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PubMedDate not supplied

[Opportunistic microorganisms in respiratory tract diseases in patients of the Moscow Province region].

The respiratory tract microflora in patients with inflammatory processes of the upper and lower respiratory tracts in the Moscow Province region has been studied. Changes in the microflora were found to occur in patients with pyoinflammatory diseases (PID) of the upper and lower respiratory tracts have been found to occur. Gram-positive cocci, mainly staphylococci and streptococci, were shown to play the leading etiological role in the development of PID. As revealed in this study, the microorganisms detected in the inflammations of the upper and lower respiratory tracts are coagulase-negative staphylococci, mainly S. epidermidis, as well as enterococci and streptococci belonging to the group viridans.

Bacteria↗
PubMedDate not supplied

Upper respiratory tract is the major site of antibody production in mycoplasmal induced chronic respiratory disease.

Chronic respiratory disease in rats, resulting from Mycoplasma pulmonis infection, provides a unique opportunity to study the interactions between systemic and mucosal immune systems in a naturally occurring infection of the respiratory tract. In the present studies, an ELISPOT assay specific for the determination of numbers of anti-M, pulmonis antibody forming cells (AFC) was developed. Using this assay, the numbers of IgG, IgM, and IgA AFC in respiratory and nonrespiratory associated lymphoid tissues were determined. The lymphoid tissues associated with the upper respiratory tract, which includes nasal passages and lymph nodes which drain various portions of the upper respiratory tract, were the major site of antibody production. Antibody responses within the lung were minimal. IgM and IgA were the major antibody isotypes produced in each of the tissues examined.

Animals↗
PubMed2006

Impact of human metapneumovirus and human cytomegalovirus versus other respiratory viruses on the lower respiratory tract infections of lung transplant recipients.

UNLABELLED: Viral respiratory tract infections in lung transplant recipients may be severe. During three consecutive winter-spring seasons, 49 symptomatic lung transplant recipients with suspected respiratory viral infection, and 26 asymptomatic patients were investigated for presence of respiratory viruses either in 56 nasopharyngeal aspirate or 72 bronchoalveolar lavage samples taken at different times after transplantation. On the whole, 1 asymptomatic (3.4%) and 28 symptomatic (57.1%) patients were positive for human metapneumovirus (hMPV, 4 patients), influenza virus A (3 patients), and B (2 patients), respiratory syncytial virus (2 patients), human coronavirus (2 patients), human parainfluenza virus (2 patients), rhinovirus (5 patients), while 4 patients were coinfected by 2 respiratory viruses, and 5 were infected sequentially by 2 or more respiratory viruses. In bronchoalveolar lavage samples, hMPV predominated by far over the other viruses, being responsible for 60% of positive specimens, whereas other viruses were present in nasopharyngeal aspirates at a comparable rate. RT-PCR (detecting 43 positive samples/128 examined) was largely superior to monoclonal antibodies (detecting 17 positive samples only). In addition, HCMV was detected in association with a respiratory virus in 4/18 HCMV-positive patients, and was found at a high concentration (>10(5) DNA copies/ml) in 3/16 (18.7%) patients with HCMV-positive bronchoalveolar lavage samples and pneumonia. Coinfections and sequential infections by HCMV and respiratory viruses were significantly more frequent in patients with acute rejection and steroid treatment. IN CONCLUSION: (i) about 50% of respiratory tract infections of lung transplant recipients were associated with one or more respiratory viruses; (ii) hMPV largely predominates in bronchoalveolar lavage of symptomatic lung transplant recipients, thus suggesting a causative role in lower respiratory tract infections; (iii) RT-PCR appears to be the method of choice for detection of respiratory viruses in lung transplant recipients, (iv) a high HCMV load in bronchoalveolar lavage is a risk factor for viral pneumonia, suggesting some measure of intervention for the control of viral infection.

Adult↗
PubMed1998

Respiratory tract infections in Greenlandic children: a prospective cohort study.

Respiratory tract infections in children, measured in terms of both morbidity and mortality, represent a major health problem in Greenland. In particular, otitis media is highly prevalent, and is characterized by early onset and a high degree of chronicity. There is, however, little knowledge about the epidemiology of respiratory tract infections in Greenland. In the spring of 1996, a prospective study of such infections in infants and children was initiated in Sisimiut, West Greenland. The main objectives of the study are to describe the epidemiology of respiratory tract infections in children under four years of age, to estimate the impact of these diseases on short- and long-term morbidity, and to identify risk factors for transmission and clinical severity. An open cohort of children in Sisimiut will be formed, including all resident children below three years of age at the beginning of the study, as well as all children born in the following two-year period: in total approximately 600 children. During two years, these children will be followed closely, including registration of episodes of respiratory tract infections. Furthermore, growth will be measured and microbiological samples obtained.

