RNA viruses in community-acquired childhood pneumonia in semi-urban Nepal; a cross-sectional study

Viral and Atypical Bacterial Detection in Young Nepalese Children Hospitalized with Severe Pneumonia

Respiratory viruses cause a substantial proportion of respiratory tract infections in children but are underrecognized as a cause of severe pneumonia hospitalization in low-income settings. We employed 22 real-time PCR assays and retrospectively reanalyzed 610 nasopharyngeal aspirate specimens from children aged 2 to 35 months with severe pneumonia (WHO definition) admitted to Kanti Childrens' Hospital in Kathmandu, Nepal, from January 2006 through June 2008. Previously, ≥1 of 7 viruses had been detected by multiplex reverse transcription-PCR in 30% (188/627) of cases. Reanalyzing the stored specimens, we detected ≥1 pathogens, including 18 respiratory viruses and 3 atypical bacteria, in 98.7% (602/610) of cases. Rhinovirus (RV) and respiratory syncytial virus (RSV) were the most common, detected in 318 (52.1%) and 299 (49%) cases, respectively, followed by adenovirus (AdV) (10.6%), human metapneumovirus (hMPV) (9.7%), parainfluenza virus type 3 (8.4%), and enterovirus (7.7%). The remaining pathogens were each detected in less than 5%. Mycoplasma pneumoniae was most common among the atypical bacteria (3.7%). Codetections were observed in 53.3% of cases. Single-virus detection was more common for hMPV (46%) and RSV (41%) than for RV (22%) and AdV (6%). The mean cycle threshold value for detection of each pathogen tended to be lower in single-pathogen detections than in codetections. This finding was significant for RSV, RV, and AdV. RSV outbreaks occurred at the end of the monsoon or during winter. An expanded diagnostic PCR panel substantially increased the detection of respiratory viruses in young Nepalese children hospitalized with severe pneumonia. IMPORTANCE Respiratory viruses are an important cause of respiratory tract infections in children but are underrecognized as a cause of pneumonia hospitalization in low-income settings. Previously, we detected at least one of seven respiratory viruses by PCR in 30% of young Nepalese children hospitalized with severe pneumonia over a period of 36 months. Using updated PCR assays detecting 21 different viruses and atypical bacteria, we reanalyzed 610 stored upper-respiratory specimens from these children. Respiratory viruses were detected in nearly all children hospitalized for pneumonia. RSV and rhinovirus were the predominant pathogens detected. Detection of two or more pathogens was observed in more than 50% of the pneumonia cases. Single-virus detection was more common for human metapneumovirus and RSV than for rhinovirus and adenovirus. The concentration of virus was higher (low cycle threshold [CT] value) for single detected pathogens, hinting at a high viral load as a marker of clinical significance.

Comprehensive analysis of the association of seasonal variability with maternal and neonatal nutrition in lowland Nepal

OBJECTIVE

To provide a comprehensive seasonal analysis of pregnant mothers' eating behaviour and maternal/newborn nutritional status in an undernourished population from lowland rural Nepal, where weather patterns, agricultural labour, food availability and disease prevalence vary seasonally.

DESIGN

Secondary analysis of cluster-randomised Low Birth Weight South Asia Trial data, applying cosinor analysis to predict seasonal patterns.

OUTCOMES

Maternal mid-upper arm circumference (MUAC), BMI, dietary diversity, meals per day, eating down and food aversion in pregnancy (≥31 weeks' gestation) and neonatal z-scores of length-for-age (LAZ), weight-for-age (WAZ) and head circumference-for-age (HCAZ) and weight-for-length (WLZ).

SETTING

Rural areas of Dhanusha and Mahottari districts in plains of Nepal.

PARTICIPANTS

2831 mothers aged 13-50 and 3330 neonates.

RESULTS

We found seasonal patterns in newborn anthropometry and pregnant mothers' anthropometry, meal frequency, dietary diversity, food aversion and eating down. Seasonality in intake varied by food group. Offspring anthropometry broadly tracked mothers'. Annual amplitudes in mothers' MUAC and BMI were 0·27 kg/m2 and 0·22 cm, with peaks post-harvest and nadirs in October when food insecurity peaked. Annual LAZ, WAZ and WLZ amplitudes were 0·125, 0·159 and 0·411 z-scores, respectively. Neonates were the shortest but least thin (higher WLZ) in winter (December/January). In the hot season, WLZ was the lowest (May/June) while LAZ was the highest (March and August). HCAZ did not vary significantly. Food aversion and eating down peaked pre-monsoon (April/May).

