ABSTRACT
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Subject(s)
Humans , Male , Female , Child , Enterovirus/isolation & purification , Enterovirus/pathogenicity , Enterovirus Infections/complications , Enterovirus Infections/epidemiology , Cross Infection/complications , Cross Infection/diagnosis , Community-Acquired Infections/epidemiology , Enterovirus Infections/prevention & control , Enterovirus Infections/therapy , Enterovirus Infections/transmission , Cross Infection/transmission , Community-Acquired Infections/prevention & control , Community-Acquired Infections/transmissionABSTRACT
BACKGROUND: Nitrogen dioxide (NO(2)) has been related to respiratory infections in experimental studies but its role remains controversial in general population studies of children. We aim to assess the association between indoor NO(2) and lower respiratory tract infections (LRTI) during the first year of life in a multicentre prospective cohort study. METHODS: Children (n = 1611) were recruited prior to birth for the Asthma Multicentre Infants Cohort Study (AMICS). Three concurrent cohorts (Ashford, Kent [UK]; Barcelona city, and Menorca Island [Spain]) followed the same research protocol. NO(2) was measured with passive diffusion tubes placed in the living room for 2 weeks when infants were approximately 3 months old. Doctor-diagnosed LRTI during the first year of life (as well as antibiotic use) were measured by questionnaire, and in Ashford validated by the examination of clinical records. In Barcelona, direct measurements using nasopharyngeal lavage and cultures within a continuous surveillance system were done. RESULTS: The cumulative rates of LRTI (39% in Ashford, 28% in Barcelona, and 45% in Menorca) were unrelated to NO(2) levels (corresponding medians 6, 46, and 12 ppb, respectively) in all three centres (all odds ratios being around 1). Similarly, the rates of LRTI in Barcelona measured with the continuous record showed no association with NO(2) (all rate ratios being below 1). In addition, there was no association between rate of antibiotics courses per year per child (2.4 in Ashford, 1.7 in Barcelona, 0.9 in Menorca) and NO(2) levels. CONCLUSIONS: Indoor NO(2) at current levels does not seem to be involved in increasing respiratory infections by itself in infants, suggesting that the effects observed in studies on outdoor air are probably due to other copollutants.
Subject(s)
Air Pollutants/analysis , Air Pollution, Indoor/analysis , Nitrogen Dioxide/analysis , Respiratory Tract Infections/etiology , England/epidemiology , Female , Fossil Fuels/adverse effects , Household Articles , Humans , Incidence , Infant , Male , Prospective Studies , Respiratory Tract Infections/epidemiology , Spain/epidemiologyABSTRACT
The relationship between cases of persistent diarrhoea and the levels and type of human astrovirus was investigated. The potential correlation between human astrovirus excretion levels and the occurrence of protracted gastroenteritis was elucidated after quantifying astroviruses in faecal samples by a competitive RT-PCR. This assay was developed employing an internal RNA standard constructed for this purpose and showed a threshold of positivity of 3.4 x 10(4) genomes per gram of faeces. By this procedure, the levels of astrovirus, belonging to serotypes 1, 2, 3, 4, and 8, in faecal samples could be ascertained to range from 3.4 x 10(8) to 1 x 10(13) per gram of faeces. The mean viral titre in the serotype 3-containing faeces was higher than in any of the other serotype-containing samples. In children with no background disease, persistent gastroenteritis cases were detected in 8.5% of the astrovirus infections, and 37.5% of those were associated with astrovirus type 3 infection. In addition, 42.9% of astrovirus 3 isolates were implicated with persistent cases, some of them lasting for 3 months. Other type 3 isolates, detected in the faeces in very large numbers, caused severe gastroenteritis.
Subject(s)
Diarrhea/epidemiology , Feces/virology , Gastroenteritis/epidemiology , Mamastrovirus/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction/methods , Astroviridae Infections/epidemiology , Astroviridae Infections/virology , Centrifugation, Density Gradient , Child , Child, Preschool , Diarrhea/virology , Gastroenteritis/virology , Humans , Incidence , Mamastrovirus/classification , Mamastrovirus/genetics , RNA, Viral/analysis , Reference Standards , SerotypingABSTRACT
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Subject(s)
Child, Preschool , Child , Humans , Spain , Tracheitis , Cohort Studies , Prevalence , Chlamydophila pneumoniae , Pneumonia, Bacterial , Prospective Studies , Chlamydophila Infections , Bronchitis , Asthma , Bronchiolitis , Laryngitis , Follow-Up StudiesABSTRACT
Fundamento. El estudio etiológico del síndrome pertusoide, no sólo en cuanto concierne al género Bordetella, sino aplicándolo a otros microorganismos, durante un período de 11 años (1988-1998). Métodos. En todas las muestras de pacientes con tos pertusoide se investigó la presencia de Bordetella spp., otras bacterias, virus y micoplasmas. Los datos analizados incluyeron los resultados microbiológicos, así como aspectos epidemiológicos (edad, sexo, área de ingreso hospitalario, distribución anual y período estacional). Resultados. Se analizaron un total de 1.063 muestras la mayoría aspirados nasofaríngeos (910), correspondientes a 905 pacientes, y en el 56,9 por ciento de éstos se obtuvo un cultivo positivo. B. pertussis se aisló en el 10,5 por ciento de los pacientes y entre las otras bacterias destacaron Haemophilus influenzae con un 16,9 por ciento y Streptococcus pneumoniae con un 15,8 por ciento. El virus respiratorio sincitial se encontró en el 10,7 por ciento de los enfermos y los demás virus en el 9,4 por ciento de ellos. Entre los micoplasmas destacaba Ureaplasma urealyticum con un 2,9 por ciento de positividad. Cuatrocientos noventa y cinco pacientes eran varones y 410 mujeres, el 67,2 por ciento tenían entre 0 y 6 meses de edad y requirieron ingreso hospitalario 689 pacientes (76,1 por ciento). Los aislamientos de B. pertussis y adenovirus predominaron en primavera y verano, en contraste con H. influenzae, S. pneumoniae y virus respiratorio sincitial que fueron más frecuentes en los meses de invierno. Conclusiones. El mayor número de pacientes con síndrome pertusoide son niños menores de seis meses de edad. Los porcentajes de aislamiento de B. pertussis y virus respiratorio sincitial son idénticos, con lo que nos parece indiscutible la necesidad de su investigación en este cuadro clínico. La búsqueda de otros microorganismos está también justificada, ya que la sintomatología clínica es frecuntemente inespecífica en los lactantes (AU)
