Zanamivir for treatment of symptomatic influenza A and B infection in children five to twelve years of age: a randomized controlled trial

BACKGROUND

Influenza infection rates are higher in children than in other age groups. This study evaluated the efficacy, safety and tolerability of a 5-day course of twice daily inhaled zanamivir, 10 mg, compared with placebo in the treatment of symptomatic influenza A and B viral infections among children 5 to 12 years of age.

METHODS

This double blind, randomized, placebo-controlled, parallel group, multicenter study conducted in the Northern Hemisphere during the 1998 and 1999 influenza season enrolled 471 patients with influenza-like symptoms for < or = 36 h. Patients were randomly assigned to zanamivir (n = 224) or placebo (n = 247). Symptoms were recorded on diary cards twice daily during treatment, for 9 days after treatment and for 14 additional days (if still reporting moderate/severe cough and/or taking relief medication).

FINDINGS

A total of 346 (73%) patients were influenza-positive by culture, serology or polymerase chain reaction (65% influenza A, 35% influenza B). Zanamivir reduced the median time to symptom alleviation by 1.25 days compared with placebo among patients with confirmed influenza infection (P < 0.001). Zanamivir-treated patients returned to normal activities significantly faster and took significantly fewer relief medications than placebo-treated patients. Zanamivir was well-tolerated, demonstrating adverse event profiles similar to those of placebo and no clinically significant changes in laboratory findings. Viral susceptibility testing revealed no zanamivir-resistant strains of influenza A or B.

CONCLUSIONS

Zanamivir was effective in shortening the duration and severity of influenza symptoms and was well-tolerated among children 5 to 12 years of age.

Characterization of the Moraxella catarrhalis uspA1 and uspA2 genes and their encoded products

The uspA1 and uspA2 genes of M. catarrhalis O35E encode two different surface-exposed proteins which were previously shown to share a 140-amino-acid region with 93% identity (C. Aebi, I. Maciver, J. L. Latimer, L. D. Cope, M. K. Stevens, S. E. Thomas, G. H. McCracken, Jr., and E. J. Hansen, Infect. Immun. 65:4367-4377, 1997). The N-terminal amino acid sequences of the mature forms of both UspA1 and UspA2 from strain O35E were determined after enzymatic treatment to remove the N-terminal pyroglutamyl residue that had blocked Edman degradation. Mass spectrometric analysis indicated that the molecular mass of UspA1 from M. catarrhalis O35E was 83,500 +/- 116 Da. Nucleotide sequence analysis of the uspA1 and uspA2 genes from three other M. catarrhalis strains (TTA24, ATCC 25238, and V1171) revealed that the encoded protein products were very similar to those from strain O35E. Western blot analysis was used to confirm that each of these three strains of M. catarrhalis expressed both UspA1 and UspA2 proteins. Several different and repetitive amino acid motifs were present in both UspA1 and UspA2 from these four strains, and some of these were predicted to form coiled coils. Linear DNA templates were used in an in vitro transcription-translation system to determine the sizes of the monomeric forms of the UspA1 and UspA2 proteins from strains O35E and TTA24.

A longitudinal study of otitis media with effusion among 2- to 5-year-old African-American children in child care

OBJECTIVE

To prospectively document the prevalence of otitis media with effusion (OME) in 86 African-American children between ages 2 and 5 years.

STUDY DESIGN

Eighty-six children in center-based child care whose ear status had been followed from infancy continued to be observed. Middle ear status was assessed by pneumatic otoscopy and tympanometry biweekly.

RESULTS

The prevalence of OME decreased as children became older. The mean proportion of examinations demonstrating bilateral OME (BOME) ranged from 12% between 24 to 30 months to 4% between 54 to 60 months of age. The mean proportion of exams revealing bilateral normal ears increased from 77% at 24 to 30 months to 88% at 54 to 60 months of age. Although 60 children had experienced BOME that lasted 4 months or longer in the 6- to 24-month age period, only 8 of these children experienced at least 4 months of continuous BOME between 24 to 60 months.

CONCLUSIONS

The proportion of time with BOME decreased progressively with increasing age in this population. Only 8 of 60 children who had experienced more than 4 consecutive months of BOME before 2 years of age continued to manifest persistent effusion or experience recurrences of prolonged BOME after 2 years of age.

Otitis media, the caregiving environment, and language and cognitive outcomes at 2 years

OBJECTIVE

To examine the relationship between otitis media with effusion (OME) and associated hearing loss between 6 and 24 months of age and children's language and cognitive development at 2 years of age.

STUDY DESIGN

A prospective cohort design in which 86 African-American infants who attended group child-care centers were recruited between 6 and 12 months of age. Between 6 and 24 months, assessments included serial ear examinations using otoscopy and tympanometry, serial hearing tests, two ratings of the childrearing environment at home and in child care, and language and cognitive outcomes at 2 years.

RESULTS

Children experienced either unilateral or bilateral OME an average of 63% and reduced hearing sensitivity an average of 44% of the time between 6 and 24 months of age. Although proportion of time with OME or with hearing loss was modestly correlated with measures of language and cognitive skills, these relationships were no longer significant when the ratings of the home and child-care environments were also considered. Children with more OME or hearing loss tended to live in less responsive caregiving environments, and these environments were linked to lower performance in expressive language and vocabulary acquisition at 2 years.

CONCLUSIONS

Both OME and hearing loss were more strongly related to the quality of home and child-care environments than to children's language and cognitive development. Study results might be explained either by suggesting that children in less responsive caregiving environments experience conditions that make them more likely to experience OME and/or by suggesting that it may be more difficult for caregivers to be responsive and stimulating with children with more OME.

