Prevalence of respiratory viruses in wheezing children not older than 24 months of age.

INTRODUCTION: Wheezing in children not older than 24 months of age is a frequent event, and viruses are usually the causative agents. The aim of the study was to estimate the prevalence of respiratory viruses in wheezing children who were not older than 24 months of age and who had no history of asthma. METHODS: Fifty-five Mexican children were included in an analytical cross-sectional study. Nasal secretions were obtained by using sterile rayon-tipped applicators to identify the virus by polymerase chain reaction or reverse transcription-polymerase chain reaction: adenovirus, bocavirus, human rhinovirus, influenza virus type A, human metapneumovirus, parainfluenza, rhinovirus, and respiratory syncytial virus. The prevalence of viral etiology was estimated by dividing the frequency of the identified virus by the number of participants. Ninety-five percent confidence intervals for proportions were calculated. RESULTS: Most of the patients were male (35/55, 63.6%). The average time of evolution of wheezing episode was 3 days. The third part of enrolled population were receiving antibiotics. Respiratory viruses were detected in 33 (60%; 95% CI: 46.8-71.9%) out of 55 cases, and viral coinfection was detected in five cases (9.1%; 95% CI: 3.5-19.9%). Human metapneumovirus was the most frequently identified virus (23.6%), followed by bocavirus (14.5%), respiratory syncytial virus and rhinovirus (12.7% each), and to a lesser extent influenza virus type A and parainfluenza. Rhinovirus was the predominant virus in outpatient children (28.6%). In the inpatient emergency room and inhalotherapy room, human metapneumovirus predominated (41.2 and 16.1%, respectively). CONCLUSION: bocavirus and human metapneumovirus were the most frequently identified viruses in Mexican children who were < 2 years of age, suffered from wheezing, and had no history of asthma.

4EBP1 Is Dephosphorylated by Respiratory Syncytial Virus Infection.

Respiratory syncytial virus (RSV) requires protein biosynthesis machinery to generate progeny. There is evidence that RSV might alter some translation components since stress granules are formed in their host cells. Consistent with these observations, we found that RSV induces dephosphorylation of 4EBP1 (eIF4E-binding protein), an important cellular translation factor. Our results show no correlation between the 4EBP1 dephosphorylation time and the decrease in the global rate of protein synthesis. Interestingly, treatment with rapamycin stimulates virus generation. The results suggest that RSV is a virus that still contains unknown mechanisms involved in the translation of their mRNAs through the alteration or modification of some translation factors, such as 4EBP1, possibly to favor its replicative cycle.

Clinical characteristics and genetic variability of human rhinovirus in Mexico.

Human rhinovirus (HRV) is a leading cause of acute respiratory infection (ARI) in young children and infants worldwide and has a high impact on morbidity and mortality in this population. Initially, HRV was classified into two species: HRV-A and HRV-B. Recently, a species called HRV-C and possibly another species, HRV-D, were identified. In Mexico, there is little information about the role of HRV as a cause of ARI, and the presence and importance of species such as HRV-C are not known. The aim of this study was to determine the clinical characteristics and genetic variability of HRV in Mexican children. Genetic characterization was carried out by phylogenetic analysis of the 5'-nontranslated region (5'-NTR) of the HRV genome. The results show that the newly identified HRV-C is circulating in Mexican children more frequently than HRV-B but not as frequently as HRV-A, which was the most frequent species. Most of the cases of the three species of HRV were in children under 2 years of age, and all species were associated with very mild and moderate ARI.