NORFOLK, Va. Respiratory tract and enteric pathogens are the most frequently encountered infectious agents in the child-care environment, and incidence increases as children return to school and out-of-home child care settings.
The most common acute illnesses in the United States are respiratory tract infections (RTIs), which include colds, sinusitis, pharyngitis, pneumonia and otitis media. These types of illnesses occur more frequently in children cared for out of the home and especially in those younger than 2 years, according to Larry K. Pickering, MD, director of the Center for Pediatric Research at Childrens Hospital of The Kings Daughters, Norfolk, Va.
The organisms that cause RTIs include adenovirus, respiratory syncytial virus, parainfluenza viruses, rhinovirus, coronavirus, influenza viruses, enteroviruses and Streptococcus pneumoniae. These pathogens are transmitted primarily by direct inoculation of infectious particles from hand to nasal, pharyngeal or conjunctival mucosa.
Prevention of RTIs caused by these ubiquitous organisms is difficult because they are highly infectious and may be shed before or after the symptomatic period. They may also possibly survive for a significant time outside the host. However, the most effective means of preventing the spread of respiratory tract pathogens is hand washing.
"Having sinks in the room with the children is critical to prevention of disease spread. Its a good opportunity to teach children about hand washing. You can teach them that its important to wash their hands and when to wash their hands if the sinks are available. It can be utilized as an educational opportunity," said Pickering, who is also professor of pediatrics at Eastern Virginia Medical School.
Infants can be infected through caretakers or other infants, but toddlers are effective transmitters of these pathogens because of their ambulatory status, age-specific personal hygiene and behaviors that involve exchange of secretions, Pickering explained. Daily cleaning of toys and other materials handled by children is recommended because shared objects may also play a part in transmission.
Bordetella pertussis can also be transmitted in a child-care setting, but occurs much less frequently. The most common mode of transmission is from an adult with waning immunity to an unimmunized infant younger than 6 months who may not have completed the primary immunization series.
Pathogens causing invasive bacterial infections, including S. pneumoniae, Neisseria meningitidis, Haemophilus influenzae type b (Hib) and varicella are also transmitted through the respiratory route.
S. pneumoniae is a major cause of pneumonia, meningitis, otitis media and bacteremia in infants and children. According to Pickering, child care attendance has been shown to be a significant risk factor for nasopharyngeal colonization and invasive disease caused by S. pneumoniae.
N. meningitidis is a major cause of meningitis and septicemia. Although an increased risk for primary meningococcal disease in children attending child-care facilities has not been definitely established, several studies have suggested an increased risk for secondary disease associated with child-care attendance.
Since the introduction of Hib conjugate vaccines, a significant decrease in disease incidence has been reported. Prior to the vaccine, several studies indicated an increased risk for primary disease caused by Hib in children in out-of-home day care settings.
Varicella outbreaks have also been documented in child-care settings. Prevalence of varicella in children who attended child care facilities was higher than in children in the general population, according to a 1995 survey. The survey also indicated that varicella in children attending day care centers also occurred at a younger age and disease prevalence was higher in larger centers.
The Centers for Disease Control and Prevention is currently conducting a varicella surveillance project to document changes in the epidemiology of varicella, secondary to the introduction of a varicella vaccine licensed in March 1995. The project for surveillance of varicella in the United States was established at the end of 1994. It will run for five years.
Acute infectious diarrhea is the second most common illness involving children attending out-of-home care facilities. Children in day care are three times more likely to develop diarrheal illness compared with children cared for at home, and children just entering day care are also more susceptible than "age-matched veterans" of child care, Pickering said.
Organisms responsible for diarrhea in child care settings include rotavirus, astrovirus, calicivirus, enteric adenovirus, Giardia lamblia, Cryptosporidium, Shigella, some types of Escherichia coli, Salmonella, Campylobacter,and Clostridium difficile..
Most episodes of diarrhea in the child care setting result from person-to-person transmission; foodborne outbreaks are rare, Pickering said.
Several factors contribute to increased incidence of diarrheal disease in child care environments: high infectivity of many enteric pathogens, grouping of large numbers of susceptible individuals, asymptomatic infection and environmental fecal contamination. However, the most important factor, Pickering noted, appears to be the presence of children in diapers.
Outbreaks caused by Hepatitis A virus (HAV) infection in children attending out-of-home care facilities are well documented. Children younger than 6 years may be asymptomatic or present with nonspecific symptoms, allowing for silent infection of other children. Parents of infected children often become ill first, followed by child care workers.
The most important risk factor for adult HAV infection is contact with children wearing diapers, Pickering said.
For more information:
- Churchill RB, Pickering LK. Infection control challenges in child-care centers. Infect Dis Clin North Am 1997;11:347-365.
- AAP. Children in out-of-home child care.. In: Peter G, ed. 1997 Red Book: Report of the Committee on Infectious Diseases 24th ed. Elk Grove Village, IL: American Academy of Pediatrics;1997:80.
- AAP. School health. In: Peter G, ed. 1997 Red Book: Report of the Committee on Infectious Diseases 24th ed. Elk Grove Village, IL: American Academy of Pediatrics;1997:93.
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