Pediatric Annals

Risk of Enteric Infection Associated With Child Day Care

Ardythe L Morrow, PhD, MSc; Irene T Townsend, RN; Larry K Pickering, MD

Abstract

In recent years, a demographic trend in the United States has been to group unrelated children together for day care.1 Placing children together in group care increases the opportunity for transmission of infectious diseases. Enteric pathogens that are transmitted by the fecal-oral route are particularly likely to be spread in groups of infants and toddlers who are not yet toilet trained.2-7 Approximately one half of the diarrheal illnesses in children younger than 3 years of age who attend day care can be attributed to the acquisition of the infection at a day-care facility.2,4,7

When an infant or toddler presents to his or her pediatrician because of diarrhea, the possibility that the illness was acquired in day care must be considered. In one study, 20% of visits by young children to the physician's office for diarrhea were attributable to infection acquired in day-care centers. Thus, in addition to managing and treating the child with diarrhea, the pediatrician should determine whether the child is in day care, recognize the potential for transmission of the infecting agent, and be aware of how to prevent and control the spread of the infection to other children. This article summarizes the variety of viral, bacterial, and parasitic enteropathogens that are known to be transmitted in day care; the risk factors for acquiring diarrheal illness at day-care facilities; and the current recommendations for preventing and controlling these infections.

ENTEROPATHOGENS

Enteropathogens that have been associated with outbreaks of diarrhea in day-care centers are listed in Table 1. Rotavirus, Shigella, and Giardia iambita have been the most frequently reported enteropathogens associated with outbreaks of diarrhea; other enteropathogens reported include Compylobacter jehuni, CIostridium difficile, strains of Escherichia coli, calicivirus, enteric adenovirus (types 40 and 41), and Cryptosporidium.8'12 Among outbreaks reported, the attack rates of symptomatic infection have varied widely. Attack rates for G lamblia and Campylobacter have ranged from 17% to 54%, and the reported attack rates for Shigella and Cryptosporidium have ranged from 33% to 73%.9 Salmonella is rarely identified in day care. Person-to-person spread is the major route of transmission of enteric infection in day care, while foodbome or waterborne infection is uncommon.8

Table

PREVENTION AND CONTROL OF DIARRHEA IN DAY CARE

Prevention of diarrheal disease in child care is difficult to achieve for several reasons. The typical behavior of young, diapered children facilitates fecaloral transmission. Further, the inoculum dose required for infection is as low as 10 to 100 organisms for some enteric pathogens, such as G lamblia and Shigella. Despite these limitations, diarrheal illness in day-care settings can be reduced substantially.

In mid- 1991, national standards for infectious disease control in the child-care setting are scheduled for distribution as part of the National Health and Safety Standards for out-of-home child care, which have been developed by the collaboration of experts from the American Public Health Association and the American Academy of Pediatrics.24 Some of the recommendations found in the national standards for the prevention and control of enteric infection in child care are summarized in Table 3. Written policies describing the measures to prevent and to control infections should be adopted and available at every child-care facility. A policy of frequent handwashing by staff and children is essential to reduce transmission of enteropathogens. Child-care providers who change diapers should be provided a designated changing area that has a surface which can be sanitized after each change. If the surface is covered with paper, the paper should be contained and disposed of appropriately. In addition, policies that require clothing to be worn over diapers and the use of paper rather than cloth diapers should be adopted to…

In recent years, a demographic trend in the United States has been to group unrelated children together for day care.1 Placing children together in group care increases the opportunity for transmission of infectious diseases. Enteric pathogens that are transmitted by the fecal-oral route are particularly likely to be spread in groups of infants and toddlers who are not yet toilet trained.2-7 Approximately one half of the diarrheal illnesses in children younger than 3 years of age who attend day care can be attributed to the acquisition of the infection at a day-care facility.2,4,7

When an infant or toddler presents to his or her pediatrician because of diarrhea, the possibility that the illness was acquired in day care must be considered. In one study, 20% of visits by young children to the physician's office for diarrhea were attributable to infection acquired in day-care centers. Thus, in addition to managing and treating the child with diarrhea, the pediatrician should determine whether the child is in day care, recognize the potential for transmission of the infecting agent, and be aware of how to prevent and control the spread of the infection to other children. This article summarizes the variety of viral, bacterial, and parasitic enteropathogens that are known to be transmitted in day care; the risk factors for acquiring diarrheal illness at day-care facilities; and the current recommendations for preventing and controlling these infections.