Child, Preschool↗
PubMed1994

Proteins found within porcine respiratory tract secretions bind lipopolysaccharides of Actinobacillus pleuropneumoniae.

Affinity for porcine respiratory tract secretions was found in some isolates of Actinobacillus pleuropneumoniae and involved lipopolysaccharides (LPS) (M. Bélanger, S. Rioux, B. Foiry, and M. Jacques, FEMS Microbiol. Lett. 97:119-126, 1992). In the present study, the affinity for a crude preparation of porcine respiratory tract mucus of isolates of the Pasteurellaceae family, i.e., Actinobacillus, Haemophilus, and Pasteurella spp., and of some unrelated gram-negative bacteria was examined. Affinity for crude porcine respiratory tract mucus was not a property shared by all Pasteurellaceae isolates tested. Furthermore, affinity for the porcine crude mucus preparation was not unique to the Pasteurellaceae group and did not seem to be restricted to bacteria originating from pigs. Different surface properties of A. pleuropneumoniae isolates in relation to their adherence to crude mucus were examined. The capsular layer seemed to mask the adhesin and interfered with adherence to crude mucus. Two poorly capsulated isolates, which had a more hydrophobic surface and bound Congo red, were also heavily labeled by gold particles coated with polymyxin, which is known to interact with the lipid A-core region of LPS, and adhered strongly to respiratory tract secretions. Tetramethylurea, charged polymers, divalent cations, chelators, monosaccharides and amino sugars, or lectins were unable to inhibit adherence of A. pleuropneumoniae to the crude mucus preparation. To identify the receptor(s) recognized by the lipopolysaccharidic adhesin of A. pleuropneumoniae, affinity chromatography was used. Two bands, which were proteinaceous in nature, of 10 and 11 kDa were recovered. Our results suggest that two low-molecular-mass proteins present in porcine respiratory tract secretions bind A. pleuropneumoniae LPS.

Actinobacillus pleuropneumoniae↗
PubMed2005

Information leaflet and antibiotic prescribing strategies for acute lower respiratory tract infection: a randomized controlled trial.

CONTEXT: Acute lower respiratory tract infection is the most common condition treated in primary care. Many physicians still prescribe antibiotics; however, systematic reviews of the use of antibiotics are small and have diverse conclusions. OBJECTIVE: To estimate the effectiveness of 3 prescribing strategies and an information leaflet for acute lower respiratory tract infection. DESIGN, SETTING, AND PATIENTS: A randomized controlled trial conducted from August 18, 1998, to July 30, 2003, of 807 patients presenting in a primary care setting with acute uncomplicated lower respiratory tract infection. Patients were assigned to 1 of 6 groups by a factorial design: leaflet or no leaflet and 1 of 3 antibiotic groups (immediate antibiotics, no offer of antibiotics, and delayed antibiotics). INTERVENTION: Three strategies, immediate antibiotics (n = 262), a delayed antibiotic prescription (n = 272), and no offer of antibiotics (n = 273), were prescribed. Approximately half of each group received an information leaflet (129 for immediate antibiotics, 136 for delayed antibiotic prescription, and 140 for no antibiotics). MAIN OUTCOME MEASURES: Symptom duration and severity. RESULTS: A total of 562 patients (70%) returned complete diaries and 78 (10%) provided information about both symptom duration and severity. Cough rated at least "a slight problem" lasted a mean of 11.7 days (25% of patients had a cough lasting > or =17 days). An information leaflet had no effect on the main outcomes. Compared with no offer of antibiotics, other strategies did not alter cough duration (delayed, 0.75 days; 95% confidence intervals [CI], -0.37 to 1.88; immediate, 0.11 days; 95% CI, -1.01 to 1.24) or other primary outcomes. Compared with the immediate antibiotic group, slightly fewer patients in the delayed and control groups used antibiotics (96%, 20%, and 16%, respectively; P<.001), fewer patients were "very satisfied" (86%, 77%, and 72%, respectively; P = .005), and fewer patients believed in the effectiveness of antibiotics (75%, 40%, and 47%, respectively; P<.001). There were lower reattendances within a month with antibiotics (mean attendances for no antibiotics, 0.19; delayed, 0.12; and immediate, 0.11; P = .04) and higher attendance with a leaflet (mean attendances for no leaflet, 0.11; and leaflet, 0.17; P = .02). CONCLUSION: No offer or a delayed offer of antibiotics for acute uncomplicated lower respiratory tract infection is acceptable, associated with little difference in symptom resolution, and is likely to considerably reduce antibiotic use and beliefs in the effectiveness of antibiotics.

