The relationship of meteorological conditions to the epidemic activity of respiratory syncytial virus.

Our aim was to obtain knowledge of how meteorological conditions affect community epidemics of respiratory syncytial virus (RSV) infection. To this end we recorded year-round RSV activity in nine cities that differ markedly in geographic location and climate. We correlated local weather conditions with weekly or monthly RSV cases. We reviewed similar reports from other areas varying in climate. Weekly RSV activity was related to temperature in a bimodal fashion, with peaks of activity at temperatures above 24-30 degrees C and at 2-6 degrees C. RSV activity was also greatest at 45-65% relative humidity. RSV activity was inversely related to UVB radiance at three sites where this could be tested. At sites with persistently warm temperatures and high humidity, RSV activity was continuous throughout the year, peaking in summer and early autumn. In temperate climates, RSV activity was maximal during winter, correlating with lower temperatures. In areas where temperatures remained colder throughout the year, RSV activity again became nearly continuous. Community activity of RSV is substantial when both ambient temperatures and absolute humidity are very high, perhaps reflecting greater stability of RSV in aerosols. Transmission of RSV in cooler climates is inversely related to temperature possibly as a result of increased stability of the virus in secretions in the colder environment. UVB radiation may inactivate virus in the environment, or influence susceptibility to RSV by altering host resistance.

[Neonatal bacterial meningitis in a tertiary treatment center]. / Meningitis bacteriana neonatal en una institución de tercer nivel de atención.

OBJECTIVE: To determine incidence, etiologic agents and clinical manifestations of bacterial meningitis in patients hospitalized in the newborn ward at the Hospital Infantil de Mexico in Mexico City and establish the incidence of meningitis in newborns admitted with respiratory distress syndrome (RDS) and determine how often blood cultures are negative in bacterial meningitis in this population. METHODS: Retrospective chart review of patients with bacterial meningitis admitted to our hospital. STUDY PERIOD: January 1990-July 1995. RESULTS: There were 959 admissions to the neonatal intensive care unit (NICU). The overall incidence of bacterial meningitis was 32.3/1000 admissions; however, among 170 patients with RDS, [corrected] meningitis was detected in one (5.9/1000 RDS patients). Of the 31 patients with bacterial meningitis, 10 were preterm (PT) and 21 term (T). In the cerebrospinal fluid (CSF) isolates, there was a predominance of gram negative rods (n: 19; 61%). Clinical findings associated to meningitis were non-specific and there were no differences between PT and T infants. From 31 patients, 19 had negative blood cultures at the time of diagnosis (61%). Mortality associated to bacterial meningitis was [corrected] 40% and 23%, for PT and T, respectively (p = NS). CONCLUSIONS: The incidence of bacterial meningitis in the study population was high. Most isolates in CSF were gram-negative rods. Clinical findings in meningitis were non-specific and there were no differences between PT and T. Most of the patients (61%) had negative blood cultures at the time of diagnosis.

[Neonatal herpetic encephalitis. Current concepts concerning a case]. / Encefalitis herpética neonatal. Conceptos actuales a propósito de un caso.

We describe a newborn patient with herpes simplex infection localized to the central nervous system. The diagnosis was suspected on clinical grounds and it was corroborated by tissue culture isolation of the virus and by herpes simplex glycoprotein B DNA detection by PCR in cerebrospinal fluid. We describe the clinical manifestations of this patient and we present some considerations regarding pathogenesis, diagnosis, prognosis and treatment of this viral infection in the newborn period.

[Outbreak of respiratory syncytial virus at a neonatal intensive care unit in Mexico City]. / Brote de infección por virus sincicial respiratorio en una Unidad de Cuidados Intensivos Neonatales en la Ciudad de México.

RSV can be spread in hospital wards, being thus responsible for increased morbidity and mortality among infected patients. We describe an RSV outbreak in a Neonatal Intensive Care Unit (NICU). METHODS. As soon as the first RSV cases were detected in the NICU, every patient, as well as the personnel taking care of them, were tested; nasal washes for viral isolation, and nasopharyngeal swabs for viral antigen detection by immunofluorescence, were collected. RESULTS. Twelve patients were hospitalized. RSV was detected in eight, coinfection was observed in three of them. RSV was also detected in three adults. We describe the clinical findings among the RSV infected patients, and the infection control measures that we followed to stop the RSV spread. CONCLUSIONS. Viruses can be responsible for nosocomial infections, being thus mandatory to establish the diagnosis, treatment and infection control measures. In our NICU, the RSV infected patients had mild to moderate disease, there were no deaths attributable to RSV infection. We discuss infection control measures.