Human T-Lymphotropic Virus type 1c subtype proviral loads, chronic lung disease and survival in a prospective cohort of Indigenous Australians.

BACKGROUND: The Human T-Lymphotropic Virus type 1c subtype (HTLV-1c) is highly endemic to central Australia where the most frequent complication of HTLV-1 infection in Indigenous Australians is bronchiectasis. We carried out a prospective study to quantify the prognosis of HTLV-1c infection and chronic lung disease and the risk of death according to the HTLV-1c proviral load (pVL). METHODOLOGY/PRINCIPAL FINDINGS: 840 Indigenous adults (discharge diagnosis of bronchiectasis, 154) were recruited to a hospital-based prospective cohort. Baseline HTLV-1c pVL were determined and the results of chest computed tomography and clinical details reviewed. The odds of an association between HTLV-1 infection and bronchiectasis or bronchitis/bronchiolitis were calculated, and the impact of HTLV-1c pVL on the risk of death was measured. Radiologically defined bronchiectasis and bronchitis/bronchiolitis were significantly more common among HTLV-1-infected subjects (adjusted odds ratio = 2.9; 95% CI, 2.0, 4.3). Median HTLV-1c pVL for subjects with airways inflammation was 16-fold higher than that of asymptomatic subjects. There were 151 deaths during 2,140 person-years of follow-up (maximum follow-up 8.13 years). Mortality rates were higher among subjects with HTLV-1c pVL ≥1000 copies per 105 peripheral blood leukocytes (log-rank χ2 (2df) = 6.63, p = 0.036) compared to those with lower HTLV-1c pVL or uninfected subjects. Excess mortality was largely due to bronchiectasis-related deaths (adjusted HR 4.31; 95% CI, 1.78, 10.42 versus uninfected). CONCLUSION/SIGNIFICANCE: Higher HTLV-1c pVL was strongly associated with radiologically defined airways inflammation and with death due to complications of bronchiectasis. An increased risk of death due to an HTLV-1 associated inflammatory disease has not been demonstrated previously. Our findings indicate that mortality associated with HTLV-1c infection may be higher than has been previously appreciated. Further prospective studies are needed to determine whether these results can be generalized to other HTLV-1 endemic areas.

Predictors of successful telephone follow-up in a multicenter study of infants with severe bronchiolitis.

PURPOSE: To identify the characteristics that predict successful telephone follow-up with parents of infants with severe bronchiolitis. METHODS: We analyzed data from a 17-center, prospective cohort study of infants (age <1 year) hospitalized with bronchiolitis during three consecutive fall/winter seasons. Participant contact information and clinical data were collected during the index hospitalization. Parents were called at 6-month intervals (based on the child's age) after discharge to assess respiratory problems. The primary outcome was age 12-month telephone interview status. Participants were classified as unreachable after 28 days of unsuccessful attempts. RESULTS: 798 of 916 children (87%) completed the age 12-month telephone interview. In unadjusted analyses, factors associated with successful follow-up included: private health insurance, annual household income $60,000 or more, and residing in the Northeast, Midwest, or West. Follow-up was less common among non-Hispanic blacks, Hispanics, and households with 3 or more children. In multivariable analyses, follow-up was more likely among parents of females, and, compared with the South, in the Northeast and Midwest (all P < .05). Compared with non-Hispanic whites, non-Hispanic blacks and Hispanics remained less likely to complete the interview as did households with 3 or more children (all P < .05). CONCLUSION: Sociodemographic and geographic factors predict successful telephone follow-up, even among parents of infants with severe illness.

Disparities in infant hospitalizations in Indigenous and non-Indigenous populations in Quebec, Canada.