CONCLUSIONS

Our analyses revealed complex seasonal patterns in maternal nutrition and neonatal size. Seasonality should be accounted for when designing and evaluating public heath nutrition interventions.

Hospital utilization rates for influenza and RSV: a novel approach and critical assessment

BACKGROUND

Influenza and respiratory syncytial virus (RSV) contribute significantly to the burden of acute lower respiratory infection (ALRI) inpatient care, but heterogeneous coding practices and availability of inpatient data make it difficult to estimate global hospital utilization for either disease based on coded diagnoses alone.

METHODS

This study estimates rates of influenza and RSV hospitalization by calculating the proportion of ALRI due to influenza and RSV and applying this proportion to inpatient admissions with ALRI coded as primary diagnosis. Proportions of ALRI attributed to influenza and RSV were extracted from a meta-analysis of 360 total sources describing inpatient hospital admissions which were input to a Bayesian mixed effects model over age with random effects over location. Results of this model were applied to inpatient admission datasets for 44 countries to produce rates of hospital utilization for influenza and RSV respectively, and rates were compared to raw coded admissions for each disease.

RESULTS

For most age groups, these methods estimated a higher national admission rate than the rate of directly coded influenza or RSV admissions in the same inpatient sources. In many inpatient sources, International Classification of Disease (ICD) coding detail was insufficient to estimate RSV burden directly. The influenza inpatient burden estimates in older adults appear to be substantially underestimated using this method on primary diagnoses alone. Application of the mixed effects model reduced heterogeneity between countries in influenza and RSV which was biased by coding practices and between-country variation.

CONCLUSIONS

This new method presents the opportunity of estimating hospital utilization rates for influenza and RSV using a wide range of clinical databases. Estimates generally seem promising for influenza and RSV associated hospitalization, but influenza estimates from primary diagnosis seem highly underestimated among older adults. Considerable heterogeneity remains between countries in ALRI coding (i.e., primary vs non-primary cause), and in the age profile of proportion positive for influenza and RSV across studies. While this analysis is interesting because of its wide data utilization and applicability in locations without laboratory-confirmed admission data, understanding the sources of variability and data quality will be essential in future applications of these methods.

A review on disease burden and epidemiology of childhood parainfluenza virus infections in Asian countries

Human parainfluenza viruses (HPIVs) are an important cause of acute respiratory tract infections (ARTIs) in children less than 5 years, second only to human respiratory syncytial viruses (HRSVs). Generally, patients infected with HPIVs are treated in outpatient clinics, yet also contribute to ARTI-associated hospitalization in children. Although HPIV infections are well studied in developed countries, these infections remain under-investigated and not considered in the routine laboratory diagnosis of childhood ARTI in many developing countries in Asia. We performed an extensive literature search on the prevalence, epidemiology, and burden of HPIV infections in children less than 5 years in Asia using PubMed and PubMed Central search engines. Based on the literature, the prevalence of HPIV infection in Asia ranges from 1% to 66%. According to many studies, HPIV-3 is the major virus circulating among children; however, several studies failed to detect HPIV-4 due to unavailability of diagnostic tools. In Asian countries, HPIV contributes a substantial disease burden in children. The data in this review should assist researchers and public health authorities to plan preventive measures, including accelerating research on vaccines and antiviral drugs.

Paramyxoviruses respiratory syncytial virus, parainfluenza virus, and human metapneumovirus infection in pediatric hospitalized patients and climate correlation in a subtropical region of southern China: a 7-year survey

To investigate the features of paramyxovirus respiratory syncytial virus (RSV), parainfluenza virus (PIV), and human metapneumovirus (HMPV) infection and determine the effect of meteorological conditions in Guangzhou, a subtropical region of southern China. We collected 11,398 respiratory samples from hospitalized pediatric patients with acute respiratory illness between July 2009 and June 2016 in Guangzhou. The samples were tested simultaneously for 18 respiratory pathogens using real-time PCR. Local meteorological data were also collected for correlation analysis. Of 11,398 patients tested, 5606 (49.2%) patients tested positive for one or more pathogens; RSV, PIV, and HMPV were the first, sixth, and ninth most frequently detected pathogens, in 1690 (14.8%), 502 (4.4%), and 321 (2.8%) patients, respectively. A total 17.9% (4605/5606) of patients with positive results had coinfection with other pathogens. Significant differences were found in the prevalence of RSV, PIV, and HMPV among all age groups (p < 0.001). RSV and HMPV had similar seasonal patterns, with two prevalence peaks every year. PIV appeared alternatively with RSV and HMPV. Multiple linear regression models were established for RSV, PIV, and HMPV prevalence and meteorological factors (p < 0.05). RSV and PIV incidence was negatively correlated with monthly mean relative humidity; RSV and HMPV incidence was negatively correlated with sunshine duration; PIV incidence was positively correlated with mean temperature. We described the features of paramyxovirus infection in a subtropical region of China and highlighted the correlation with meteorological factors. These findings will assist public health authorities and clinicians in improving strategies for controlling paramyxovirus infection.