RSV infection of human airway epithelial cells causes production of the beta-chemokine RANTES

Infection of airway epithelial cells with respiratory syncytial virus (RSV) results in the production of a restricted number of cytokines, which may modulate the inflammatory response to infection. To get a better understanding of epithelial cell-mediated inflammatory processes in RSV disease, the aim of the present study was to identify the production of mononuclear cell/eosinophil/mast cell inflammatory chemokines [monocyte chemotactic protein (MCP)-1, MCP-3, macrophage inflammatory protein-1beta, and RANTES] during productive RSV infection in airway epithelial cells. Normal human primary bronchial epithelial cell cultures, nasal epithelial cell explants, and the BEAS-2B airway epithelial cell line were inoculated with RSV, and chemokine induction was assessed during the phase of logarithmic increase in infectious virus production. Only RANTES was found to increase in epithelial cell cultures in an infection-dependent manner. Furthermore, RANTES was released only by RSV-producing cells. To determine whether RANTES was induced by RSV infection in vivo, RANTES was measured in nasal lavage fluids (NLF) from children with RSV-positive and RSV-negative upper respiratory infection and children when they were well. RANTES was increased significantly during RSV infection (128 +/- 38 pg/ml NFL) compared with non-RSV infection (42 +/- 12 pg/ml NFL) and with asymptomatic baseline (13 +/- 4 ng/ml NFL) in the same children. Because RANTES is an effective eosinophil and memory T cell chemoattractant and activator and because eosinophil-dominated inflammation is a hallmark of asthmatic airways, RANTES may play a role in the pathogenesis of RSV-induced exacerbations of airway reactivity and wheezing.

Prospective surveillance for otitis media with effusion among black infants in group child care

OBJECTIVE

To document the prevalence of otitis media with effusion (OME) in 102 black children observed prospectively between 6 and 24 months of age.

METHODS

Study children attended nine different center-based child care facilities. Middle ear status was assessed by pneumatic otoscopy and tympanometry every 2 weeks.

RESULTS

All children, except one, had OME during the period of observation. The proportion of child-examinations revealing bilateral OME ranged from 76% between 6 and 12 months of age to 30% between 21 and 24 months of age. Effusions were considered purulent in only 13% of examinations revealing middle ear fluid. The mean incidence of purulent OME was 2.13 episodes per child per year. Sixty-six children had at least 4 months of continuous bilateral OME during the period of observation; 57 were followed without placement of tympanostomy tubes. Bilateral OME had resolved before the second birthday in 95% of these children, and within 3 months of achieving the 4-month criterion in 50% of subjects.

CONCLUSIONS

Persistent bilateral OME occurs commonly between 6 and 18 months of age in infants who enter group child care during the first year of life. In this study, spontaneous resolution of bilateral effusion by 2 years of age was typical.

Nasal lavage cytokines in normal, allergic, and asthmatic school-age children

Inflammation can be demonstrated in the airway mucosa of asthmatics, even in the absence of overt symptoms, but the pathogenesis of this chronic inflammation is incompletely defined. It has been suggested that inflammatory cytokines produced by epithelium may play important roles in this process. Therefore, we measured the cytokines interleukin-8 (IL-8), IL-6, and granulocyte-macrophage colony-stimulating factor (GM-CSF) in nasal lavage fluids from school-age children who were (1) "normal" (nonallergic/nonasthmatic), (2) allergic to house-dust mite antigen but nonasthmatic (no history of wheezing), or (3) allergic and asthmatic (history of > or = 10 wheezing episodes). Children underwent a single nasal lavage procedure while asymptomatic and on no anti-inflammatory medications or anti-histamines. In addition to cytokine concentrations, cell counts, differentials, albumin, histamine, and eosinophil cationic protein (ECP) concentrations were determined in nasal lavage fluids. Significant increases in IL-8 and ECP were observed in asthmatics compared with both normals and allergic nonasthmatics. Overall, IL-8 in nasal lavage fluids correlated significantly with ECP. Allergic nonasthmatics did not have significant increases in cytokines or other mediators compared with normal subjects. Concentrations of IL-6 did not differ significantly among the three groups, and GM-CSF was undetectable in all samples tested. We conclude that increased IL-8 production and eosinophil activation are characteristic of the airways of asthmatic children when asymptomatic, and we speculate that IL-8 plays a role in the maintenance of airway inflammation in asthma.

Correlates of recurrent wheezing in school-age children. The Physicians of Raleigh Pediatric Associates

Correlates of recurrent wheezing were examined in a case-control study involving 343 children ranging from 7 to 12 yr of age and recruited from a general pediatric practice. Positive skin tests for allergy were observed in 35% of a random sample of children without recurrent wheezing, and in 77% and 90% of children who had experienced from two to four episodes and five or more episodes, respectively, of recent wheezing. By logistic regression analysis, sensitization to dust mite (odds ratio [OR]: 5.2; 95% CI: 3.0 to 9.0), cat (OR: 15.5; 95% CI: 3.4 to 70.8), and Alternaria (OR: 6.8; 95% CI: 2.1 to 21.5) antigens was consistently associated with recurrent wheezing. Sensitization to pollen antigen(s), observed in 60% of allergic children, was not associated with wheezing. A family history of asthma was a significant predictor of recurrent wheezing (OR: 3.2; 95% CI: 1.7 to 5.9) after adjusting for its association with positive skin tests. Environmental tobacco smoke (ETS) exposure was associated with an increased risk of recurrent wheezing in nonallergic children and in allergic females, but not in allergic males. ETS exposure was not associated with positive skin tests for allergy. A history of wheezing with respiratory illness before 2 yr of age was associated with a modest risk of recurrent wheezing between 7 and 12 yr of age (OR: 2.3; 95% CI: 1.2 to 4.6), a risk that did not differ by allergic status or gender. Theoretically, the prevalence of recurrent wheezing in this population could be reduced approximately 65% by controlling exposure to indoor allergens and ETS.

Transmission of multidrug-resistant serotype 23F Streptococcus pneumoniae in group day care: evidence suggesting capsular transformation of the resistant strain in vivo

Surveillance for nasopharyngeal colonization with Streptococcus pneumoniae was maintained in a research day care center between 1985 and 1992. An outbreak of nasal carriage of a multi-drug-resistant (MDR) serotype 23F organism occurred between May 1990 and December 1991 involving 14 of 52 children. Electrophoresis of penicillin-binding proteins (PBP) and pulsed-field gel electrophoresis (PFGE) of chromosomal DNA indicated that the MDR serotype 23F organism was closely related to a serotype 23F MDR clone that has been prevalent in Spain since the early 1980s. In June 1991, an MDR serotype 14 organism was isolated from a child who had previously carried the MDR serotype 23F strain. PFGE and PBP typing revealed that the MDR serotype 14 organism was very similar to the circulating MDR serotype 23F strain, suggesting serotype transformation. Dissemination of MDR pneumococcal strains and possibly spread of the MDR phenotype to additional serotypes may be facilitated in group day care.