BACKGROUND: Infant mortality is higher in Indigenous than non-Indigenous populations, but comparable data on infant morbidity are lacking in Canada. We evaluated disparities in infant morbidities experienced by Indigenous populations in Canada. METHODS: We used linked population-based birth and health administrative data from Quebec, Canada, to compare hospitalization rates, an indicator of severe morbidity, in First Nations, Inuit and non-Indigenous singleton infants (< 1 year) born between 1996 and 2010. RESULTS: Our cohort included 19 770 First Nations, 3930 Inuit and 225 380 non-Indigenous infants. Compared with non-Indigenous infants, all-cause hospitalization rates were higher in First Nations infants (unadjusted risk ratio [RR] 2.05, 95% confidence interval [CI] 1.99-2.11; fully adjusted RR 1.43, 95% CI 1.37-1.50) and in Inuit infants (unadjusted RR 1.96, 95% CI 1.87-2.05; fully adjusted RR 1.37, 95% CI 1.24-1.52). Higher risks of hospitalization (accounting for multiple comparisons) were observed for First Nations infants in 12 of 16 disease categories and for Inuit infants in 7 of 16 disease categories. Maternal characteristics (age, education, marital status, parity, rural residence and Northern residence) partly explained the risk elevations, but maternal chronic illnesses and gestational complications had negligible influence overall. Acute bronchiolitis (risk difference v. non-Indigenous infants, First Nations 37.0 per 1000, Inuit 39.6 per 1000) and pneumonia (risk difference v. non-Indigenous infants, First Nations 41.2 per 1000, Inuit 61.3 per 1000) were the 2 leading causes of excess hospitalizations in Indigenous infants. INTERPRETATION: First Nations and Inuit infants had substantially elevated burdens of hospitalizations as a result of diseases of multiple systems. The findings identify substantial unmet needs in disease prevention and medical care for Indigenous infants.

Risk factors for adverse outcomes of Indigenous infants hospitalized with bronchiolitis.

BACKGROUND: Hospitalized bronchiolitis imposes a significant burden among infants, particularly among Indigenous children. Traditional or known risk factors for severe disease are well described, but there are limited data on risks for prolonged hospitalization and persistent symptoms. Our aims were to determine factors (clinical and microbiological) associated with (i) prolonged length of stay (LOS); (ii) persistent respiratory symptoms at 3 weeks; (iii) bronchiectasis up to ∼24 months post-hospitalisation; and (iv) risk of respiratory readmissions within 6 months. METHODS: Indigenous infants hospitalized with bronchiolitis were enrolled at Royal Darwin Hospital between 2008 and 2013. Standardized forms were used to record clinical data. A nasopharyngeal swab was collected at enrolment to identify respiratory viruses and bacteria. RESULTS: The median age of 232 infants was 5 months (interquartile range 3-9); 65% male. On multivariate regression, our 12 point severity score (including accessory muscle use) was the only factor associated with prolonged LOS but the effect was modest (+3.0 hr per point, 95%CI: 0.7, 5.1, P = 0.01). Presence of cough at 3 weeks increased the odds of bronchiectasis (OR 3.0, 95%CI: 1.1, 7.0, P = 0.03). Factors associated with respiratory readmissions were: previous respiratory hospitalization (OR 2.3, 95%CI: 1.0, 5.4, P = 0.05) and household smoke (OR 2.6, 95%CI: 1.0, 6.3, P = 0.04). CONCLUSION: Increased severity score is associated with prolonged LOS in Indigenous children hospitalized with bronchiolitis. As persistent symptoms at 3 weeks post-hospitalization are associated with future diagnosis of bronchiectasis, optimising clinical care beyond hospitalization is needed to improve long-term respiratory outcomes for infants at risk of respiratory disease. Pediatr Pulmonol. 2016;51:613-623. © 2015 Wiley Periodicals, Inc.

Racial/ethnic differences in the presentation and management of severe bronchiolitis.

BACKGROUND AND OBJECTIVE: Bronchiolitis is the leading cause of hospitalization for US infants and is associated with increased risk of childhood asthma. Although studies have shown differences in the presentation and management of asthma across race/ethnicity, it is unclear if such differences are present for bronchiolitis. We examined if racial/ethnic differences exist in the presentation and management of severe bronchiolitis. METHODS: We performed a 16-center, prospective cohort study from 2007 to 2010. Children <2 years old hospitalized with a diagnosis of bronchiolitis were included. A structured interview, chart review, and 1-week phone follow-up were completed. Multivariable logistic regression was used to examine the independent association between race/ethnicity and diagnostic imaging, treatment (eg, albuterol, corticosteroids, and continuous positive airway pressure/intubation), management (eg, intensive care unit admission and length of stay), discharge on inhaled corticosteroids, and bronchiolitis relapse. RESULTS: Among 2130 patients, 818 (38%) were non-Hispanic white (NHW), 511 (24%) were non-Hispanic black (NHB), and 801 (38%) were Hispanic. Compared with all groups, NHB children were most likely to receive albuterol before admission (odds ratio [OR]: 1.58; 95% confidence interval [CI]: 1.20-2.07) and least likely to receive chest x-rays during hospitalization (OR: 0.66; 95% CI: 0.49-0.90). Hispanic children were most likely to be discharged on inhaled corticosteroids (OR: 1.92; 95% CI: 1.19-3.10). CONCLUSION: We observed differences between NHW and minority children regarding preadmission albuterol use, inpatient diagnostic imaging, and prescription of inhaled corticosteroids at discharge, practices that deviate from the American Academy of Pediatrics guidelines. The causes of these differences require further study, but they support implementation of care pathways for severe bronchiolitis.