ENTEROPATHOGENS

Enteropathogens that have been associated with outbreaks of diarrhea in day-care centers are listed in Table 1. Rotavirus, Shigella, and Giardia iambita have been the most frequently reported enteropathogens associated with outbreaks of diarrhea; other enteropathogens reported include Compylobacter jehuni, CIostridium difficile, strains of Escherichia coli, calicivirus, enteric adenovirus (types 40 and 41), and Cryptosporidium.8'12 Among outbreaks reported, the attack rates of symptomatic infection have varied widely. Attack rates for G lamblia and Campylobacter have ranged from 17% to 54%, and the reported attack rates for Shigella and Cryptosporidium have ranged from 33% to 73%.9 Salmonella is rarely identified in day care. Person-to-person spread is the major route of transmission of enteric infection in day care, while foodbome or waterborne infection is uncommon.8

Table

TABLE 1Enteropathogens Associated With Outbreaks of Diarrhea in Child-Care Settings

TABLE 1

Enteropathogens Associated With Outbreaks of Diarrhea in Child-Care Settings

Identification of enteropathogens causing diarrhea in day care has depended on the availability of specialized diagnostic techniques as well as the interest of investigators in areas where outbreaks have occurred. As laboratory techniques continue to develop, it is reasonable to expect that enteropathogens other than those listed in Table 1 also will be found to occur frequently in the day-care setting.

SEVERITY OF ILLNESS

Most diarrheal illness in day care is self-limited and of mild to moderate severity. The mean duration of 572 diarrheal illnesses detected in children in 12 day-care centers studied over a 15-month period in Houston, Texas, was 3.4 days.3 By contrast, in a few instances, the diarrheal illness or sequelae are severe or prolonged, require hospitalization, and result in death. There have been two reported outbreaks of bloody diarrhea in day-care centers caused by E coli 0157:H7 infection. In one center, 36 of 107 (34%) children had bloody diarrhea13 caused by E coü 0157:H7. In the second center, the E coli 0157:H7 strain was identified in stools from 23 of 80 (29%) children.14 Three children at each center developed hemolytic uremie syndrome.

In two outbreaks of enteropathogenic E coli (EPEC) 0111:K58 infection, 15 of 16 (94%) infants had diarrhea at one center,15 and 14 of 25 (56%) children had diarrhea for a mean of 12 days at the second center.16 A total of seven children in the two EPEC outbreaks required hospitalization. During another outbreak with a sorbitol negative, enteroadherent factor positive E coli Ol 14:NM, 16of24 (67%) infants developed diarrhea and five were hospitalized for a mean of 4 weeks.17 This latter outbreak subsequently spread to four hospital contacts and a member of one patient's household.

Other morbidity has been attributed to outbreaks of enteropathogens in day-care centers. Besides an increase in hospitalisations, transmission of infection to the community has been traced to outbreaks of Shigella infection in day-care centers.18 Day-care centers also have been associated with outbreaks of diarrhea caused by antibiotic-resistant strains of Shigella.19 In addition, excess visits to the pediatrician have been documented for rotavirus-associated diarrhea acquired by children attending day-care facilities.2 Thus, although the majority of diarrheal illnesses acquired in day-care centers are of mild to moderate severity, these illnesses have the potential to be serious and prolonged, and contribute to illness in the community at large.

INCIDENCE OF DIARRHEA IN DAY-CARE CENTERS

Prospective studies of diarrheal disease in iniants and toddlers attending day-care centers have been conducted in Maricopa County, Arizona,4 and in Houston, Texas.11,20 In both studies, diarrheal disease occurred throughout all months of the year. An outbreak of diarrhea in a group of children was defined as three or more cases during a single week. Outbreaks developed an average of three to four times per year.4,11

In Arizona, the incidence of diarrheal illnesses in 655 children who attended 22 study centers was 1.02 cases per child per year.4 This rate was lower than in the Houston study, which used more comprehensive surveillance procedures. Children in the 13 study centers in Houston had an incidence of 2.6 diarrheal illnesses per child per year.11'20 The incidence rates for infection varied considerably by enteropathogen as well as from center to center and from year to year. For rotavirus and Giardia, the average annual infection rates were 0.611'20 and I12 infections per child per year, respectively.

ASYMPTOMATIC INFECTION

Testing stool specimens from asymptomatic children has revealed that many enteric infections among children in day-care centers are asymptomatic. Prospective studies of children in day-care centers have established that 40% to 60% of the infections with rotavirus9'11'20 and 75% to 80%12 of infections with G lamblia are asymptomatic. Asymptomatic infections with Shigeüa, Cryptosporidium, Campylobacter, calicivirus, and enteric adenovirus among children in day-care centers also have been reported.8'10 Children who become symptomatic may excrete enteropathogens asymptomatically for several days before and after symptoms, especially if infected with rotavirus or Giordia.