Otitis media, hearing sensitivity, and maternal responsiveness in relation to language during infancy

The relation of otitis media with effusion (OME) and associated hearing loss to language and cognitive skills at 1 year of age was studied to determine whether OME-related hearing loss had a direct association with language and cognitive outcomes at 1 year of age or an indirect association with these outcomes, as mediated by the child-rearing environment. Subjects were 61 black infants attending community-based child care programs. The presence of OME was assessed biweekly from 6 to 12 months of age by otoscopy and tympanometry. Hearing was assessed with visual reinforcement audiometry when children were well and when ill with OME. Language and cognitive skills and the child-rearing environment at home and in child care were examined. The results indicated a modest correlation between hearing loss associated with OME and receptive language. However, the direct association between OME-related hearing loss and all the language and cognitive measures was negligible. Hearing loss had an indirect association with receptive and expressive language, cognitive development, and overall communication as mediated by child-rearing factors. That is, children with more frequent hearing loss tended to have less responsive mothers and home environments, and this association was linked to lower performance on the infant assessments.

Nasal cytokine production in viral acute upper respiratory infection of childhood

Children in a day care center underwent serial nasal lavages in order to assess nasal cytokine expression during acute upper respiratory infections (URI). Interleukin (IL)-1 beta, IL-8, IL-6, and tumor necrosis factor-alpha (TNF-alpha) were markedly elevated in nasal lavage fluid during acute URI compared to baseline, and all except TNF-alpha decreased significantly by 2-4 weeks later. Cytokine patterns in respiratory syncytial virus-positive and -negative illnesses did not differ significantly. A subgroup of children also underwent superficial mucosal biopsy under the inferior nasal turbinate. During acute URI, biopsy cells (90%-95% epithelial) showed increased transcripts for IL-1 beta, IL-8, and IL-6 in 7 of 9 subjects, suggesting that epithelial cells may be one source of cytokines during acute URI. The results show that inflammatory cytokines are elevated in nasal secretions during acute URI in preschool children. Thus, cytokines are likely to participate in regulation of respiratory virus-induced inflammation.

Passive smoking and middle ear effusion among children in day care

One hundred thirty-two children who attended a research day-care center were studied to determine whether passive tobacco smoke exposure was associated with an increased rate of otitis media with effusion or with an increased number of days with otitis media with effusion during the first 3 years of life. Based on preliminary studies, a serum cotinine concentration of greater than or equal to 2.5 ng/mL was considered indicative of exposure to tobacco smoke. Otitis media with effusion was diagnosed using pneumatic otoscopy by nurse practitioners and pediatricians who reviewed the children's health status each weekday. The 87 children with serum cotinine concentrations greater than or equal to 2.5 ng/mL had a 38% higher rate of new episodes of otitis media with effusion during the first 3 years of life than the 45 children with lower or undetectable serum cotinine concentrations (incidence density ratio = 1.38, 95% confidence interval 1.21 to 1.56). The average duration of an episode of otitis media with effusion was 28 days in the children with elevated cotinine concentrations and 19 days in the children with lower cotinine concentrations (P less than .01). It is estimated that 8% of the cases of otitis media with effusion in this population and 17.6% of the days with otitis media with effusion may be attributable to exposure to tobacco smoke.

Respiratory allergy and the relationship between early childhood lower respiratory illness and subsequent lung function

In a study of 159 school-age children whose histories of outpatient visits for lower respiratory illness (LRI) had been documented from early infancy, we observed lower mean levels of small airway function in boys who had experienced two or more episodes of wheezing-associated LRI before 6 yr of age. To determine whether allergy was an important factor influencing this result, we examined relationships among the results of RAST tests for seven common inhalant allergens and concurrent lung function in 126 subjects who consented to venipuncture. Increasing values for the sum of scores for the seven RAST tests were associated with progressively lower mean levels of small airways function in boys with histories of recurrent wheezing LRI during the preschool years. The association of allergy with lower levels of lung function was largely accounted for by dust mite allergy. RAST results were not correlated with lung function in boys who had experienced zero or 1 wheezing LRI before 6 yr of age or in girls. A history of recurrent wheezing LRI during the preschool years was also associated with significantly lower mean levels of small airways function in boys who had negative RAST tests. A subset of 49 boys was reevaluated after an average interval of 4 yr with RAST tests, spirometry, and methacholine challenge. Dust mite allergy was associated with an increased prevalence of bronchial hyperreactivity independent of early childhood wheezing LRI history.(ABSTRACT TRUNCATED AT 250 WORDS)

Herpes simplex type 1 infections in group day care

To characterize patterns of herpes simplex virus type 1 infection, illness and transmission among children in group day care, the data for 115 children who had been followed longitudinally from early infancy in a research day care center were examined. By 5 years of age 37% of study children had evidence of herpes simplex virus type 1 infection as demonstrated by virus isolation and/or seroconversion. The incidence of infection was highest among children 1 to 2 years old. Four small clusters of primary infections were observed over the 12-year study period but no cluster involved more than 6 children. Fifty-five percent of primary infections occurred during these small outbreaks; the remainder were sporadic. Gingivostomatitis was observed in 26% of children with primary culture-proved infections; no child with infection identified solely by serologic means had a history of gingivostomatitis. The occurrence of gingivostomatitis did not appear to be associated with increased transmission of herpes simplex virus type 1 infection in this day-care setting.