Frequency, duration and predictors of bronchiolitis episodes of care among infants ≥32 weeks gestation in a large integrated healthcare system: a retrospective cohort study.

BACKGROUND: Bronchiolitis is common in the first two years of life and is the most frequent cause of hospitalization in this age group. No previous studies have used an episode-of-care analysis to describe the frequency, duration, and predictors of bronchiolitis episodes of care during the first two years. METHODS: We conducted a retrospective cohort study of 123,264 infants ≥32 weeks gestation born at 6 Northern California Kaiser Permanente hospitals between 1996 and 2002. We used electronic medical records to concatenate hospital, emergency department and outpatient health care encounters for bronchiolitis into discrete episodes of care. We used descriptive statistics to report frequency and duration of bronchiolitis episodes and used logistic regression to assess the effect of gestational age and other clinical and demographic predictors on the outcome of bronchiolitis episodes. RESULTS: Among all infants, the rate of bronchiolitis episodes was 162 per 1000 children during the first 2 years of life; approximately 40% required >1 day of medical attention with a mean duration of 7.0 ± 5.9 days. Prematurity was associated with increased risk of bronchiolitis episodes and longer duration. Bronchiolitis episodes rates per 1000 infants were 246 for 32-33 weeks gestational age, 204 for 34-36 weeks, and 148-178 for >36 weeks. Male gender, African-American and Hispanic race/ethnicity, and parental history of asthma were associated with an increased risk of having a bronchiolitis episode and/or longer duration. CONCLUSIONS: Bronchiolitis episodes of care are frequent during the first two years of life and the duration ranges from 1 to 27 days. Prematurity was associated with more frequent and longer duration of bronchiolitis episodes of care, which may reflect illness severity and/or perceived vulnerability.

Trends in lower respiratory tract infection hospitalizations among American Indian/Alaska Native children and the general US child population.

OBJECTIVE: To describe trends in the rate of hospitalization for lower respiratory tract infection (LRTI) among American Indian/Alaska Native (AI/AN) children and the general US population of children aged <5 years. STUDY DESIGN: This was a retrospective analysis of trends and hospitalization rates for LRTI-associated hospitalizations in 1998-2008 among AI/AN children aged <5 years using the Indian Health Service direct/contract inpatient data, and also among the general population of US children aged <5 years using the Nationwide Inpatient Sample. RESULTS: The 2006-2008 LRTI-associated hospitalization rate for AI/AN children aged <5 years (21.8 per 1000/year) was 32% lower than the 1998-1999 rate, and 1.6-fold higher than the general US children rate (13.8 per 1000/year; 95% CI, 12.8-14.8). Higher rates were seen in AI/AN children aged <5 years in the Alaska and the Southwest regions of the United States (41.2 and 28.0 per 1000/year, respectively). In infants, these rates were 136.4 and 82.4 per 1000/year, respectively, exceeding the rate in the general US infant population (37.1 per 1000/year; 95% CI, 34.3-40.0). The greatest disparity in the LRTI-associated hospitalization rate between AI/AN infants and the general US infant population was seen for pneumonia, with a 3-fold higher rate in AI/AN infants (36.2 per 1000/year vs 12.7 per 1000/year; 95% CI, 11.8-13.6). CONCLUSION: The LRTI-associated hospitalization rate is higher in AI/AN children, particularly infants from Alaska and the American Southwest, compared with the general US child population. Closing this gap will require addressing housing and sanitation inequities and ensuring high immunization rates and access to care.