Acute Disease↗
PubMed1988

Roentgenographic features of common pediatric viral respiratory tract infections.

Viral infections of the respiratory tract in infants and children are common. Little has been reported on roentgenographic findings associated with infection caused by common viruses other than with respiratory syncytial virus. We studied chest roentgenograms from 128 previously healthy infants and children who were infected with respiratory syncytial virus, parainfluenza virus, influenza virus, or adenovirus. Four common roentgenographic findings were detected: parahilar peribronchial infiltrates, hyperexpansion, segmental or lobar atelectasis, and hilar adenopathy. Diffuse interstitial infiltrates and significant pleural fluid accumulations rarely occurred in our series. We confirmed the popular but not well-documented belief that other common respiratory viruses can be associated with roentgenographic findings similar to those caused by respiratory syncytial virus. However, respiratory syncytial virus infection is associated with more abnormal chest roentgenograms than any of the other viruses regardless of the clinical syndrome. Hilar adenopathy was more common in adenovirus infection. Young infants had significantly more abnormal chest roentgenograms, with more hyperexpansion and parahilar peribronchial infiltration than older children. We also found a significant correlation between lobar atelectasis and severity of the illness. In infants and children with viral infection of the lower respiratory tract, roentgenographic information can be a useful adjunct to clinical viral diagnosis.

Adenoviridae Infections↗
PubMed2003

Desire for antibiotics and antibiotic prescribing for adults with upper respiratory tract infections.

OBJECTIVE: Prior studies have shown that 60% to 75% of adults with upper respiratory tract infections want antibiotics. More recent research indicates declines in antibiotic prescribing for upper respiratory tract infections. To investigate whether there has been a comparable decrease in patients' desire for antibiotics, we measured the proportion of adults with upper respiratory tract infections who wanted antibiotics in the winter of 2001-2002. We also sought to identify factors independently associated with wanting antibiotics and antibiotic prescribing. DESIGN: Prospective survey of adults with upper respiratory tract infections prior to visiting an acute care clinic from November 2001 to February 2002. MEASUREMENTS AND MAIN RESULTS: Thirty-nine percent of 310 patients wanted antibiotics. Many patients wanted relief from symptoms (43%) or pain (24%) and many patients expected to receive a diagnosis (49%) or reassurance during the visit (13%). In multivariable modeling, independent predictors of wanting antibiotics were prior antibiotic use (odds ratio [OR], 2.4; 95% confidence interval [CI], 1.3 to 4.7) and current smoking (OR, 3.1; 95% CI, 1.3 to 7.3). Physicians prescribed antibiotics to 46% of patients who wanted antibiotics and 29% of patients who did not want antibiotics (P=.01). In multivariable modeling, wanting antibiotics was an independent predictor of antibiotic prescribing (OR, 2.1; 95% CI, 1.1 to 4.4). CONCLUSIONS: Only 39% of adults seeking care for upper respiratory tract infections wanted antibiotics, less than in previous studies. In continuing efforts to break the cycle of inappropriate antibiotic use, physicians should not assume that most patients with upper respiratory tract infections want antibiotics.

Acute Disease↗
PubMed1988

Day-care center attendance and hospitalization for lower respiratory tract illness.

To identify risk factors associated with hospitalization for acute lower respiratory tract illness, 102 children less than 2 years of age admitted to four Atlanta metropolitan area hospitals between December 1984 and June 1985 with the diagnosis of lower respiratory tract illness were studied. The most common causative agent associated with illness was respiratory syncytial virus, followed by other respiratory viruses, Haemophilus influenzae, and Streptococcus pneumoniae. The 102 case-patients were compared with 199 age- and sex-matched controls. A parent or guardian for each patient and control was interviewed by telephone regarding demographic data, care outside the home, breast-feeding, previous medical history, allergies, and smoking and illness in household members. Five factors were associated with lower respiratory tract illness in both a univariate analysis and a multiple logistic regression model (P less than .05). These factors were the number of people sleeping in the same room with the child, a lack of immunization the month before the patient was hospitalized, prematurity, a history of allergy, and regular attendance in a day-care center (more than six children in attendance). Care received outside of the home in a day-care home (less than or equal to six children in attendance) was not associated with lower respiratory tract illness. The suggestion made by our study and other studies was that for children less than 2 years of age, care outside of the home is an important risk factor for acquiring lower respiratory tract illness, as well as other infectious diseases, and that this risk can be reduced by using a day-care home instead of a day-care center.