In vitro activity of orally administered antimicrobial agents against Haemophilus influenzae recovered from children monitored longitudinally in a group day-care center

To determine whether the prevalence of resistance to commonly used oral antimicrobial agents varied over time, we compared the in vitro susceptibilities of 217 strains of Haemophilus influenzae recovered from nasopharyngeal secretions of children in a day-care center studied longitudinally between 1979 and 1987. The overall rate of beta-lactamase production in these strains was 18%, with rates of 57% in type b isolates (n = 21) and 14% in non-type b isolates (n = 196). The percentages of isolates for which MICs were less than or equal to 1.0 micrograms/ml for amoxicillin alone, amoxicillin in combination with clavulanic acid, and cefuroxime alone were 82, 92, and 93%, respectively. The percentage of strains for which cefaclor MICs were less than or equal to 1.0 micrograms/ml was only 0.5%. Isolates for which chloramphenicol MICs were greater than 2.0 micrograms/ml or for which trimethoprim-sulfamethoxazole MICs were greater than 0.5/9.5 micrograms/ml were uncommon: 1 and less than 1%, respectively. High concentrations of erythromycin alone and in combination with sulfisoxazole were required to inhibit the majority of test strains; there was no evidence of erythromycin-sulfisoxazole synergy. In vitro susceptibility to commonly used oral antimicrobial agents remained at a constant level when H. influenzae isolates collected from children in a day-care center during 1979 through 1983 were compared with strains collected during 1984 through 1987.

Lung function in school-age children who had mild lower respiratory illnesses in early childhood

We examined the relationship between patterns of mild lower respiratory illness (LRI) experienced in early childhood and lung function in 89 boys and 70 girls 6 to 18 yr of age. The children's histories of outpatient visits for wheezing and nonwheezing LRI during the first 6 yr of life had been documented by physicians in a single pediatric practice. Most children were reported by their parents to have been free of recurrent respiratory symptoms during the 2 yr prior to lung function testing. In sex-specific analyses, average lung function assessed by spirometry was similar in children who had made zero or one physician visit for wheezing LRI during the preschool years. Boys who had experienced two or more episodes of wheezing LRI during the preschool years had lower average FEV1, FEV1/FVC, FEF25-75, Vmax50, and Vmax75 than did boys who had zero or one preschool wheezing illness. The association between recurrent preschool wheezing LRI and later lung function remained after exclusion of data from seven boys who were reported to have wheezed in the 2 yr prior to study. Girls who had experienced two or more preschool wheezing LRI had lower average FEF25-75 and Vmax50 than girls with a history of zero or one such illness, but differences were not statistically significant. Recurrent nonwheezing LRI during the preschool years was not significantly associated with subsequent lung function in either sex, regardless of preschool wheezing LRI history. Detailed information concerning early childhood LRI experience is valuable in epidemiologic studies of factors influencing lung function in children.

Group-specific serum antibody responses in children with primary and recurrent respiratory syncytial virus infections

Antigenic group-specific serum antibody responses to first and second respiratory syncytial virus (RSV) infections were studied in children who had been followed longitudinally from early infancy in a research day-care center. Plaque-reduction neutralizing (PRN) antibody assays and ELISAs for the fusion (F) and attachment (G) glycoproteins were done using antigens of prototype RSV strains from groups A and B. Responses to antigens of viruses homologous and heterologous to the antigenic group of the infecting viral strain were compared. Primary group A infection elicited antibodies cross-reactive with group B virus in the PRNB and the ELISAS for GB and FB. In contrast, primary group B infection induced significant increases in mean concentrations of antibody cross-reactive with group A virus only in the FA ELISA. Second RSV infections caused by group B viruses in children with histories of primary group A infection induced heterologous rises in the PRNA and GA assays, suggesting that prior group A infection had primed for a more extensive cross-reacting antibody response at the time of second RSV infections with group B viruses.

Home air nicotine levels and urinary cotinine excretion in preschool children

We examined the extent of correlation between home air nicotine levels and urine cotinine/creatinine ratios (CCR) in 27 children who attended a research day care program where they were not exposed to environmental tobacco smoke (ETS) during the daytime hours. Average concentrations of nicotine in home air were determined by active air sampling during the evening and night hours on 2 consecutive days. Urine samples for cotinine and creatinine determinations were collected before, during, and after the two sampling periods. In addition, four sequential weekly urine samples for CCR were obtained from study children to determine the extent to which single determinations of CCR were representative for individual children. Fifteen children resided in homes with smokers, and 12 did not. Urine CCR consistently distinguished most exposed and unexposed children. However, three exposed children had urine CCRs that clustered routinely around the criterion CCR (30 ng/mg cotinine-creatinine) that best distinguished exposed and unexposed children. In children exposed to ETS in the home, there was a significant correlation between average home air nicotine levels and the average logarithm of urine CCR the two mornings after the home air monitoring periods (r = 0.68; p = 0.006). In study children, urine CCRs were remarkably stable over the 1-month observation period. Rank correlation coefficients for sequential weekly determinations of CCR were consistently greater than r = 0.88; p less than 0.0001.

Otitis media in early childhood and cognitive, academic, and classroom performance of the school-aged child

The relationship between the occurrence of otitis media during the first 3 years of life and cognitive, academic, and classroom performance during the third year of elementary school was evaluated in 44 socioeconomically disadvantaged children. The children attended a research day-care program where their otitis media experience and psychoeducational development were documented prospectively from birth. No significant relationship was found between otitis media in early childhood and performance on tests of verbal intelligence or academic achievement in the third year of school. The number of days of otitis media before 3 years of age was significantly correlated with teachers' ratings of children's attentional behavior in the classroom, however. Children with more early otitis media tended to be rated as less task oriented and less able to work independently than children with less otitis media. This was an exploratory study of a small number of children. Further study of the potential association is needed.

Serum immunoglobulin G antibody subclass response to respiratory syncytial virus F and G glycoproteins after first, second, and third infections

Serum samples from 31 children who experienced two or three infections with respiratory syncytial virus (RSV) in the first four years of life were tested in an enzyme-linked immunosorbent assay to examine the immunoglobulin G (IgG) subclass responses to the RSV F and G surface glycoproteins associated with primary infection and reinfection. We sought to determine whether the greater degree of glycosylation of the G glycoprotein was reflected in an IgG subclass immune response more like that to a polysaccharide antigen than to a protein antigen. We found that the IgG1/IgG2 ratio of postinfection antibody titers to F was fourfold higher than that to the G glycoprotein after RSV infections 1, 2, and 3. The IgG2 response to the heavily glycosylated G glycoprotein differed from that to a polysaccharide antigen in that the IgG1/IgG2 ratio remained constant with age, whereas the response to a polysaccharide antigen decreased as the IgG2 response increased with age. We also noted that antibody responses to both surface glycoproteins in the IgG1 and IgG2 subclasses reached their maximum levels after RSV infection 2.