Differential association between HLA and diffuse panbronchiolitis in Northern and Southern Chinese.

BACKGROUND: Diffuse panbronchiolitis (DPB) is a progressive inflammatory pulmonary disease that predominately affects East Asians. Genetic susceptibility to DPB is correlated with the human leukocyte antigens HLA-B54 in Japanese and HLA-A11 in Koreans. However, no systematic genetic study of DPB pathogenesis has been conducted in the Chinese population. The aim of this study was to investigate the possible association between HLA and disease susceptibility in Chinese patients with DPB. METHODS: A literature review of both Chinese and English language studies on Chinese DPB patients, published between 1983 and 2010, was conducted. Seventy subjects met the inclusion criteria and were retrospectively analyzed for HLA gene frequency according to geographic region. RESULTS: HLA-B54 frequency was significantly greater in DPB patients than in controls in the Northern Chinese group (35.7% vs. 4.6%, p=7.5×10(-7)). Although the HLA-B54 frequency was slightly increased in the Southern Chinese patients, the difference was not significant compared with control subjects (14.3% vs. 5.7%, p=0.28). The HLA-A11 frequency was significantly greater in DPB patients than controls in the Southern Chinese group (54.8% vs. 26.4%, p=0.009). Despite an increase of HLA-A11 frequency in the Northern Chinese group, no significant variation in HLA-A11 frequency was found compared with control subjects (42.9% vs. 30.8%, p=0.535). The HLA-A2 frequency was significantly decreased in DPB patients than in controls in the Southern Chinese group (22.9% vs. 66.0%, p=0.001). However, no significant difference in HLA-A2 frequency was found in the Northern Chinese group (50.0% vs. 46.9%, p=0.872). CONCLUSION: HLA-B54 and HLA-A11 were positively associated with DPB in Northern and Southern Chinese, respectively. Population substructure may impact the genetic predisposition of DPB in China.

Reduction in disparity for pneumonia hospitalisations between Australian Indigenous and non-Indigenous children.

BACKGROUND: In the 1990s pneumonia hospitalisation rates in Western Australia (WA) were 13 times higher in Indigenous children than in non-Indigenous children. Rates of invasive pneumococcal disease in Indigenous children declined following the introduction in 2001 of 7-valent pneumococcal conjugate vaccine (7vPCV) in a 2-4-6 month schedule with an 18-month pneumococcal polysaccharide booster (PPV). We investigated population trends for pneumonia hospitalisations between 1996 and 2005. METHODS: Population-based retrospective data linkage cohort study of singleton live births from 1996-2005. Hospitalisations for acute lower respiratory infections in Indigenous and non-Indigenous children less than 5 years of age were extracted and trends in age-specific incidence rates were examined using log-linear modelling. RESULTS: From 245 249 births (7.1% Indigenous), there were 7727 pneumonia episodes. Between 1996 and 2000 and 2001 and 2005 all-cause pneumonia hospitalisations fell by 28-44% in Indigenous children aged 6-35 months with no equivalent decline in non-Indigenous children or for other acute lower respiratory infections. Incidence rate ratios for pneumonia comparing Indigenous with non-Indigenous children aged 6-11 months fell from 14.6 (95% CI 12.3 to 17.2) in 1996-2000 to 9.9 (8.4 to 11.6) in 2001-2005. Log-linear modelling showed a steady decline in Indigenous children of 9%/annum (5-12%) at age 12-23 months for all-cause pneumonia and 37%/annum (20-50%) at age 6-11 months for pneumococcal pneumonia from 1996 to 2005, including the years prior to introduction of pneumococcal vaccines. CONCLUSIONS: Pneumonia hospitalisations and the disparity between Indigenous and non-Indigenous children has declined by a third. The unique Australian pneumococcal vaccine programme is likely to have had a significant effect but changes in socioeconomic factors have also contributed to the declines.

Effect of azithromycin on patients with diffuse panbronchiolitis: retrospective study of 51 cases.