Breast Feeding↗
PubMed2003

Herpes simplex virus in the respiratory tract of critical care patients: a prospective study.

BACKGROUND: Herpes simplex virus (HSV) is occasionally detected in the lower respiratory tract of patients in intensive care, but its clinical importance in such situations remains unclear. We did a prospective cohort study to define the prevalence, origin, risk factors, and clinical relevance of HSV in the respiratory tract of patients undergoing critical care. METHODS: We tested 764 patients admitted to intensive care for the presence of HSV in the respiratory tract, and assessed statistical relations between this virus and clinical variables. FINDINGS: HSV was detected by oropharyngeal swab in the upper respiratory tract of 169 (22%) of 764 patients, within 10 days of admission for 150 (89%) of these individuals. The virus was isolated in 58 (16%) of 361 patients whose lower respiratory tract was sampled. The presence of HSV in the throat was a risk factor for development of HSV infections in the lower respiratory tract (p<0.001). HSV was isolated most frequently in patients with severe disease. HSV in the throat was associated with acute respiratory distress syndrome (p<0.001) and with increased length of stay in intensive care (p<0.001). INTERPRETATION: Our data suggest that HSV reactivation or infection of the upper respiratory tract is frequent among patients in intensive care, and is a risk factor for development of lower respiratory tract infection with this virus, possibly by means of aspiration.

Adolescent↗
PubMed1993

Cefpirome: efficacy in the treatment of urinary and respiratory tract infections and safety profile.

The efficacy and safety of cefpirome was reviewed from the documentation of comparative pivotal trials in patients with urinary tract or lower respiratory tract infections UTIs and LRTIs, respectively). A majority of patients with UTIs had pyelonephritis and/or complicated UTIs. Most patients with LRTIs had community acquired pneumonia. Studies of UTI included 865 patients treated with cefpirome 1 g bid and 443 patients allocated to ceftazidime 1 g bid. Satisfactory clinical outcome was reported in 87% and 83%, respectively. Eradication of organisms causing bacteriuria was achieved in 87% and 86%, respectively. In the LRTI trials 199 patients received cefpirome 1 g bid and in 653 patients it was dosed 2 g bid. Comparators were ceftazidime 2 g bid (N = 197) or 2 g tid (N = 296) or ceftriaxone 1 g bid (N = 77). With all treatments unsatisfactory clinical or bacteriological outcome was recorded in < 15% of the patients. The safety of cefpirome and comparators was evaluated in pivotal phase II and III studies and deaths were analysed in all clinical trials for which data were available by June 30th 1991. Cefpirome did not differ from comparators in terms of frequencies or distribution within body systems of adverse events. Death rates were 3.9% in 9189 patients receiving cefpirome and 5.1% in 3162 receiving a comparator. The deaths were in an absolute majority of cases not considered related to study drug given. The most common cause of death was infection, indicating that the trial samples were selected from populations of patients with serious infections. Cefpirome was as safe and efficaceous as its comparators and is a new injectable cephalosporin with broader spectrum than ceftazidime. It should be a suitable alternative for empiric treatment of serious infections in hospitalised patients.

Adolescent↗
PubMed2005

Sarcoidosis with upper respiratory tract involvement.

The aim of the study was to investigate the upper respiratory tract as a site of extrapulmonary sarcoidosis. Diagnosis of sarcoidosis with upper respiratory tract involvement was performed on the basis of clinical, laboratory, radiographic and histological evidence and by excluding other granulomatous diseases in eight patients followed by the Sarcoidosis Regional Reference Centre pneumologists in collaboration with an experienced ENT specialist at Siena University. In five cases, sarcoidosis was localized in the parotid glands, in the other three subjects larynx, nasopharynx and nose were involved. In four patients parotid gland, nasopharynx and upper respiratory tract mucous membrane involvement was the only clinical manifestation at onset of the disease. Upper respiratory tract involvement should be suspected in all patients with systemic sarcoidosis and in patients with persistent upper respiratory tract symptoms of unknown cause. What a general practitioner should do as not to miss SURT is underlined. Interdisciplinary management and collaboration are of paramount importance for rapid diagnosis and to avoid the possible complications of this form.