Otitis media in early childhood and its relationship to later phonological development

The relationship between otitis media during the first 3 years of life and subsequent speech development was examined in 55 socioeconomically disadvantaged children who attended a research day-care program. The children were participants in a longitudinal study of child development in which the number of episodes of otitis media and the duration of each otitis episode were reported prospectively from infancy. Standardized tests of speech were administered between the ages of 2 1/2 and 8 years. No significant relationship was found between otitis media in early childhood and number of common phonological processes or consonants in error used during the preschool years. However, the number of days of otitis media before age 3 was associated with the total number of phonological processes used by children between the ages of 4 1/2 and 8 years. Although these findings suggest that phonological processes after age 4 1/2 tend to drop out more slowly for children with a history of otitis media than of children without histories, no consistent patterns were observed for individual phonological processes or for the total number of consonants in error in this age range.

Experimental rhinovirus infection in human volunteers exposed to ozone

We studied 24 young adult male volunteers experimentally inoculated with type 39 rhinovirus to determine whether the course of viral infection was modified by exposure to moderate levels of ozone (0.3 ppm for 6 h per day) over the 5 days after virus inoculation. No differences in rhinovirus titers in nasal secretions, recruitment of neutrophils into nasal secretions, levels of interferon in nasal lavage fluid, in vitro lymphocyte proliferative responses to rhinovirus antigen, or levels of convalescent serum neutralizing antibody to type 39 rhinovirus were demonstrated in relation to ozone exposure. The level and pattern of ozone exposure used in this experiment had no demonstrable adverse effects on the immune responses necessary to limit and terminate rhinovirus infection of the upper respiratory tract.

Lower respiratory illness in early childhood and lung function and bronchial reactivity in adolescent males

We examined the relationship between lower respiratory illness (LRI) experience in early childhood and lung function and bronchial reactivity in 57 boys, 11 to 22 yr of age, whose histories of outpatient physician visits for wheezing and nonwheezing LRI had been documented prospectively during their first 6 yr of life. These boys were a subpopulation of 159 children whose early childhood LRI experience and spirometric performance had been studied an average of 4 yr previously. The majority of boys had been free of chronic respiratory symptoms in the 2 yr before evaluation. Boys with histories of 2 or more preschool wheezing illnesses had lower mean levels of performance for FEV1, FEF25-75, FEF50, FEF75, and FEV1/FVC than did boys who had zero or 1 preschool wheezing illness, replicating observations that had been made when the boys had been studied 4 yr previously. Boys with lower spirometric performance relative to the study population on initial testing continued to have lower relative levels of spirometric performance 4 yr later. Neither preschool wheezing nor nonwheezing illness experience was associated with the degree of methacholine sensitivity measured in adolescence. Increasing degrees of methacholine sensitivity were associated with lower levels of spirometric performance; however, preschool wheezing illness experience remained a significant correlate of spirometric performance after adjustment for level of methacholine sensitivity. We conclude that recurrent preschool wheezing illness in these adolescent boys was associated with persistently lower lung function, but not enhanced methacholine sensitivity, during the middle to late school years.

Nasopharyngeal carriage of antibiotic-resistant pneumococci by children in group day care

We compared rates of antibiotic resistance in strains of Streptococcus pneumoniae recovered from nasopharyngeal secretions of a group of children studied longitudinally in a research day care center between 1978 and 1985 and recovered from usually sterile body fluids of patients at a tertiary care hospital between 1981 and 1985. The prevalence of trimethoprim-sulfamethoxazole (TMP-SMZ) resistance was 11.5% in isolates from the hospital, whereas 30.0% of episodes of nasopharyngeal carriage of S. pneumoniae studied in day care children included TMP-SMZ-resistant isolates. The proportion of episodes of colonization with TMP-SMZ-resistant isolates in the day care study increased from 5.4% before 1981 to 39% between 1981 and 1985. Isolates of S. pneumoniae relatively resistant (MIC greater than or equal to 0.125 micrograms/mL) to penicillin G, amoxicillin, or cefuroxime accounted for 8% of isolates from the hospital and 11.9% of episodes of nasopharyngeal colonization in children in day care. Pneumococci with reduced susceptibility to either TMP-SMZ or a beta-lactam antibiotic were recovered from 68% of 72 children in the day care study.

Adenovirus infections and respiratory illnesses in children in group day care

Adenovirus infections and respiratory illnesses among 123 children attending a research day care center were analyzed from data collected prospectively from 1967 through 1981. During the 15-year study period, 298 adenovirus isolates were recovered from respiratory secretions of the study children, and five different serotypes were identified, with types 1, 2, and 5 accounting for 92% of the typed isolates. Annual incidence of each serotype varied greatly, with types 2 and 5 predominating before 1975 and type 1 thereafter. Exposure to adenovirus in the day care center correlated with acquisition of infection. Through two years of age, children were exposed to 3.4 +/- 0.9 (mean +/- SD) different serotypes and became infected by 2.1 +/- 0.8 different types. Most infections occurred before the child's second birthday, and incidence was highest from six to 12 months of age (1.4 primary infections/child-year). Mild and febrile illness accompanied 75% of primary isolations. Otitis media occurred in 37% of illnesses over all ages and in greater than 50% of illnesses among infants.

Pulmonary infections with respiratory syncytial virus and the parainfluenza viruses

Respiratory syncytial virus (RSV) and the parainfluenza viruses (PIVs) are the most important causes of acute lower respiratory illness (LRI) in infants and children under 6 years of age. These enveloped viruses are members of the paramyxovirus family. They infect cells in the epithelium lining the trachea and intrapulmonary airways, and cause croup, bronchitis, bronchiolitis, and bronchopneumonia. RSV causes annual midwinter to early spring outbreaks of respiratory disease in temperate climates; epidemics are heralded by the appearance of increased numbers of cases of bronchiolitis, primarily in children under 2 years of age. PIV serotypes 1 and 2 cause epidemics of croup in the fall months. Infections with PIV serotype 3 can occur in an endemic pattern throughout the year, or may occur as outbreaks, usually in the fall or spring. Croup and bronchiolitis are the most common syndromes of PIV-3 LRI. Infection with these viruses induces short-lived partial resistance to reinfection, but the human host remains susceptible to reinfection with these agents throughout life. While antibody in respiratory secretions is related most directly to resistance to reinfection, cell-mediated immune responses are crucial for limitation and termination of established infection. Current research efforts are directed at more thorough characterization of the developing host immune response to individual viral antigens, and to development of methods for immunization using specific virion peptides. Recently, antiviral therapy has become available for serious RSV infection in young infants.