TYPES OF CHILD-CARE FACILITIES AND RISK OF DIARRHEA

Classification of child-care facilities is generally based on location (residential or non- residential) and the total enrollment at the facility.2 National surveys indicate that the majority of young children receive care in residential day-care homes.1,2 Day-care homes are classified into two main types, "family" and "group" homes. Family homes provide care for fewer than six children at the residence of the caregiver. Group homes provide care for up to 12 children at a residence, and employ more than one caregiver.

Child-care centers typically are nonresidential facilities that provide care for 12 to several hundred children. Children are placed in groups based on their age and developmental level. Centers provide care on varying schedules (part-day, nail-day, part-week, fullweek, part -year or year-round), are regulated by the state, and must be registered. The quality of child care and the education of care providers at both centers and homes varies widely.

Three well-conducted epidemiologie studies have compared the risk of diarrheal illness among children in day-care centers, day-care homes, and home care2'7 (Table 2). In Maricopa County, Arizona, Bartlett et al concurrently followed infants and toddlers attending six day-care centers, 30 registered or sponsored day-care homes, and 102 households not using out-of-home child care.4"6 Over a 10-week period, the incidence of diarrhea was found to be significantly higher (slightly more than twofold) among children attending day-care centers than among children who received care at home. The incidence of diarrhea! illness among children attending day-care homes was only slightly higher and not significantly different than among children who received care in their own home.

Table

TABLE 2Estimated Relative Risks of Diarrheal Disease for Children Under 3 Years of Age by Type of Child-Care Setting

TABLE 2

Estimated Relative Risks of Diarrheal Disease for Children Under 3 Years of Age by Type of Child-Care Setting

Alexander et al7 analyzed interview data regarding 4845 children aged O to 5 years. The data were collected as part of the 1981 National Health Interview Survey and the 1981 Child Health Supplement. Parents were asked to recall any acute gastrointestinal tract illness in their child that occurred within the 2 weeks prior to the interview and resulted in doctor visits, hospitalizations, restricted activity days, or bed disability days. Seventythree percent of the children received care at home, 18% received care in someone else's home, and only 9% received care in a center or school. Among children under 3 years of age, attendance at a center for more than 10 hours per week was associated with a more than threefold increased risk of acute gastrointestinal tract illness compared to children in care at home. Care in someone else's home was not a significant risk factor for acute gastrointestinal tract illness compared to care in the child's own home.

A third study by Rêves et al2 compared 339 children under 3 years of age who presented to an ambulatory pediatrie clinic with diarrheal illness to 363 age-matched and season-matched well control children. The risk of clinic visits for acute diarrhea was significantly greater for children attending daycare centers (more than twofold increase in risk) and day-care homes (a twofold increase in risk) when compared with children cared for at home.

The results of these three studies support an increased risk of acute diarrheal disease associated with day-care center attendance, but risk with daycare home attendance is less clear. The third study2 provides evidence that there may be increased risk of diarrhea among children enrolled in day-care homes compared with care in the child's own home.

OTHER FACTORS AFFECTING RISK OF ENTERIC INFECTION IN DAY CARE

Age of Child Enrolled

Risk of diarrheal disease is affected by the age of the child enrolled in the day-care center. Among children in Houston day-care centers, the incidence of diarrhea was found to decline significantly with age. The incidence of diarrhea was highest among infants at 3.6 cases per child per year, declining to 1.3 cases per child per year among children older than 18 months,3 Several studies3,7 have indicated that the excess risk of diarrhea among day-care center attendees is found principally in children under 2 or 3 years of age.

Recent Enrollment

In a cohort study of 442 children under 2 years of age followed over a 15-month period, the annualized incidence of diarrhea in the first 4 weeks following enrollment in a new day-care center was 4.4 cases per child per year, significantly higher than the incidence of 2.7 cases of diarrhea per child per year found among children during subsequent weeks after enrollment.3 The finding of increased risk during the first month after enrollment in a new day-care arrangement was confirmed by a case-control study of diarrhea and day care use.2

Hygienic Practices and Environmental Contamination

Environmental studies in day-care centers have shown that there is frequent contamination with fecal coliform bacilli of hands of children and care providers and of environmental surfaces, which indicate contamination of these surfaces by human excreta. The occurrence of diarrhea in day-care centers has been found to be associated with increased contamination of children's and caregiver's hands.21,22

