Heterotypic Infection and Spread of Rhinovirus A, B, and C among Childcare Attendees

Abstract

Background: Despite the frequency of human rhinovirus (HRV), data describing the molecular epidemiology of HRV in the community are limited. Childcare centers are optimal settings to characterize heterotypic HRV cocirculation.

Methods: HRV specimens were prospectively obtained from a cohort of childcare attendees at enrollment and weekly during respiratory illness. The 5' noncoding region sequences were used to determine HRV species (A, B, C) and genotypes.

Results: Among 225 children followed, sequence data were available for 92 HRV infections: HRV-A (n = 80; 59%) was most common, followed by HRV-C (n = 52, 39%), and HRV-B (n = 3, 2%). Forty-one genotypes were identified and cocirculation was common. Frequent spread between classrooms occurred with 2 HRV-A genotypes. Repeated detections within single illnesses were a combination of persistent (n = 7) and distinct (n = 7) genotypes. Prevalence of HRV among asymptomatic children was 41%. HRV-C was clinically similar to HRV-A and HRV-B.

Conclusions: HRV epidemiology in childcare consists of heterotypic cocirculation of genotypes with periodic spread within and among classrooms. Based on our finding of multiple genotypes evident during the course of single illnesses, the use of sequence-based HRV type determination is critical in longitudinal studies of HRV epidemiology and transmission.

Figure 1.

Flow chart of enrollment, sample collection, and testing. Abbreviation: HRV, human rhinovirus.

Figure 2.

Rhinovirus genotypes identified from November 2008 through June 2009. Frequency of human rhinovirus (HRV) genotypes is labeled over time. * Species identified, no genotype identified within 95% homology to the 5′ noncoding region.

Figure 3.

Rhinovirus outbreak from 12 January to 24 February 2009. A, Epidemiologic curve of human rhinovirus (HRV) detection. Day 0 is January 12. Letter in box indicates child’s room (see B) and color indicates genotype. Repeat detections of a genotype in a single child were observed twice in this period, marked with asterisk (*). B, Location of genotypes is indicated on the classroom map, with each classroom labeled A through J. Each HRV detection (small circle or diamond) is labeled by day of sample (number) and genotype (color). The first occurrences of common genotypes (Au6, A12, C2) are marked with a diamond. Repeat detections of a genotype in a single child were observed twice in this period, marked with asterisk (*). Black boxes indicate rooms not used for childcare.