Differential immunoglobulin G subclass antibody titers to respiratory syncytial virus F and G glycoproteins in adults

Two respiratory syncytial virus glycoproteins, F and G, which differ substantially in the amount of glycosylation were used as antigens in an enzyme-linked immunosorbent assay to determine immunoglobulin G (IgG) subclass titers in 30 experimentally infected healthy adults. The titers of antibodies to the F glycoprotein achieved in postinfection sera were highest in the IgG1 subclass, whereas those to the G glycoprotein were highest and comparable in the IgG1 and IgG2 subclasses. The high IgG2 response to the G glycoprotein suggests that it is seen by the immune system as a polysaccharide antigen, a hypothesis consistent with its large carbohydrate content.

Otitis media in early childhood and its relationship to later verbal and academic performance

The relationship between the occurrence of otitis media with effusion during the first 3 years of life and subsequent verbal and academic performance was examined in 61 socioeconomically disadvantaged children who attended a research day-care program. Study children were participants in a longitudinal study of child development in which the number of episodes of otitis media and duration of each otitis episode were reported prospectively from infancy. The incidence of otitis media was highest during the first 2 years of life. Bilateral otitis media accounted for 66% of the days with otitis media with effusion. Standardized tests of intelligence and academic performance were administered to the children when they were 3 1/2 to 6 years of age. No evidence of associations between measures of early childhood otitis media experience and these measures of verbal or academic functioning was found in this study population.

Otitis media among children in day care: epidemiology and pathogenesis

Acute and persistent middle-ear effusions are the most common complications of upper respiratory illness in young children. Knowledge of the impact of day care attendance on the incidence and prevalence of these conditions is not as complete as is desirable. Several studies suggest that the incidence of acute otitis media may be higher in children who attend group and home day care, but from these studies it is difficult to assess the magnitude of the risk of otitis media related to day care attendance. Research by Danish investigators indicates that the point prevalence of middle-ear effusion may be two to four times higher in children younger than four years old attending group day care centers than in children cared for at home or in smaller home day care settings. Recent epidemiologic and laboratory investigations have begun to elucidate the role of viral infections and of virus-bacteria interaction in the pathogenesis of acute middle-ear effusion. A thorough understanding of the relationship between day care attendance and the occurrence of otitis media with effusion would require studies that quantify the differential risk of disease in different care settings and that relate illness risk to the epidemiology of both viral and bacterial infections of the upper respiratory tract in the different environments. This type of research has not yet been conducted.

Acute respiratory infections in day care

A 16-year, longitudinal study of acute respiratory infections was conducted in a day care center. The incidence of infections peaked in the second six months of life (10 per child per year) and declined thereafter. Fewer than 10% of infections involved the lower respiratory tract. The isolation of respiratory viruses was associated closely with illnesses, and viruses appeared to be the most important causes of respiratory infections. Haemophilus influenzae type b was isolated infrequently and caused no invasive disease. Nontypable H. influenzae and Streptococcus pneumoniae were isolated frequently but were not associated epidemiologically with illnesses. Group A streptococci were isolated with moderate frequency but were not a major problem. Although the data presented are an inadequate basis for firm conclusions, they suggest that the incidence of acute respiratory infections during the first year of life is higher among children in day care centers than among those cared for at home but that the incidence in later years is perhaps lower for children who enter day care as infants and remain in day care through the preschool years.

Ozone effects on alpha-1-proteinase inhibitor in vivo: blood plasma inhibitory activity is unchanged

The possible oxidative inactivation of human blood plasma alpha-1-proteinase inhibitor (alpha-1-PI) by inhaled ozone was assessed. Eleven male volunteers (non-smokers) were exposed to 0.5 ppm ozone for four hours on two consecutive days and ten control subjects were exposed to air under the same conditions. Blood plasma samples, drawn before and after treatment, were assayed for total alpha-1-PI, total protein and elastase inhibitory activity. The amount of active alpha-1-PI in plasma samples was quantitated by titrating porcine pancreatic elastase with increasing amounts of plasma. The importance of constructing titration curves for determinations of this type was demonstrated. No differences were noted in the ratios of total alpha-1-PI/total protein or elastase inhibitory activity/total alpha-1-PI in the plasma from ozone exposed individuals relative to controls. Although inhaled ozone did not result in any significant decrease in the activity of blood plasma alpha-1-PI, these findings do not preclude the possibility of oxidative inactivation of a alpha-1-PI in the lung.

Croup: an 11-year study in a pediatric practice

The etiology and epidemiology of croup were studied in a pediatric group practice over an 11-year period, 1964 to 1975. Croup was diagnosed in 951 instances in 6,165 cases of lower respiratory tract infection (LRI) studied. As census figures of the practice clientele were available, attack rates were calculated. The incidence of total LRI was highest in the first year of life. In contrast, the attack rate for croup was highest in the second year of life; the rate declined gradually after that age. Croup was not diagnosed in the first month of life. Boys were 1.43 times more likely to develop croup than were girls. Three hundred sixty agents were isolated from the 951 croup cases. The parainfluenza viruses accounted for 74.2% of all isolates; 65% of the parainfluenza isolates were classified as parainfluenza virus type 1. Respiratory syncytial virus, influenza viruses A and B, and Mycoplasma pneumoniae were the only other agents isolated in appreciable numbers. The propensity of various agents to produce croup symptoms in children with LRI due to specific microorganisms was 58% for parainfluenzae type 1,60% for parainfluenzae type 2, and 29% for parainfluenzae type 3; similar figures for the other agents varied from 5% to 16%. The role of the various agents in the etiology of croup varied with patient age and depended on the propensity of the agent to produce the croup syndrome and the frequency of isolation of the agent at that age. The parainfluenza viruses were the most important croup agents at all ages; respiratory syncytial virus caused croup in children less than 5 years of age whereas the influenza viruses and M pneumoniae were significant causes of croup only in children more than 5 to 6 years old. Croup occurred predominately in late fall and early winter, times when the parainfluenza viruses, especially type 1, occurred most frequently. The epidemiology of croup differs from that of bronchiolitis, pneumonia, and tracheobronchitis; knowledge of this should be helpful to the clinician caring for children with LRI.