The handwashing practices of child-care providers may be the single most important measure in the prevention of transmission of enteric infection. A study conducted by Black et al23 found that instituting a handwashing program for caregivers plus continuous monitoring of handwashing practices was associated with a 50% decrease in the incidence of diarrhea in two day-care centers. One-time training of personnel about the importance of handwashing without subsequent monitoring has not been found to decrease rates of diarrheal illness.6

There are factors in addition to handwashing that are important to hygiene in day-care facilities. Two separate studies in Houston day-care centers have found that day-care center rooms in which children wore clothes over diapers had less fecal coliform contamination of hands and environmental surfaces than rooms in which children did not wear overclothes.21'22 In addition, the second study found that use of paper diapers by children in day-care centers was associated with less fecal contamination of the day-care environment than when cloth diapers were used by children.22

Table

TABLE 3Recommended Measures to Prevent and Control Enteric Infection in the Child-Care Setting

TABLE 3

Recommended Measures to Prevent and Control Enteric Infection in the Child-Care Setting

PREVENTION AND CONTROL OF DIARRHEA IN DAY CARE

Prevention of diarrheal disease in child care is difficult to achieve for several reasons. The typical behavior of young, diapered children facilitates fecaloral transmission. Further, the inoculum dose required for infection is as low as 10 to 100 organisms for some enteric pathogens, such as G lamblia and Shigella. Despite these limitations, diarrheal illness in day-care settings can be reduced substantially.

In mid- 1991, national standards for infectious disease control in the child-care setting are scheduled for distribution as part of the National Health and Safety Standards for out-of-home child care, which have been developed by the collaboration of experts from the American Public Health Association and the American Academy of Pediatrics.24 Some of the recommendations found in the national standards for the prevention and control of enteric infection in child care are summarized in Table 3. Written policies describing the measures to prevent and to control infections should be adopted and available at every child-care facility. A policy of frequent handwashing by staff and children is essential to reduce transmission of enteropathogens. Child-care providers who change diapers should be provided a designated changing area that has a surface which can be sanitized after each change. If the surface is covered with paper, the paper should be contained and disposed of appropriately. In addition, policies that require clothing to be worn over diapers and the use of paper rather than cloth diapers should be adopted to decrease fecal contamination of the day-care environment.21,22,24

Toys that are mouthed and other frequently handled surfaces in the environment should be cleaned frequently. Children of different developmental levels and ages should be cared for in separate groups. A child who develops diarrhea, fever, or vomiting that might be caused by an infection should be removed from contact with well children,24 although isolation of symptomatic children from well children may be difficult to achieve in child care, especially when a large proportion of the exposed children develop mild symptomatic illness.4,8,9'11 Ideally, a knowledgable medical advisor should be readily available for consultation.

SUMMARY

Pediatricians may advise parents that diarrhea is a frequent occurrence among infants and toddlers in day care and that diarrhea is usually mild and self-limited. A child newly enrolled in a day-care facility is at a particularly high risk for developing a diarrheal illness within the first month after enrollment, but the risk has been found to decrease as children remain in the same setting.3

Children who have diarrhea, fever, or vomiting of infectious origin should be isolated from well children. Infants and toddlers may return to the day-care environment when their diarrhea subsides and they are feeling well. Transmission of enteric infection from the child attending day-care center to other members of the family is possible; therefore, family members should also routinely practice good hygiene. Child-care providers should enforce written guidelines that establish hygienic practices and outline the management of ill children. Parents should be encouraged to read these policies and observe practices within the child-care setting before deciding to enroll their child in any care setting.

The National Standards for out-of-home child care scheduled for release in 1991 will be important reading and a comprehensive reference for pediatricians who choose to be a child health consultant to one or more day-care facilities.24

REFERENCES

1. Aronson SS. Political and social aspects of child day care. Seminars in Pediatric Infectious Distases. 1990;l: 195-203.

2. Reves RR, Morrow AL, Barden AV, Picketing LK. Case commi study of risk factors for acute diarrhea among children visiting a health maintenance organization clinic. Presented at the 28th Interscience Conference on Antimicrobial Agents and Chemotherapy; October 23-26. 1988; Los Angeles, Calif.

3. Staat MA, Morrow AL, Reves RR, Bartlett AV, Picketing LK. Diarrhea in children newly enrolled in day care centers in Houston. Pediatr Infect. Dis J. 1991;10:282-286.

4. Banleil AV, Moore M, Gary GW, Starko KM, Erben JJ, Meredith BA. Diarrheal illness among infants and toddlers in day tare centers. J epidemiology and pathogens. J Pediatr. 1985:107:495-502.

