A polymerase chain reaction-based epidemiologic investigation of the incidence of nonpolio enteroviral infections in febrile and afebrile infants 90 days and younger

Objective. Enteroviruses are important pathogens in infants, but their true contribution to febrile illness in infants less than or equal to 90 days old is unknown. The purpose of this study was to use the polymerase chain reaction (PCR) for diagnosis of enteroviral (EV) infection in febrile and afebrile infants less than or equal to 90 days of age to improve the understanding of the epidemiology of EV infection in this population. Methods. Patients included all unimmunized, febrile infants less than or equal to 90 days of age admitted to Primary Children's Medical Center (Salt Lake City, UT) for sepsis evaluation from December 1996 to December 1997. Blood, urine, cerebrospinal fluid, and throat swabs were tested for enteroviruses using a PCR assay (Roche Molecular Systems, Branchburg, NJ). Alternate PCR assays separated polio and nonpolio enteroviruses. Results of bacterial cultures, outcome, and hospital charges were obtained. Blood from afebrile, control infants less than or equal to 90 days old was tested for enteroviruses. Results. A total of 345 febrile infants were enrolled; 89 (25.8%) were positive for enterovirus. The incidence of EV infection ranged from 3.2% in January to 50% in August and October. Five EV-positive, febrile infants (5.6%) had concomitant urinary tract infections, and 1 (1.1%) had concomitant bacteremia. Infants with confirmed EV infection were significantly less likely to have bacterial infection than those who were EV-negative. All infants infected with an enterovirus recovered. Average length of stay was 3 days, average charges were nearly $4500. Eighty-six afebrile, control infants were enrolled; 6 (6.9%) were positive for enterovirus; 3 had received oral polio vaccine. Conclusions. Nonpolio EV infections commonly cause fever in infants less than or equal to 90 days of age. Rates of EV positivity are low in afebrile, unimmunized infants. The use of PCR to identify febrile infants with nonpolio EV infections may decrease length of hospital stay, unnecessary antibiotic administration, and charges.