Demonstration of abnormalities in expression of thymic epithelial surface antigens in severe cellular immunodeficiency diseases

Thymic epithelium from three patients with severe cellular immunodeficiency diseases were compared with age-matched normal thymic epithelium using three markers of human thymic epithelium and antibodies against thymosin alpha 1, thymopoietin, and thymosin beta 4. We have previously shown that normal thymic epithelium reacts with antibodies against GQ gangliosides (antibody A2B5) and binds tetanus toxin (TT). In addition, some areas of normal thymic epithelium express human Thy-1 antigen. We found thymic epithelium in patients with severe cellular immunodeficiency diseases to be different from normal subjects. Two children with severe combined immunodeficiency disease (SCID) had thymic epithelium that bound anti-GQ ganglioside antibody but, unlike in normals, did not bind TT. The patient with severe cellular immunodeficiency and normal serum immunoglobulins (Nezelof syndrome) had thymic epithelium that bound TT but, unlike normal thymic epithelium, did not react with anti-GQ ganglioside antibody. Thymic epithelium from both SCID and Nezelof syndrome patients contained thymosin alpha 1, thymopoietin, and thymosin beta 4 and expressed human Thy-1 antigen. In contrast to SCID thymus rudiments, Nezelof thymus contained numerous (though fewer than normal) lymphocytes with mature T cell surface antigens. Thus, using these probes of human thymic epithelium, we have demonstrated heterogeneous defects in thymic epithelial surface marker expression in severe primary cellular immunodeficiency diseases. These defects presumably reflect abnormalities of in vivo thymic epithelial maturation.

Demonstration of abnormalities in expression of thymic epithelial surface antigens in severe cellular immunodeficiency diseases

Thymic epithelium from three patients with severe cellular immunodeficiency diseases were compared with age-matched normal thymic epithelium using three markers of human thymic epithelium and antibodies against thymosin alpha 1, thymopoietin, and thymosin beta 4. We have previously shown that normal thymic epithelium reacts with antibodies against GQ gangliosides (antibody A2B5) and binds tetanus toxin (TT). In addition, some areas of normal thymic epithelium express human Thy-1 antigen. We found thymic epithelium in patients with severe cellular immunodeficiency diseases to be different from normal subjects. Two children with severe combined immunodeficiency disease (SCID) had thymic epithelium that bound anti-GQ ganglioside antibody but, unlike in normals, did not bind TT. The patient with severe cellular immunodeficiency and normal serum immunoglobulins (Nezelof syndrome) had thymic epithelium that bound TT but, unlike normal thymic epithelium, did not react with anti-GQ ganglioside antibody. Thymic epithelium from both SCID and Nezelof syndrome patients contained thymosin alpha 1, thymopoietin, and thymosin beta 4 and expressed human Thy-1 antigen. In contrast to SCID thymus rudiments, Nezelof thymus contained numerous (though fewer than normal) lymphocytes with mature T cell surface antigens. Thus, using these probes of human thymic epithelium, we have demonstrated heterogeneous defects in thymic epithelial surface marker expression in severe primary cellular immunodeficiency diseases. These defects presumably reflect abnormalities of in vivo thymic epithelial maturation.

A longitudinal study of respiratory viruses and bacteria in the etiology of acute otitis media with effusion

We analyzed data from a 14-year longitudinal study of respiratory infections in young children to determine the relative importance of viral respiratory infection and nasopharyngeal colonization with Streptococcus pneumoniae and Haemophilus influenzae as factors influencing the occurrence of acute otitis media with effusion. The incidence of this disorder was increased in children with viral respiratory infections (average relative risk, 3.2; P less than 0.0001). Infection with respiratory syncytial virus, influenza virus (type A or B), and adenovirus conferred a greater risk of otitis media than did infection with parainfluenza virus, enterovirus, or rhinovirus. Colonization of the nasopharynx with Str. pneumoniae or H. influenzae had a lesser effect on the incidence of the disease (average relative risk; 1.5; P less than 0.01). Infections with the viruses more closely associated with acute otitis media (respiratory syncytial virus, adenovirus, and influenza A or B) were correlated with an increased risk of recurrent disease. Prevention of selected otitis-associated viral infections should reduce the incidence of this disease.

The epidemiology of tracheobronchitis in pediatric practice

Epidemiologic characteristics of childhood tracheobronchitis occurring over a 104-month period in Chapel Hill, NC, were ascertained and compared to those of other pediatric lower respiratory illness (LRI) syndromes. Tracheobronchitis accounted for 40% of all LRI seen at the community's only pediatric practice. Tracheobronchitis incidence was highest during the first two years of life, through the ratio of tracheobronchitis incidence to total LRI incidence increased with age. A viral pathogen or Mycoplasma pneumoniae was isolated from 23% of tracheobronchitis cases; the agents most commonly isolated were parainfluenza viruses, influenza viruses, respiratory syncytial virus, and M. pneumoniae. Influenza virus, particularly type B, was isolated more commonly in tracheobronchitis than in other LRI syndromes. Over all age groups, peak incidence of tracheobronchitis, like that of pneumonia and bronchiolitis, occurred during the winter months. In school-age children, however, tracheobronchitis incidence was more likely than that of other syndromes to be elevated in late winter or early spring, when several influenza B outbreaks occurred in Chapel Hill. Available evidence suggests that risk of chronic respiratory disease is related inversely to age at which acute respiratory infection first occurs, and that a component of wheezing may not be required to confer such risk. These considerations, coupled with the high incidence of tracheobronchitis early in life, warrant further description of this syndrome and assessment of its implications.

