • General malaise
  • Nausea

Incubation period

Two to 10 days (usually seven days)

Contagious period and spread

Cryptosporidium is spread by fecal→oral transmission and occurs by ingesting the parasite from the stool of people or animals with infection. People can be exposed to this parasite when they swim in or drink contaminated water, eat contaminated food, come into direct or indirect contact with infected animals, or via person-to-person transmission. The parasite can survive outside the body for two to six months in moist surroundings. 

People are contagious as long as they have the parasite in their intestines and are most contagious when they have diarrhea. Infected animals and people excrete large amounts of parasites in their stool. The infectious dose (the amount a person needs to be exposed to in order to become infected) is considered to be very low.The parasite may be present in the stool for several weeks after symptoms subside. 

Public health reporting requirements

Staff who become aware of a student or staff member with confirmed or suspected Cryptosporidium infection should report the infection to the facility director or school nurse. The facility should report to the state or local public health agency within four days of diagnosis or positive lab result.

If other children or staff are ill with diarrhea, refer them to their health care providers and contact public health as soon as possible as this could be an outbreak. Generally speaking, it is considered an outbreak if there is an increase in the number of ill children and/or staff members at the school or child care center. Suspected outbreaks should be reported to the CDPHE or local health department immediately (within 4 hours), even if the causative agent is not yet know. 

Control of spread

  • Encourage and teach the importance of frequent handwashing and proper hygiene techniques, especially after animal contact, using the toilet, changing diapers, and before eating. After changing diapers, the child’s hands should be washed as well as those of the person changing the diaper. Sample signs showing when and how to wash hands are included on the Department’s child care health regulations webpage under “Preventing illness” and in the hand hygiene section of this website section. Post them or similar signs throughout the child care center or school to remind people to wash their hands. 
  • Promptly sanitize contaminated surfaces (like diaper-changing areas) and other commonly touched surfaces (like toys) and discard food or water if it is thought to be contaminated. (Disease Prevention: The Facility Environment)
  • Chlorine sanitizers (such as bleach) do not kill this organism. A non-chlorine sanitizer should be used to sanitize contaminated articles (such as a 5% ammonia solution or 3% hydrogen peroxide solution for 15 minutes). Heat (140°F for two minutes) will also destroy the organism. Do not mix bleach and ammonia products. 
  • Untreated water (such as water from lakes, ponds, springs, rivers, and streams) should not be used as drinking water unless it is boiled for at least one minute or adequately filtered by using a filter capable of removing particles 0.1 to 1.0 micrometers in diameter. 
  • Avoid swallowing water when swimming. Lakes, streams (and other surface waters), and swimming pools may be contaminated  with Cryptosporidium. Chemical disinfectants, such as chlorine and iodine, are not effective at killing Cryptosporidium. 
  • Avoid drinking raw milk, other unpasteurized dairy products, or unpasteurized apple cider. 
  • Affected individuals should not swim or wade in pools or other recreational water until two weeks after their diarrhea has resolved.
  • Refer to Disease Prevention: Food Safety for information on food safety.
  • Alert possibly exposed family and staff members to watch for symptoms and provide them with prevention tips. See recommendations for caregivers and the family section below.

Treatment

The illness usually resolves in two to three weeks (average of 10 days), but symptoms can come and go for up to 30 days or longer. Some people can be infected without showing any symptoms. The most common symptom is watery diarrhea. Ill people should be given plenty of fluids to prevent dehydration. Healthy children usually get better on their own. However, the infection can be more severe in people with weakened immune systems. People with suppressed immune systems should contact their health care provider. A health care provider may prescribe a medicine such as nitazoxanide, an FDA-approved medication for treatment of cryptosporidiosis.

Exclusion

Child care and preschool 

  • EXCLUDE all infected children and/or caregivers, including food handlers, until 24 hours after diarrhea has resolved, without the use of anti-diarrheal medications.
  • If there are concerns about the child’s hygienic practices, consider obtaining two negative stool tests obtained at least 24 hours apart before the case returns to class. 
  • Ill children should not go to another facility during the period of exclusion.
  • Determine if other children or staff have recently had diarrhea. Children with diarrhea should be excluded, seen by their physician, and submit stool for testing. If other cases in the center are identified, public health may require negative tests for children to return to care.
  • The center should work with public health when considering sending a letter home to parents.
  • Parents and school staff should be reminded that cases should not swim or wade in pools for two weeks after resolution of diarrhea. 

Primary and secondary school

  • EXCLUDE all infected children experiencing symptoms and/or staff until at least 24 hours after diarrhea has resolved.
  • In general, students or staff with cryptosporidiosis who do not have diarrhea and are not otherwise sick may remain in school.
  • If there are concerns about the child’s hygiene (e.g., the case has development disabilities and wears diapers), consider obtaining two negative stool tests at least 24 hours apart before the case returns to class.
  • In rare circumstances, public health may require additional testing before a person with infection can return to work, school, or child care.
  • EXCLUDE affected individuals from food preparation until at least 24 hours after their diarrhea has resolved, or they are cleared by the state or local public health agency.
  • Parents and school staff should be reminded that cases should not swim or wade in pools for two weeks after resolution of diarrhea. 

Role of teachers, caregivers, and family

  • If your child or a child you care for is infected with cryptosporidiosis, follow the advice of the child’s health care provider.
  • Practice good handwashing, especially after changing diapers, going to the bathroom or helping a child to the bathroom, or handling food.
  • Since pets and other animals can carry Cryptosporidium, wash hands after feeding or touching, and make sure that bedding and feeding materials are clean.
  • Clean and disinfect diapering, bathroom, and food preparation areas frequently.
  • Avoid drinking or serving raw milk, unpasteurized dairy products, or unpasteurized cider.
  • Avoid drinking or serving untreated/unfiltered water from streams, lakes, and other bodies of water. 
  • Adhere to local advisories to boil water, and avoid drinking or serving water of unknown quality or safety.
  • Do not swim or wade in pools or other recreational water until two weeks after diarrhea symptoms resolve.

Resource

About Cryptosporidiosis (CDC)