Highly frequent infections with human rhinovirus in healthy young children: a longitudinal cohort study.
ABSTRACT Human rhinoviruses (HRVs) are an important cause of respiratory tract infections.
We questioned whether the high prevalence rates of HRVs found in epidemiological studies is due to long-term individual continuity or a result of frequent infections with different HRV subtypes.
In a 6-month winter period 18 healthy controls, aged 0-7 years, were at least sampled every two weeks for HRV-PCR, irrespective of respiratory symptoms. All HRV positive samples were genotyped to determine HRV diversity.
In total 272 samples were collected. HRV was found in 101/272 (37%) samples. Genotyping revealed 27 different HRV subtypes. A median of 3.0 different HRV subtypes was found per child. Re-infections and continuity with identical HRV sequences were observed. The number of HRVs were higher in the youngest age group (p=0.01) and they had more different HRV subtypes (p=0.05) compared to oldest age group.
We found a high HRV exposition with a considerable diverse population of HRV subtypes in young children. These results have major implications for future research into the pathogenic role of HRV in respiratory diseases. Characterisation of subtypes will be necessary to discriminate between prolonged continuity and re-infections in patients with respiratory diseases.
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ABSTRACT: Carefully conducted, community-based, longitudinal studies are required to gain further understanding of the nature and timing of respiratory viruses causing infections in the population. However, such studies pose unique challenges for field specimen collection, including as we have observed the appearance of mould in some nasal swab specimens. We therefore investigated the impact of sample collection quality and the presence of visible mould in samples upon respiratory virus detection by real-time polymerase chain reaction (PCR) assays. Anterior nasal swab samples were collected from infants participating in an ongoing community-based, longitudinal, dynamic birth cohort study. The samples were first collected from each infant shortly after birth and weekly thereafter. They were then mailed to the laboratory where they were catalogued, stored at -80[degree sign]C and later screened by PCR for 17 respiratory viruses. The quality of specimen collection was assessed by screening for human deoxyribonucleic acid (DNA) using endogenous retrovirus 3 (ERV3). The impact of ERV3 load upon respiratory virus detection and the impact of visible mould observed in a subset of swabs reaching the laboratory upon both ERV3 loads and respiratory virus detection was determined. In total, 4933 nasal swabs were received in the laboratory. ERV3 load in nasal swabs was associated with respiratory virus detection. Reduced respiratory virus detection (odds ratio 0.35; 95% confidence interval 0.27-0.44) was observed in samples where the ERV3 could not be identified. Mould was associated with increased time of samples reaching the laboratory and reduced ERV3 loads and respiratory virus detection. Suboptimal sample collection and high levels of visible mould can impact negatively upon sample quality. Quality control measures, including monitoring human DNA loads using ERV3 as a marker for epithelial cell components in samples should be undertaken to optimize the validity of real-time PCR results for respiratory virus investigations in community-based studies.BMC Infectious Diseases 01/2014; 14(1):15. · 2.56 Impact Factor
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ABSTRACT: Infants, toddlers, and children of primary-school age without any special risk factors generally have three to ten febrile respiratory infections per year. Most such infections are of viral origin and self-limiting, but viral infection is often hard to distinguish from bacterial infection. The use of a multiplex polymerase chain reaction (PCR) to detect viruses in respiratory secretions is potentially beneficial, as it might help physicians avoid giving antibiotics unnecessarily.Deutsches Ärzteblatt International 09/2014; 111(38):639-45. · 3.61 Impact Factor
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ABSTRACT: Enteroviruses (EVs) often infect humans, presenting as endemic or epidemic infections. In this study, the diversity of infecting EVs was studied among 146 children and 137 adults in a small community in Cameroon. The participants provided 2,458 fecal samples during 1-year monthly collection; 10 or more samples were obtained from 55%. Partial 5′UTR-VP4 region could be sequenced in 393/547 PCR positive samples obtained from 119 children and 85 adults. EV-RNA was detected in at least one sample from 235 participants (83%) during the study period. A total of 121 different strains were identified, 66 infected only children, 29 only adults, and 26 infected both children and adults. There were children with up to five episodes with different strains, and adults with up to four such episodes. Infants aged <5 years were significantly more often EV infected compared to older participants. Infections with species EV-C constituted two third of all cases, and overall EV infections were more common during the rainy season. Species EV-B more often infected children than adults. Most strains were detected only for certain months of the year; however five strains were observed during the time spans of 5–10 months. Two strains were excreted up to eight months in three children and one adult. In 11 of the 128 families with paired samples the child and the adult were infected simultaneously by the same strain, indicating common source of infection. The study revealed a surprising complexity of EV ecosystem in a single community. J. Med. Virol. © 2014 Wiley Periodicals, Inc.Journal of Medical Virology 03/2014; · 2.22 Impact Factor