Year: 2013
Type: dissertation
Abstract: Background: Lower respiratory tract infections \n(LRTI) are a leading cause of morbidity and \nmortality in young children. A number of new \nviruses associated with LRTI in young children \nhave recently been discovered. These include \nHuman Bocavirus (HBoV), Human \nPolyomavirus strains WU (WUPyV) and KI \n(KIPyV) and Human Coronavirus strains NL63 \n(HCoV-NL63) and HKU-1 (HCoV-HKU-1). There \nis, however, limited data on the epidemiology \nof these newly discovered respiratory viruses \nin industrializing country settings, including \nSouth Africa. \nObjective: To determine the clinical \nepidemiology of HBoV, HCoV-NL63, HCoVHKU1, \nHCoV-OC43, HCoV strain 229E (HCoV- \n229E), WUPyV, KIPyV and human rhinovirus \n(HRV) in young children. \nMethods: Nasopharyngeal aspirates where \ntaken from children who were hospitalized at \nChris Hani Baragwanath Hospital between \nFebruary 2000 and January 2002 with severe \nLRTI. These children had been enrolled in a \ndouble-blind, randomized, placebo-controlled \ntrial of a 9-valent pneumococcal conjugate \nvaccine (PCV). Nucleic acid extraction was \nundertaken from archived nasopharyngeal \naspirate samples and the respiratory viruses \nidentified using real time duplex PCR. The \nstudy was limited to examining samples from \nHIV uninfected children with LRTI who were \nless than 24 months of age. \nResults: Overall, samples were available for \n895 of 1565 nasopharyngeal aspirates, from \nchildren hospitalized with LRTI, collected from \nFebruary 2000 to January 2002. A comparison \nbetween those LRTI episodes for which \nsamples were unavailable compared to those \nfor which samples were available indicated \nthat children in whom samples were \nunavailable were younger than children with \navailable samples (9.9±6.4 vs. 11.8±6.5 months; p<0.0001). In addition there was a \nhigher frequency of wheezing episodes in \nchildren for whom samples were unavailable \n(60.4 vs. 54.6%; p=0.022). \nThe overall prevalence of the viruses in \nchildren with any LRTI were 33.2% for HRV, \n21.2% for HBoV, 16.1% for WUPyV, 10.1% for \nHCoV-OC43, 7.0% for KIPyV, 3.2% for HCoVNL63, \n2.6% for HCoV-HKU-1, and 0.6% for \nHCoV-229E. There was a higher probability of \ndetecting a selected virus in LRTI episodes \namong PCV-compared to placebo-recipients \nfor HBoV (24.2% vs. 18.2%, respectively; \np=0.028) and HRV (36.7% vs. 29.5%, \nrespectively; p=0.023). Conversely, viruses \nidentified more frequently in LRTI episodes \namong children who received placebo \ncompared to PCV-recipients included WUPyV \n(20.2% vs. 12.1%, respectively; p=0.001), \nKIPyV (10% vs. 4.2%, respectively; p=0.001), \nHCoV-OC43 (14.1% vs. 6.2%, respectively; \np≤0.0001) and HCoV-HKU1 (4.5% vs. 0.1%, \nrespectively; p≤0.0001). \nOverall, the prevalence of the studied-viruses \nin the subgroup of children categorized as \nhaving bronchiolitis was 33.8% for HRV, 33.4% \nfor WUPyV, 22.3% for HBoV, 11.1% for HCoVOC43, \n5.3% for KIPyV, 2.3% for HCoV-NL63, \n1.9% for HCoV-HKU1 and 0.4% for HCoV-229E. \nViruses more commonly identified in placebocompared \nto PCV-recipients among children \nhospitalized with bronchiolitis included \nWUPyV (20.0% vs. 12.3%, respectively; \np=0.029), HCoV-OC43 (15.9% vs. 7.2%, \nrespectively; p=0.004) and HCoV-HKU1 (3.6% \nvs. 0.5%, respectively; p=0.015). \nThe prevalence of the newly studied viruses in \nthe subgroup of children categorized as having \nclinical pneumonia was 30.8% for HRV, 20.3% \nfor HBoV, 16.4% for WUPyV, 9.1% for HCoVOC43, \n8.6% for KIPyV, 4.1% for HCoV-NL63, \n3.2% for HCoV-HKU1 and 0.6% for HCoV-229E. \nViruses identified more frequently among \nplacebo- compared to PCV-recipients, in those \nwith clinical pneumonia, included WUPyV \n(20.4% vs. 11.9%, respectively; p=0.013),HCoV-HKU1 (5.3% vs. 0.9%, respectively; \np=0.008). Conversely, HCoV-OC43 was \nidentified more frequently in children with \nclinical pneumonia among PCV- (5.0%) \ncompared to placebo-recipients (2.7%, \np=0.004). \nThere were seasonal peaks, during autumnwinter \nmonths (April to June), in the detection \nof HRV, WUPyV, HCoV-OC43, HCov-NL63 and \nHCoV-HKU1, whereas KIPyV, HBoV and HCoV- \n229E were identified perennially. \nConclusion: Prevalence of respiratory viruses \nis high in industrializing countries and the \npresence of these viruses is frequently \nassociated with co-infections of more than \none etiological agent. In industrializing \ncountries such as in South Africa, the recently \nidentified respiratory viruses play a role in \ndevelopment of pneumonia. \nKIPyV (12.7% vs. 4.1%, respectively; p=0.001),
Author: Zelda Radebe
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: green
Funder: National Research Foundation
OpenAlex ID: W2139678077