BACKGROUND: Patients with diffuse panbronchiolitis (DPB) are routinely treated with erythromycin, clarithromycin, and roxithromycin. The clinical effect of azithromycin on DPB has not been confirmed in a large cohort. OBJECTIVE: The present study was undertaken to investigate the clinical effects of azithromycin on patients with DPB. METHODS: Fifty-one patients with DPB treated with azithromycin in Shanghai Pulmonary Hospital, China, from July 2001 to April 2007 were analyzed retrospectively. Azithromycin (500 mg a day) was administrated intravenously in the first 1-2 weeks, taken orally (500 mg, once a day) for 3 months, and tapered to 3 times a week for 6-12 months. The patients were followed up until September 1, 2009. The therapeutic effect, according to their clinical and radiological findings, arterial gas analysis, lung function, and sputum bacterium before and after the therapy, was categorized into the following five grades: 1) cured; 2) improved; 3) no response; 4) aggravation, and 5) relapse. RESULTS: With azithromycin therapy, 14 (27.5%) patients with DPB were completely cured. The symptoms were eliminated to certain degrees for the other 36 cases (70.6%) of DPB. Five-year survival in this cohort was 94.1%. CONCLUSION: Azithromycin is effective and well tolerated for patients with diffuse panbronchiolitis.

Randomized placebo-controlled trial on azithromycin to reduce the morbidity of bronchiolitis in Indigenous Australian infants: rationale and protocol.

BACKGROUND: Acute lower respiratory infections are the commonest cause of morbidity and potentially preventable mortality in Indigenous infants. Infancy is also a critical time for post-natal lung growth and development. Severe or repeated lower airway injury in very young children likely increases the likelihood of chronic pulmonary disorders later in life. Globally, bronchiolitis is the most common form of acute lower respiratory infections during infancy. Compared with non-Indigenous Australian infants, Indigenous infants have greater bacterial density in their upper airways and more severe bronchiolitis episodes. Our study tests the hypothesis that the anti-microbial and anti-inflammatory properties of azithromycin, improve the clinical outcomes of Indigenous Australian infants hospitalised with bronchiolitis. METHODS: We are conducting a dual centre, randomised, double-blind, placebo-controlled, parallel group trial in northern Australia. Indigenous infants (aged ≤ 24-months, expected number = 200) admitted to one of two regional hospitals (Darwin, Northern Territory and Townsville, Queensland) with a clinical diagnosis of bronchiolitis and fulfilling inclusion criteria are randomised (allocation concealed) to either azithromycin (30 mg/kg/dose) or placebo administered once weekly for three doses. Clinical data are recorded twice daily and nasopharyngeal swab are collected at enrollment and at the time of discharge from hospital. Primary outcomes are 'length of oxygen requirement' and 'duration of stay,' the latter based upon being judged as 'ready for respiratory discharge'. The main secondary outcome is readmission for a respiratory illness within 6-months of leaving hospital. Descriptive virological and bacteriological (including development of antibiotic resistance) data from nasopharyngeal samples will also be reported. DISCUSSION: Two published studies, both involving different patient populations and settings, as well as different macrolide antibiotics and treatment duration, have produced conflicting results. Our randomised, placebo-controlled trial of azithromycin in Indigenous infants hospitalised with bronchiolitis is designed to determine whether it can reduce short-term (and potentially long-term) morbidity from respiratory illness in Australian Indigenous infants who are at high risk of developing chronic respiratory illness. If azithromycin is efficacious in reducing the morbidly of Indigenous infants hospitalised with bronchiolitis, the intervention would lead to improved short term (and possibly long term) health benefits.

Idiopathic bronchiolitis with features of diffuse panbronchiolitis in an African-American patient with hepatitis C virus infection.

Diffuse panbronchiolitis (DPB) is an idiopathic inflammatory process involving respiratory bronchioles, largely restricted to Japanese people and associated with HLA Bw54. We report a case of idiopathic bronchiolitis with DPB features in an African American with hepatitis C virus infection, correlated with postmortem anatomic findings. The 53-year-old patient presented with shortness of breath and productive cough. Examination revealed hypercapnic respiratory failure. Lung computed tomography showed diffuse centrilobular nodules and branching linear opacities, whereas lung biopsy demonstrated diffuse peribronchiolar fibrosis and chronic inflammation with bronchiolectasis. He died 37 days postadmission. Autopsy revealed numerous bronchiolocentric nodules with bronchiolectasis and sheets of foamy macrophages in alveolar septa and spaces. This is a rare example of idiopathic bronchiolitis with features of DPB in an hepatitis C virus-infected African-American patient. Hepatitis C virus infection is known to be associated with extrahepatic pulmonary manifestations, and DPB may be one of these. Early diagnosis will allow appropriate treatment and may slow the disease progression.

