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Sandra Gorsuch, MS
ISDH Field Epidemiologist, District 5
Lynae Granzow, MPH
ISDH Enteric Epidemiologist
On December 3, 2007, the Boone County Health Department (BCHD) notified the Indiana State Department of Health (ISDH) that a child who attended a local daycare was diagnosed with cryptosporidiosis. The daycare director stated that other children had symptoms of diarrhea. The BCHD initially instructed the daycare director to exclude all symptomatic attendees and staff.
The ISDH and the BCHD initiated a collaborative investigation to implement control measures and to prevent further transmission of the illness in the daycare. The daycare was an unlicensed facility. The index case, a daycare attendee, had onset of symptoms on November 15, 2007, and tested positive for Cryptosporidium and Giardia.
According to the Indiana Communicable Disease Reporting Rule (410 IAC 1-2.3), Section 61, when an outbreak of Cryptosporidium occurs in a daycare, all attendees and staff shall be required to submit stool specimens for laboratory analysis. All symptomatic attendees and staff shall be isolated from other attendees and staff and excluded, and admission of all new attendees shall be suspended until the outbreak has ceased.
To minimize exposure during the outbreak, the daycare attendees and staff were separated into three different groups:
· Those treated for at least three days with nitrazoxanide, or tested negative and without symptoms
· Those without symptoms
· Those with symptoms
To prevent disease transmission to other daycare facilities, health officials decided to keep symptomatic attendees in the daycare if the parents were unable to care for the children during daycare hours. The BCHD provided parents with fact sheets and a letter informing them of the outbreak. All daycare attendees and staff members were asked to provide stool specimens using the ISDH 4A parasitology container. A confirmed case was defined as any daycare symptomatic or asymptomatic attendee or staff member testing positive for Cryptosporidium or Giardia. A probable case was defined as any daycare attendee or staff member having compatible clinical symptoms in the absence of a known cause.
Fourteen attendees and one asymptomatic staff member tested positive for Cryptosporidium; five attendees (one asymptomatic) tested positive for Giardia, and one attendee was co-infected with both parasites (see Figure 1). The BCHD notified all Boone County school nurses about the outbreak, instructing them to take control measures to prevent spread of the illness in their schools. The majority of the daycare attendees and staff submitted stool specimens to the ISDH Laboratories for analysis (see Laboratory Results). Some attendees and staff were tested by their health care providers using private laboratories. New attendees were accepted into the daycare on January 14, 2007, one incubation period after the onset date of the last symptomatic case.
Seventy-five children attended the daycare at the time of the outbreak; the attack rate for Cryptosporidium was 19 percent and 7 percent for Giardia. Six children were removed from the daycare by their parents and only one was tested. Ages ranged from less than 1 year to 9 years of age (mean age = 3 years), and 89 percent of the cases were male. One staff member tested positive for Cryptosporidium, and two staff members who were released from employment by daycare management were not tested.
Figure 1. Epidemiologic Curve
*Dates of collection were used for the epidemiologic curve for the two asymptomatic cases (Giardia 12/21 and Cryptosporidium 12/27).
On December 7, 2007, a BCHD Communicable Disease Health Educator and a BCHD Environmental Health Specialist visited the daycare to inspect the premises. The daycare was divided into seven classrooms: a nursery, an infant room, and rooms for one-year-olds, two-year- olds, three-year-olds, four- and five-year-olds, and school-age children. The nursery was not utilized. Attendees were not separated by gender within the rooms.
Disposable gloves and covered trash containers for soiled diapers were located next to changing tables in the infant and one-year-old rooms. The hot water heater did not provide water measuring 120ºF, the temperature recommended for hand washing. The four toilets provided for the attendees were slow to flush or did not work properly. Sinks were clogged in the bathrooms for two-year-olds and school-age children. There were no paper towels in the bathroom for four- and five-year-olds. The soap dispenser was inaccessible in the bathroom for two-year-olds. The BCHD discovered several sinks with no running water and subsequently turned on the water. The BCHD requested that the daycare director correct the problems and noted they were resolved upon subsequent visits in December 2007 and January 2008. Hydrogen peroxide cleaning of the facility was recommended, since Cryptosporidium and Giardia have heightened resistance to chlorine.
