Incidence of congenital and postnatal cytomegalovirus infection during the first year of life in Mexican preterm infants.

Cytomegalovirus infection occurs commonly during infancy. Postnatal infection in term infants is usually asymptomatic; however, infection in preterm infants can be associated with clinical manifestations during the neonatal period. Nevertheless, few studies to assess the frequency of cytomegalovirus infection in preterm infants have been performed outside of high-income countries. We analyzed the incidence of congenital and postnatal cytomegalovirus infection in a cohort of preterm infants. Cytomegalovirus infection was detected during the neonatal period in four of 178 infants; in three of them, the virus was detected during the first 3 weeks of life and, therefore, congenital infection was confirmed (1.7% incidence). Postnatal infection was detected in 44 (36.4%) of 121 infants who were assessed after discharge from the neonatal intensive care unit. Cytomegalovirus infection was significantly associated with the duration of breastfeeding. In addition, we characterized cytomegalovirus strains detected in infants together with sequences available at GenBank, based on sequences of the UL18 gene. Cytomegalovirus UL18-sequences clustered in five distinct clades (A-E), and sequences obtained from infants in our study were distributed in four of the five clades; 44.4% of these sequences were included in clade E. Breastfeeding duration was shorter on average (5.6 months) in infants with sequences in clade E compared to infants with sequences in the other three clades (8.2 months; p = .07). In conclusion, we provide information regarding the high incidence of cytomegalovirus infection in preterm infants. Further studies are warranted to assess if cytomegalovirus strain characteristics are associated with the risk of infection acquisition during infancy.

Severe Respiratory Syncytial Virus Infection in Hospitalized Children.

BACKGROUND: Lower respiratory tract infections (LRTI) are one of the most common causes of death worldwide. Respiratory syncytial virus (RSV) is a leading cause of LRTI in children. Despite of its epidemiological importance, there is limited information regarding the impact of this virus in Latin America. AIMS OF THE STUDY: We carried out a prospective study to establish the frequency and characteristics of RSV infections in hospitalized Mexican children. METHODS: 1,252 children hospitalized between November, 2012 and December, 2015 because of LRTI were included in the study. A respiratory sample was obtained for RSV detection by RT-PCR and information regarding clinical presentation, hospital course, and outcome was recorded. RESULTS: RSV was detected in 43.7% of children admitted with LRTI, in 43.3% of those admitted to the intensive care unit (ICU), and in 36.4% of those who died. Infants with RSV infection were younger, were diagnosed with bronchiolitis more frequently, and were less likely to have underlying disorders than those with RSV-negative LRTI. Among RSV-positive infants, admission to the ICU was associated with the presence of underlying conditions, pneumonia diagnosis, and young age. Four (0.73%) of the 547 infants with RSV infection died; death was more common in those with underlying disorders than previously healthy infants (3.8 vs. 0.2%, respectively; p = 0.02). CONCLUSION: RSV contributes to a large proportion of LRTI hospital admissions. Most children admitted with RSV infection do not have underlying conditions. However, severe infection requiring ICU admission and death are more common in those with underlying disorders.