Deprivation, ethnicity and prematurity in infant respiratory failure in PICU in the UK.

AIM: To describe the epidemiology of infants admitted to Paediatric Intensive Care (PIC) with acute respiratory failure including bronchiolitis. METHODS: Data from all consecutive admissions from 2004 to 2007 in all 29 designated Paediatric Intensive Care Units (PICUs) in England and Wales were collected. Admission rates, risk-adjusted mortality, length of stay, ventilation status, preterm birth, deprivation and ethnicity were studied. RESULTS: A total of 4641 infants under 1 year of age had an unplanned admission to PIC with acute respiratory failure (ARF), an admission rate of 1.80 per 1000 infants per year. There was a reduced rate of admission with bronchiolitis in South Asian children admitted to PICU, which is not explained by case-mix. Children born preterm had a higher rate of admission and longer stay, but a similar low mortality. Risk-adjusted mortality was higher in South Asian infants and the highest in those with ARF (OR 1.76, 95% CI 1.20-2.57) compared with the rest of the PICU population. CONCLUSION: Acute respiratory failure in infants causes most of the seasonal variation in unplanned admission to intensive care. Socioeconomic deprivation and prematurity are additional risk factors for admission. Fewer South Asian infants are admitted to PICU with a diagnosis of bronchiolitis, but risk-adjusted mortality is higher in South Asian infants overall.

Risks of severity and readmission of Indigenous and non-Indigenous children hospitalised for bronchiolitis.

OBJECTIVE: To describe the characteristics of children admitted to Royal Darwin Hospital with bronchiolitis, and to compare the severity of illness and incidence of subsequent readmission in Indigenous and non-Indigenous children. DESIGN, SETTING AND PARTICIPANTS: Retrospective study of 101 children (aged

Lower respiratory tract infections among american Indian and Alaska Native children and the general population of U.S. Children.

BACKGROUND AND OBJECTIVE: Lower respiratory tract infections (LRTIs) cause substantial childhood morbidity. This study characterizes and compares LRTI-associated morbidity among American Indian/Alaska Native (AI/AN) children and the general population of U.S. children. METHODS: Hospitalization and outpatient records with a diagnosis indicating LRTIs were evaluated for children aged younger than 5 years during 1990-2001. RESULTS: For 1999-2001, the LRTI-associated hospitalization rate was significantly higher for AI/AN children than for U.S. children (116.1 versus 63.2/1000, respectively), with the disparity being greater for infants than for 1- to 4-year-old children. Also the rate of LRTI-associated outpatient visits among AI/AN infants was higher than that for all U.S. infants (737.7 versus 207.2/1000, respectively). LRTI hospitalization and outpatient visit rates were highest in the Alaska and Southwest Indian Health Service regions. During 1990-2001, the LRTI hospitalization rate among AI/AN infants in the Alaska region and among the general U.S. infant population increased. Bronchiolitis-associated hospitalization rates increased for AI/AN and U.S. infants, whereas the pneumonia-associated hospitalization rate decreased among AI/AN infants and remained stable among U.S. infants. CONCLUSIONS: LRTIs continue to be an important cause of morbidity in children, especially among AI/AN infants in the Alaska and Southwest regions. Strategies to reduce LRTI hospitalizations and outpatient visits are warranted for all infants, but the greatest potential impact would be among AI/AN infants.

Respiratory syncytial virus hospitalizations among American Indian and Alaska Native infants and the general United States infant population.