Adult↗
PubMed1998

[Efficacy and tolerance of fenspiride in adult patients with acute respiratory tract infections].

Fenspiride is an antiinflammatory drug targeted for the respiratory tract. In our study clinical efficacy and tolerance of drug were evaluated in 392 adult patients with acute respiratory tract infections. According to clinical criteria all observed symptoms were classified as mild, moderate and severe. The most of observed patients were included into moderate symptom score. Cough and nose obturation were dominant symptoms. All noticed changes in the upper respiratory tract were decreased after fenspiride therapy in 7 days trial. In 168 observed patients systemic and in 60 local acting antibiotics were successfully applied. Excellent tolerance of fenspiride was documented in 59% and good tolerance --in 34% of patients. Observed adverse reactions were classified as mild and in 20 patients fenspiride was rejected. Authors suggest that fenspiride therapy is save and successful in patient with acute respiratory tract infection. Good results in patients with bronchitis in decreasing of bronchospasm indicate fenspiride as a good tool in bronchial infection.

Acute Disease↗
PubMed1990

Epidemiological features and chemotherapy of community-acquired respiratory tract infections.

The epidemiology of community-acquired respiratory tract infections (RTI) is reviewed with emphasis on acute pharyngitis, otitis media, sinusitis, epiglottitis and pneumonia. The numerical importance of upper respiratory tract infections is stressed and their economic impact discussed. Community-acquired pneumonia, although less common, is a more serious infection with a frequent requirement for hospitalization. The heterogeneous microbial aetiology of RTI is stressed, together with the impact this has on chemotherapeutic choice. The latter is likely to remain largely empirical and based on the prevalence of identified pathogens, spectrum of activity and the pharmacokinetic behaviour of the selected agents. The increasing frequency of resistance among respiratory pathogens, notably Haemophilus influenzae, and to a lesser extent Streptococcus pneumoniae, together with the high incidence of beta-lactamase production among Branhamella catarrhalis is of concern. In addition, the issue of beta-lactam inactivation by commensal bacteria suggests that chemotherapeutic strategies for the control of community-acquired respiratory tract infection might justifiably be reconsidered.

Epiglottitis↗
PubMedDate not supplied

Prevalence of Moraxella catarrhalis infections of the lower respiratory tract in elderly patients.

OBJECTIVES: To determine: *rate of isolation of Moraxella catarrhalis in elderly patients having lower respiratory tract infection *The antibiotic susceptibility pattern of Moraxella catarrhalis isolates. *The predisposing factors responsible for Moraxella catarrhalis infections of lower respiratory tract. MATERIAL AND METHOD: This is a prospective study carried out at Manipal Teaching Hospital, Pokhara during May 2002 to April 2003. A total of 716 sputum samples collected from patients with suspected lower respiratory tract infection were investigated. The samples were subjected to Gram stain, culture and sensitivity. Sputum samples were inoculated on blood and chocolate agar and incubated at 37 degrees C for 18 to 24 hours in candle jar containing 3-5% Co2. For the identification of bacterial isolates, the cultural and colonial characteristics were recorded and identified with the use of biochemical test. The susceptibility of bacterial isolates to antimicrobial agent was performed following Kirby-Bauer method. RESULT: Out of the 716 samples, 355 (49.58%) grew normal commensals of the upper respiratory tract. Respiratory pathogens were recovered from 361 (50.41%) samples. The most common respiratory pathogen was H. influenzae (26. 86%), followed by S. pneumoniae (21.16%). Moraxella catarrhalis accounted for 6.90%. Rate of isolation of Moraxella catarrhalis was higher in males than in females. Out of 25 isolates 16 were from males and 9 were from females. Frequency of isolation of Moraxella catarrhalis was more frequently seen in age group 61-70 years. It was most commonly recovered in winter. The most effective antibiotics were amoxicillin-clavulanate and ceftriaxone and least was ampicillin. CONCLUSION: Moraxella catarrhalis isolation from sputum especially in persons above 60 years of age and in the absence of other well established pathogens should not be disregarded as they can cause lower respiratory tract infection in these individuals.

Age Distribution↗
PubMed1997

Upper respiratory tract disease and mycoplasmosis in desert tortoises from Nevada.