Two representatives from the Family and Social Services Administration (FSSA) Region 4 Division of Family Resources and a BCHD Environmental Health Specialist visited the daycare on December 14, 2007. The FSSA Division of Family Resources regulates unlicensed daycares in Indiana. The FSSA mandated that the daycare director have the hot water heater fixed or purchase a new unit by December 17, 2007. The daycare director purchased a new hot water heater that weekend.
The daycare facility receives its water from the local municipal water system. According to a BCHD Environmental Health Specialist, a water main break had occurred approximate in time to the outbreak during new building construction near the daycare facility. The BCHD subsequently collected water specimens near the site and submitted them to the Indiana Department of Environmental Management (IDEM) for analysis (see Laboratory Results).
Seventy-six stool specimens were submitted to the ISDH Laboratories for analysis from December 10, 2007, through January 10, 2008. Six attendees tested positive for Cryptosporidium, four attendees tested positive for Giardia, and one staff member tested positive for Cryptosporidium. Eight attendees who were tested through private health care providers tested positive for Cryptosporidium; one was co-infected with Giardia.
Three water specimens collected on December 26, 2007, near the new construction site were submitted to IDEM for analysis. All three specimens were negative for coliforms and E. coli.
This investigation confirmed that an outbreak of Cryptosporidium and Giardia occurred at a local daycare from December 3, 2007, through December 27, 2007. The epidemiologic curve suggests person-to-person transmission of Cryptosporidium and Giardia within the daycare facility after initial infection of the index case. The index case’s exposure is unknown. Hygiene breaches at the facility likely contributed to the outbreak. There is no direct evidence that this outbreak was due to a water main break near the daycare. If the water main break was the original source of contamination, the water system was already repaired and cleared of contamination by the time the water samples were collected. However, no individuals from neighboring residences or businesses were identified with the illnesses.
Cryptosporidium and Giardia are one-celled parasites that live in the intestines of many animals. Cryptosporidium and Giardia parasites are protected by a cyst, an outer shell, which enables them to survive in the environment for long periods. Cryptosporidium cysts are highly resistant to iodine and chlorine and can survive for days in swimming pools with sufficient chlorine levels. The recommended disinfecting agents for Cryptosporidium are ammonia or hydrogen peroxide. Hydrogen peroxide is preferred, especially in a child-care setting, due to ammonia’s strong odor and production of hazardous gas when combined with chlorine.³ The mode of transmission for both parasites is fecal-oral, and people become infected by ingesting contaminated food or water, through contact with infected feces from humans or animals, or contact with contaminated environmental surfaces and objects.
Symptoms of cryptosporidiosis include watery diarrhea (the most common symptom), stomach cramps, slight fever, weight loss, and vomiting. Symptoms usually last 1 to 2 weeks, however, relapse can occur for up to 30 days. The incubation period is 2-10 days with an average of 7 days.³ Giardia symptoms include diarrhea, gas, greasy stools that tend to float, bloating, stomach cramps, and nausea.² Symptoms persist for 2 to 6 weeks, occasionally longer. The incubation period is 1-14 days with an average of 7 days.³ Persons infected with Cryptosporidium or Giardia can continue to shed in their stool for weeks after symptoms cease. Some asymptomatic infected individuals carry Cryptosporidium or Giardia in their intestines for weeks or months and can unknowingly infect others.
Cryptosporidium and Giardia, both highly contagious, are two of the most common causes of waterborne disease (found in both drinking and recreational water) in humans in the United States.³ Several community-wide outbreaks of Cryptosporidium and Giardia have been linked to drinking contaminated municipal water or contaminated recreational water. Potentially contaminated water includes water that has not been boiled, filtered, or disinfected with chemicals.³ Cryptosporidium and Giardia are common causes of diarrhea in children, particularly in child-care settings. For the most part, smaller outbreaks occur from contaminated food and person-to-person transmission in child-care settings.²
In general, Cryptosporidium and Giardia can be prevented by strictly adhering to the following guidelines:
The Indiana State Department of Health extends its appreciation to the Boone County Health Department for their quick response and professionalism. Their prompt and appropriate actions were instrumental in ending this outbreak.
1. Case Definitions for Infectious Conditions Under Public Health. 1997 and 1998. Centers for Disease Control and Prevention http://www.cdc.gov/ncphi/disss/nndss/casedef/case_definitions.htm
2. Communicable Disease Quick Facts, Indiana State Department of Health http://www.in.gov/isdh/healthinfo/quick_faqs.htm
3. CDC A-Z Index. Centers for Disease Control and Prevention http://www.cdc.gov/az/0.html