A review on epidemiology and impact of human metapneumovirus infections in children using TIAB search strategy on PubMed and PubMed Central articles

Acute respiratory tract infections (ARTI) contribute to morbidity and mortality in children globally. Viruses including human metapneumovirus (hMPV) account for most ARTIs. The virus causes upper and lower respiratory tract infections mostly in young children and contributes to hospitalization of individuals with asthma,chronic obstructive pulmonary diseases and cancer. Moreover, hMPV pauses a considerable socio-economic impact creating a substantial disease burden wherever it has been studied, although hMPV testing is relatively new in many countries. We aimed to comprehensively analyze the epidemiological aspects including prevalence, disease burden and seasonality of hMPV infections in children in the world. We acquired published data extracted from PubMed and PubMed Central articles using the title and abstract (TIAB)search strategy for the major key words on hMPV infections from 9/54 African, 11/35 American, 20/50 Asian, 2/14 Australian/Oceanian and 20/51 European countries. According to the findings of this review, the prevalence of hMPV infection ranges from 1.1 to 86% in children of less than 5 years of age globally. Presence of many hMPV genotypes (A1, A2, B1, B2) and sub-genotypes (A2a, A2b, A2c, B2a, B2b) suggests a rapid evolution of the virus with limited influence by time and geography. hMPV infection mostly affects children between 2 to 5 years of age. The virus is active throughout the year in the tropics and epidemics occur during the winter and spring in temperate climates, contributing to a substantial disease burden globally.

The Impact of RSV-Associated Respiratory Disease on Children in Asia

Acute respiratory tract infections (ARTIs) are leading contributors to the global infectious disease burden, which is estimated to be 112,900,000 disability adjusted life years. Viruses contribute to the etiology of ARTIs in a big way compared with other microorganisms. Since the discovery of respiratory syncytial virus (RSV) 61 years ago, the virus has been recognized as a major cause of ARTI and hospitalization in children. The morbidity and mortality attributable to RSV infection appear to be higher in infants < 3 months and in those with known risk factors such as prematurity, chronic lung, and congenital heart diseases. Crowded living conditions, exposure to tobacco smoke, and industrial or other types of air pollution also increase the risk of RSV-associated ARTI. Many epidemiological studies have been conducted in developed countries to understand the seasonal patterns and risk factors associated with RSV infections. Dearth of information on RSV-associated morbidity and mortality in Asian and developing countries indicates the need for regional reviews to evaluate RSV-associated disease burden in these countries. Epidemiological studies including surveillance is the key to track the disease burden including risk factors, seasonality, morbidity, and mortality associated with RSV infection in these countries. These data will contribute to improve the clinical diagnosis and plan preventive strategies in resource-limited developing countries.

Rapid detection of respiratory syncytial virus in community-acquired lower respiratory tract infections in children by chromatographic assay

Respiratory syncytial virus (RSV) is the single most important viral agent causing pediatric lower respiratory tract infections (LRTIs) worldwide. To evaluate the role of RSV in pediatric LRTIs, we studied 85 children <2 years of age hospitalized for community-acquired LRTIs. Nasopharyngeal aspirates were obtained on admission for the detection of RSV antigen by immunochromatographic assay. Demographic, clinical, and radiological findings for RSV antigen were compared. Data analysis was performed by Chi-square test. A relatively higher number of RSV-infected children 32 (60.4%) were below 6 months of age. Clinical and radiological findings in both RSV-positive and RSV-negative groups were comparable. RSV antigen was positive in 53 (62.4%) with immunochromatography. Our study confirms that RSV plays a significant role in community-acquired LRTIs in children.

Estimation of Burden of Influenza among under-Five Children in India: A Meta-Analysis

BACKGROUND

We estimated the burden of influenza-related acute respiratory tract infection (ARI) among under-fives in India through meta-analysis.

METHODOLOGY

We estimated pooled incidence and proportional positivity of laboratory-diagnosed influenza among under-fives using data from observational studies published from 1 January 1961 to 31 December 2016. Death due to influenza was estimated using a multiplier model.