Actinomycosis. A cause of pulmonary and mediastinal mass lesions in children

Two patients with intrathoracic actinomycosis were examined. One child was asymptomatic and had a slowly expanding lesion in the left upper lobe. The other child had a chronic illness with back pain, weight loss, amenorrhea, and a posterior mediastinal mass. Establishing the cause of these lesions and making the distinction between a neoplastic process and infection were particularly difficult in both cases. Intrathoracic actinomycosis should be considered in the differential diagnosis of pulmonary and mediastinal mass lesions.

Pneumonia: an eleven-year study in a pediatric practice

Data from an 11-year study of acute lower respiratory tract illness were analyzed to provide added insight into the causes and patterns of occurrence of pneumonia in an outpatient pediatric population. Over 80% of all episodes of pneumonia occurred in children less than seven years of age; the peak attack rate was observed in 2-4-year-old children. A virus or Mycoplasma pneumoniae was isolated from 24% of children with pneumonia; 57% of all episodes occurred during outbreaks for which a viral or mycoplasmal cause could usually be identified. Respiratory syncytial virus (RSV), parainfluenza viruses types 1 and 3, adenoviruses, influenza A viruses and M. pneumoniae accounted for 86% of all isolates. Attack rates of pneumonia in preschool children were highest during periods of RSV and influenza A virus prevalence; M. pneumoniae was the most frequent isolate from school aged children. The data contained in this report augment the understanding of the causes of pneumonia in children and provide a data base for scientists interested in the prevention of lower respiratory tract illness in children.

Serum IgE levels and the clinical expression of respiratory illnesses

The incidence, clinical manifestations, and infectious etiology of respiratory illnesses observed in a prospective longitudinal study were correlated with serum IgE values, which were used as objective markers of atopy. The incidence of wheezing illnesses was greater in children with elevated IgE levels, confirming an association previously reported. In contrast, the incidence of upper respiratory illness or middle ear disease showed no correlation with IgE values. The number and types of viral infections distributed evenly throughout the population. The results suggest that children with recurrent URI or MED deserve evaluation for allergy only if there are other clinical findings suggestive of atopy.

Effect of upper respiratory tract infection on eustachian tube ventilatory function in the preschool child

A prospective tympanometric and microbiologic study of 28 pre-schoolchildren was undertaken to better define the effect of acute URI on induction of eustachian tube dysfunction. Significant negative middle ear pressure was present in 12.7% of tympanograms from well children. However, abnormal tympanograms were detected during 74.7% of acute URIs. The abnormality was present on day 1 or 2 of illness in the majority of cases; 10.1% of illnesses were complicated by OME. Respiratory viruses or Sp were etiologically implicated in 40.5% of illnesses; isolation rates of Pn and HF from well and ill children were similar. Although colonization of the nasopharynx of well children with Pn or HF was associated with a higher incidence of abnormal middle ear pressure, colonization with Pn or HF during URI did not influence the frequency of tympanogram abnormality.

The longitudinal approach to the pathogenesis of respiratory disease

Longitudinal observations were made of a well-defined population of children at a day care center in an investigation of the pathogenesis of infections due to respiratory syncytial virus (RSV) and Mycoplasma pneumoniae. A single RSV infection induced a modest but significant degree of resistance to further RSV infection in these children. Age and immunity seemed to interact to decrease the intensity of the clinical expression of illness associated with RSV infection. Infants and young children had asymptomatic or mild infections with M. pneumoniae; some of these children also became reinfected. A rise in titer of antibody to M. pneumoniae was demonstrated frequently in children of all ages. However, stimulation of peripheral lymphocytes by M. pneumoniae antigen was demonstrated infrequently in children younger than four years of age but frequently in children older than four years of age. It is speculated that the clinical expression of disease due to M. pneumoniae is modulated by immune responses; this hypothesis would explain the greater severity of illness in older children and young adults than in younger children. It is also speculated that RSV vaccines will not prevent RSV infection but may be expected to lessen the severity of clinical disease that follows such infections. M. pneumoniae vaccines probably should not be used in children because these vaccines may enhance immunity and increase the sevrity of illness.

The etiologic and epidemiologic spectrum of bronchiolitis in pediatric practice

To develop a broad understanding of the causes and patterns of occurrence of wheezing associated respiratory infections, we analyzed data from an 11-year study of acute lower respiratory illness in a pediatric practice. Although half of the WARI occurred in children less than 2 years of age, wheezing continued to be observed in 19% of children greater than 9 years of age who had lower respiratory illness. Males experienced LRI 1.25 times more often than did females; the relative risk of males for WARI was 1.35. A nonbacterial pathogen was recovered from 21% of patients with WARI; respiratory syncytial virus, parainfluenza virus types 1 and 3, adenoviruses, and Mycoplasma pneumoniae accounted for 81% of the isolates. Patient age influenced the pattern of recovery of these agents. The most common cause of WARI in children under 5 years of age was RSV whereas Mycoplasma pneumoniae was the most frequent isolate from school age children with wheezing illness. The data expand our understanding of the causes of WARI and are useful to diagnosticians and to researchers interested in the control of lower respiratory disease.

Pulmonary cell-mediated cytotoxicity in hamsters with parainfluenza virus type 3 pneumonia

A 51Cr-release cytotoxic assay in vitro was developed to permit definition of the role of local pulmonary cell-mediated immunity in the recovery phase of experimental parainfluenza virus type 3 pneumonia in the Syrian hamster. Cytotoxic effector cells were obtained by bronchalveolar lavage; virus-infected targets were syngeneic secondary hamster kidney cells. Maximal target-cell killing was mediated by lung lavage cells obtained one week after infection; the response waned rapidly thereafter. There was a close temporal correlation between the cytotoxic response and termination of virus replication in the lung. Cytotoxicity was virus specific and was restricted by a requirement for species identity between effector and target cells. Immune spleen cells mediated one-fourth the amount of 51Cr release effected by lung lavage cells, which suggests that cytotoxic effectors were concentrated in the lung. Although the identity of the cytotoxic effector cell was not established conclusively, the characteristics of the response suggested strongly that thymus-derived lymphocytes mediated lysis of target cells. Further work is required to determine the relative importance of this aspect of the host response during recovery from respiratory viral infection.