[PCR testing for Bordetella pertussis in household contacts as a diagnostic tool for atypical whooping cough in unvaccinated young infants]. / La recherche de Bordetella pertussis par PCR chez les parents permet de diagnostiquer la coqueluche atypique chez les jeunes nourrissons non vaccinés.

INTRODUCTION: False-negative findings of polymerase chain reaction (PCR) for genuine pertussis as well as the numerous atypical forms of whooping cough make it difficult to diagnose this disease in young babies. METHODS: For two years, real-time PCR was performed to test for Bordetella pertussis in 86 infants younger than 6 months hospitalized for apnea or paroxysmal and/or vomiting cough and in 205 of their household contacts, whether or not they coughed. RESULTS: Group 1 included 30 infants for whom PCR detected B. pertussis (25 of whom were also RSV+). PCR was also positive for at least one household contact in 25/30 families. This group included 16 babies with apnea and 12 who developed a whooping cough during follow-up. Group 2 comprised 12 infants whose PCR was negative while at least one household contact had positive results. Five of these infants had severe apnea and 6 developed a whooping cough. Group 3 included 44 infants (28 RSV +) for whom PCR was negative in the index case and in the household contacts: none developed a whooping cough during follow-up. Only 3 of the 54 positive household contacts had a paroxysmal cough or a typical whooping cough and 12 had no cough at all. CONCLUSION: Positive PCR in a household contact, symptomatic or not, is helpful for the diagnosis of atypical whooping cough in young infants.

[Respiratory syncytial virus in hospitalized children. A 3-year study]. / La fréquence du virus respiratoire syncytial et des autres virus respiratoires dans les hospitalisations de l'enfant. Une enquête de 3 ans.

OBJECTIVE: To assess the prevalence of respiratory syncytial virus (RSV) and other important respiratory viruses in children hospitalized in a pediatric hospital in Paris (France) during a 3-year period (2001 to 2004). PATIENTS AND METHODS: The study included all patients aged 8 days to 16 years admitted from the community through emergency department with bronchiolitis, pneumonia, upper respiratory tract infection, asthma or acute isolated fever and who had nasopharyngeal samples taken for viral identification by immunofluorescence (RSV, influenza, para-influenza, and adenoviruses). RESULTS: A virus was found in 464 of 1208 patients with samples taken. RSV was identified in 375 patients, 74% of them younger than 6 months and diagnosed with bronchiolitis. RSV was isolated more often than any other virus, overall and for all diagnoses except "isolated fever," for which influenza was more frequent. In patients aged 24 months or older, influenza and RSV were identified at the same frequency. Overall, influenza virus was found in 53 patients, adenoviruses in 24 and para-influenza viruses in 11. CONCLUSION: RSV was the respiratory virus isolated most often, even in older children, during this 3-year study. The relative rarity of hospitalizations due to para-influenza viruses is characteristic of this area, compared with some other countries.

Pertussis and respiratory syncytial virus infections.

During the winter 2005-2006, all infants <4 months of age admitted for bronchiolitis or acute respiratory tract infection in a tertiary care pediatric hospital in Paris were tested for respiratory syncytial virus (RSV) and pertussis with real-time polymerase-chain reaction (RT-PCR). A positive pertussis-PCR was found in 14/90 (16%) infants infected with RSV and in 5/30 negative for RSV. Similar clinical symptoms were found in all RSV-positive infants with or without pertussis co-infection. Most infants (73%) were not vaccinated against pertussis, and the other children had received one or two injections. In conclusion, pertussis-RSV co-infection is common in young infants, and pertussis-PCR should be used, whenever available.

Human bocavirus infection in hospitalized children during winter.

Human bocavirus (HBoV) has recently been described as a common agent of acute upper and lower respiratory tract infections in children. We screened by polymerase chain reaction for HBoV nucleic acid nasopharyngeal aspirates from hospitalized children with negative culture and immunofluorescence assay for respiratory syncytial virus, influenza viruses, adenovirus, and parainfluenza viruses. HBoV was detected in 32 children (5.5%) and was the second virus identified in nasopharyngeal aspirates after respiratory syncytial virus. Most of the children had severe disease.