A population of desert tortoises (Gopherus agassizii) at Yucca Mountain (Nevada, USA) was monitored during four sampling periods using enzyme-linked immunosorbent assays (ELISA) to determine the percentage of individuals that had been exposed to Mycoplasma agassizii, a causative agent of upper respiratory tract disease. Respiratory tract disease has been considered a significant factor in the decline of desert tortoise populations in the Mojave Desert (USA). Few differences between sexes in ELISA values or percentages testing positive were noted. From 15 to 23% of samples per period tested positive for exposure to the mycoplasma. However, we noted few clinical signs of upper respiratory tract disease. This is in contrast to an earlier study which reported a similar proportion of seropositive tortoises as well as a high percentage of tortoises with clinical signs. However, our results are consistent with that study's conclusion that seropositivity for M. agassizii was a poor predictor of the likelihood to exhibit clinical signs of upper respiratory tract disease. Earlier reported epizootics of mycoplasma-associated respiratory disease occurred mainly during times of drought. Our samples were collected during a period of average to above-average rainfall, suggesting that manifestation of clinical signs of the disease may depend upon the physiological condition of tortoises which, in turn, is related to environmental conditions.

Animals↗
PubMed2006

Candida colonization of the respiratory tract and subsequent pseudomonas ventilator-associated pneumonia.

BACKGROUND: Recovery of Candida from the respiratory tract of a critically ill patient receiving mechanical ventilation (MV) usually indicates colonization rather than infection of the respiratory tract. However, interactions between Candida and bacteria, particularly Pseudomonas, have been reported. Thus, Candida colonization of the respiratory tract may predispose to bacterial ventilator-associated pneumonia (VAP). METHODS: In a multicenter study of immunocompetent critically ill patients receiving MV for > 2 days, we compared the incidence of pneumonia in patients with and without (exposed/unexposed) respiratory-tract Candida colonization, matched on study center, admission year, and MV duration. RESULTS: Over the 4-year study period, of the 803 patients meeting study inclusion criteria in the six study centers, 214 patients (26.6%) had respiratory tract Candida colonization. Candida albicans was the most common species (68.7%), followed by Candida glabrata (20.1%) and Candida tropicalis (13.1%). Extrapulmonary Candida colonization was more common in exposed patients (39.7% vs 8.3%, p = 0.01). Exposed patients had longer ICU and hospital stays but similar mortality to unexposed patients. The matched exposed/unexposed nested cohort study identified bronchial Candida colonization as an independent risk factor for pneumonia (24.1% vs 17.6%; adjusted odds ratio [OR], 1.58; 95% confidence interval [CI], 0.94 to 2.68; p = 0.0860); the risk increase was greatest for Pseudomonas pneumonia (9% vs 4.8%; adjusted OR, 2.22; 95% CI, 1.00 to 4.92; p = 0.049). CONCLUSIONS: Candida colonization of the respiratory tract is common in patients receiving MV for > 2 days and is associated with prolonged ICU and hospital stays, and with an increased risk of Pseudomonas VAP.

Aged↗
PubMed2004

Human metapneumovirus and lower respiratory tract disease in otherwise healthy infants and children.

BACKGROUND: We sought to determine the role of human metapneumovirus in lower respiratory tract illness in previously healthy infants and children. METHODS: We tested nasal-wash specimens, obtained over a 25-year period from otherwise healthy children presenting with acute respiratory tract illness, for human metapneumovirus. RESULTS: A viral cause other than human metapneumovirus was determined for 279 of 687 visits for acute lower respiratory tract illness (41 percent) by 463 children in a population of 2009 infants and children prospectively seen from 1976 to 2001. There were 408 visits for lower respiratory tract illness by 321 children for which no cause was identified. Of these 321 children, specimens from 248 were available. Forty-nine of these 248 specimens (20 percent) contained human metapneumovirus RNA or viable virus. Thus, 20 percent of all previously virus-negative lower respiratory tract illnesses were attributable to human metapneumovirus, which means that 12 percent of all lower respiratory tract illnesses in this cohort were most likely due to this virus. The mean age of human metapneumovirus-infected children was 11.6 months, the male:female ratio was 1.8:1, 78 percent of illnesses occurred between December and April, and the hospitalization rate was 2 percent. The virus was associated with bronchiolitis in 59 percent of cases, pneumonia in 8 percent, croup in 18 percent, and an exacerbation of asthma in 14 percent. We also detected human metapneumovirus in 15 percent of samples from 261 patients with upper respiratory tract infection but in only 1 of 86 samples from asymptomatic children. CONCLUSIONS: Human metapneumovirus infection is a leading cause of respiratory tract infection in the first years of life, with a spectrum of disease similar to that of respiratory syncytial virus.

Adolescent↗