5. Bartlett AV. Moore M, Gary GW, Starko KM. Erben JJ, Meredith BA. Dianheal illness among iniants and toddlers in day care centers, IL comparison with day care homes and households. J Pediatr. 1985;I07:503-509.

6. Bartlett, AV. Jarvis BA. Ross V. et aL Diarrheal illness among infants and toddlers in day care centers: effetti of active surveillance and staff training without subsequent monitoring. AmJ Epidemiol. 1988; 127:808-8 17.

7. Alexander CS, Zinieleta EM, Mackenzie EJ, Vernon A, Markowitz RK. Acute gastrointestinal illness and child care arrangements. Am J Epidemiol. 1990:131:124-131.

8. Pickering LK. Bacterial and parasitic enteropathogens in day care. Smuri Pedina Infect Dis. 1990;1:263-269.

9. O'Ryan, Maison DO. Viral gastroenteritis pathogens in the day care center setting. Seminan m fiatarne infectious Diseases. 1990; 1:252 -262.

10. Van R, O'Ryan M, Matson El et al. Outbreaks of human adcnovirus types 40 and 41 in Houston day care centers. Presented at the Society fot Pediatrie Research; April 30, 1991; New Orleans, La.

11. Bartlett AV. Reves RR, Pickering LK. Roiawras in infant-toddler Jay care centers: epidemiology relevant to disease control strategics. J Pediatrn. 1988;11 3:435-441.

12. Rauch AM, Van R, Bartlett AV, Pickering LK. Longitudinal study of Giordia lamblia infection in a day care center population. Pediatr Infect. Dis J. 1990;9:186-189.

13. Spika JS. Parsons JE, Nordenberg D, Wells JG, Ounn RA, Blake PA. Hemolytic uremie syndrome and diarrhea associated with Escherichia coli 0157:H7 in a day care center, J Pediatr. 1986; 109: 287-291.

14. Belongia EA, MacDonald KL. Blaser MJ, Soler JT. Ammend DA, Osterholm MT. Outbreak of Eichericrua coii 015?;H7 in day care centers: patterns of transmission and control methods. Presented at the 28th Interscience Conference on Antimicrobial Agents and Chemotherapy; September 18, 1989; New Orleans, La.

15. Los Angeles County Department of Health Services. Day care center outbreak of severe gastroenteritis associated with enteropathogenic Escherichia coli. Public Health Letter. 1980;2:34-35.

16. Paulozzi LJ, Johnson KE, Kamahele LM, Clausen CR, Riley LW, Helgerson SD. Diarrhea associated with adherent enteropathogenic £ coli in an infant and toddler center, Seattle, Washington. Pediatrics. 1986;77:296-300.

17. Bower JR, Congeni BL, Cleary TG, el al. Escherichia cali 0114: non-motile as a pathogen in an outbreak of severe diarrhea associated with a day cire. J Infect Dis. 1989;160:243-247.

16. Rosenberg ML, Weissman JB, Gangarosa EJ, Relier LB, Beasley RP Shigellosis in the United States: In year review of nationwide surveillance. 1964-1974. Am J Epidemiol. 1976; 1 04:543- 551.

19. Tauxe RV, Johnson KE, Boase JC. Helgerson SC, Blake PA. Control of day care shigellosis: a trial of convalescent day care in isolation. Am J Public Health 1986:76:627-630.

20. O'Ryan ML, Matson DO, Estes MK, Bartlett AV, Pickering LK. Molecular epidemiology of rotovirus in children attending day care centers (DCC) in Houston. J Infect Dis. 1990; 162:810-816.

21. Van R, Morrow AL, Reves RR, Pickering LK. Environmental contamination in child day care centers. Am J Epidemiol 1991;133:460-470.

22. Van R. Wun C.C. Morrow AL, Pickering LK. The efiect of diaper type and overclothing on fecal contamination in day care centers. JAMA. 1991:267:1840-1844

23. Black RE, Dykes AC, Anderson KE, et al. Handwashing to prevent diarrhea in day care centers. Am J Epidemiol. 1981;11):445-451.

24. Giebink GS. National standards for infection control in out-of-home child care. Saminars in Pediatric Infectious Diseases. 1990;1:184-194.

TABLE 1

Enteropathogens Associated With Outbreaks of Diarrhea in Child-Care Settings

TABLE 2

Estimated Relative Risks of Diarrheal Disease for Children Under 3 Years of Age by Type of Child-Care Setting

TABLE 3

Recommended Measures to Prevent and Control Enteric Infection in the Child-Care Setting

10.3928/0090-4481-19910801-08

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