OBJECTIVE: To determine the burden of respiratory syncytial virus (RSV) disease among American Indian (AI) and Alaska Native (AN) infants, by examining RSV-associated hospitalizations. METHODS: Infant hospitalizations from 1997 through 2001 with RSV listed as a diagnosis were selected by using Indian Health Service/tribal hospital discharge data for AIs/ANs and National Hospital Discharge Survey data for the general US population. RESULTS: In 2000-2001, RSV disease was listed as a diagnosis for 14.4% of all AI/AN infant hospitalizations, with bronchiolitis attributable to RSV infection (12.2%) being among the top 5 listed diagnoses. The rate of RSV-specific hospitalizations was 34.4 hospitalizations per 1000 infants for AI/AN infants and 27.4 hospitalizations per 1000 births for the general US infant population. The hospitalization rates for AI/AN infants living in the Alaska and Southwest regions (70.9 and 48.2 hospitalizations per 1000 infants, respectively) were much higher than the overall rate for US infants. CONCLUSIONS: RSV infection is one of the leading causes of hospitalization among all infants in the United States, and AI/AN infants living in the Southwest and Alaska regions are at especially high risk for hospitalizations associated with RSV infection. Development of vaccines, antiviral agents, and other strategies to prevent RSV disease could yield substantial public health benefits.

Diffuse panbronchiolitis in a Caucasian man in Canada.

Diffuse panbronchiolitis (DPB) is a rare, chronic bronchiolar disease in non-Asian populations and is therefore commonly overlooked in Western countries. It usually affects nonsmokers and manifests as persistent air flow obstruction, chronic cough and interstitial nodular opacities. Untreated, the prognosis is poor. In this report the authors describe a Caucasian man of Canadian descent who presented with progressive clinical and lung function impairment despite three years of bronchodilator and corticosteroid treatment with presumed asthma. His chest computed tomography scan showed diffuse centrilobular opacities. Lung biopsy revealed chronic bronchiolitis characterized by infiltration of lymphocytes, plasma cells and foam cells in respiratory and terminal bronchioles, compatible with a diagnosis of DPB. After two months of therapy with clarithromycin, the patient had already shown improvement. Physicians should be aware that DPB may occur in Western countries, and that DPB should be considered in the differential diagnosis of patients with persistent air flow obstruction and nodular shadows on chest radiograms.

Bronchiolitis-associated outpatient visits and hospitalizations among American Indian and Alaska Native children--United States, 1990-2000.

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection (LRTI) in young children worldwide. Approximately half of all LRTI-associated hospitalizations are caused by bronchiolitis, with RSV accounting for 50%-80% of all bronchiolitis cases. Bronchiolitis is an infection of the bronchial and bronchiolar epithelial cells, with subsequent inflammation and edema resulting in airway obstruction. This process manifests clinically as cough, wheezing, tachypnea, and respiratory distress. Because of the association between bronchiolitis and RSV infection, bronchiolitis is a good indicator of RSV disease; therefore, prevention strategies for RSV should reduce the rate of bronchiolitis. Rates of bronchiolitis-associated hospitalization for American Indian/Alaska Native (AI/AN) children are approximately twice that for the general population of U.S. children. This report describes the first estimate of rates of outpatient bronchiolitis-associated visits and updates rates of bronchiolitis-associated hospitalizations in these populations. Rates of bronchiolitis-associated outpatient visits and hospitalizations were higher for AI/AN children than for other U.S. children, and hospitalization rates for both groups increased during 1990-2000. This report underscores the high burden of bronchiolitis and the need for effective prevention programs for AI/AN communities.

Bronchiolitis in Inuit children from a Canadian central arctic community, 1995-1996.

During the winter and summer of 1996 two outbreaks of bronchiolitis occurred among Inuit children in the Canadian arctic community of Arviat. The epidemiology and clinical features of these epidemics were studied through a chart review of bronchiolitis cases occurring from September 1, 1995 to August 31, 1996. The attack rate over the year was 57% and the incidence was 1.25 cases per child-year at risk. The median age of cases was 9 months. Children developing bronchiolitis were more likely to be male (p = 0.006). Respiratory syncytial virus (RSV) was isolated from 17 cases occurring in January/February. The hospitalization rate during those two months was 38%, mortality was 3.3%, and demands upon local health care resources were high. Parainfluenza virus type 3 was isolated from 8 cases occurring during a second smaller outbreak in July/August. Hospitalized children were more likely to be bottle-fed (p = 0.01), and duration of hospitalization was greater for RSV positive versus negative children (p = 0.002). Among those hospitalized 22% required a second admission for the same illness. Identification of prevention strategies awaits an improved understanding of the role of agent, host and environmental factors in the pathophysiology of bronchiolitis in this population.