RESULTS

Influenza-associated ARI incidence was estimated as 132 per 1000 child-years (115-149). The patients positive for influenza among ARI in outpatients and inpatients were estimated to be 11.2% (8.8-13.6) and 7.1% (5.5-8.8), respectively. We estimated total influenza cases during 2016 as 16 009 207 (13 942 916-18 082 769) in India. Influenza accounted for 10 913 476 (9 504 666-12 362 310) outpatient visits and 109 431 (83 882-134 980) hospitalizations. A total of 27 825 (21 382-34 408) influenza-associated under-five deaths were estimated in India in 2016.

CONCLUSION

Influenza imposes a substantial burden among under-fives in India. Public health approach for its prevention and control needs to be explored.

Kitchen PM2.5 concentrations and child acute lower respiratory infection in Bhaktapur, Nepal: The importance of fuel type

BACKGROUND

Globally, solid fuels are used by about 3 billion people for cooking and a smaller number use kerosene. These fuels have been associated with acute lower respiratory infection (ALRI) in children. Previous work in Bhaktapur, Nepal, showed comparable relationships of biomass and kerosene cooking fuels with ALRI in young children, compared to those using electricity for cooking. We examine the relationship of kitchen PM_2.5 concentrations to ALRI in those households.

METHODS

ALRI cases and age-matched controls were enrolled from a cohort of children 2-35 months old. 24-h PM_2.5 was measured once in each participant's kitchen. The main analysis was carried out with conditional logistic regression, with PM_2.5 measures specified both continuously and as quartiles.

RESULTS

In the kitchens of 393 cases and 431 controls, quartiles of increasing PM_2.5 concentration were associated with a monotonic increase in odds ratios (OR): 1.51 (95% CI: 1.00, 2.27), 2.22 (1.47, 3.34), 2.48 (1.63, 3.77), for the 3 highest exposure quartiles. The general kitchen concentration-response shape across all stoves was supralinear. There was evidence for increased risk with biomass stoves, but the slope for kerosene stoves was steeper, the highest quartile OR being 5.36 (1.35, 21.3). Evidence for increased risk was also found for gas stoves.

CONCLUSION

Results support previous reports that biomass and kerosene cooking fuels are both ALRI risk factors, but suggests that PM_2.5 from kerosene is more potent on a unit mass basis. Further studies with larger sample sizes and preferably using electricity as the baseline fuel are needed.

Meteorological factors on the incidence of MP and RSV pneumonia in children

Background

Pneumonia is common in children and mostly caused by many pathogens. The aim of this study was to investigate whether the incidence of pediatric mycoplasma pneumoniae (MP) pneumonia and respiratory syncytial virus (RSV) pneumonia was associated with meteorological factors in Hangzhou, China.

Methods

A total of 36500 pneumonia patients were recruited to participate in the study. Nasopharyngeal swabs were collected for the detection of MP and RSV using real-time polymerase chain reaction (RT-PCR) and direct immunofluorescence (DIF) assays, respectively. We used a distributed lag non-linear model (DLNM) to evaluate the correlations between the MP/RSV incidence and meteorological factors.

Results

The detection rates of MP and RSV were 18.4% and 10.4%, respectively. There was a positive correlation between temperature and the MP infection rate, but RSV infection rate was negatively associated with temperature. Moreover, the impact of temperature on infection with RSV presented evident lag and cumulative effects. There was also an evident lag effect of temperature on the infection rate of MP; however, there was no evident cumulative effect.

Conclusions

In this study, the results showed meteorological factors play an important role in the incidence of these two pathogens. All these results can provide the laboratory basis for the early diagnosis and treatment of pneumonia in children.

Etiology of severe pneumonia in Ecuadorian children

BACKGROUND

In Latin America, community-acquired pneumonia remains a major cause of morbidity and mortality among children. Few studies have examined the etiology of pneumonia in Ecuador.

METHODS

This observational study was part of a randomized, double blind, placebo-controlled clinical trial conducted among children aged 2-59 months with severe pneumonia in Quito, Ecuador. Nasopharyngeal and blood samples were tested for bacterial and viral etiology by polymerase chain reaction. Risk factors for specific respiratory pathogens were also evaluated.

RESULTS

Among 406 children tested, 159 (39.2%) had respiratory syncytial virus (RSV), 71 (17.5%) had human metapneumovirus (hMPV), and 62 (15.3%) had adenovirus. Streptococcus pneumoniae was identified in 37 (9.2%) samples and Mycoplasma pneumoniae in three (0.74%) samples. The yearly circulation pattern of RSV (P = 0.0003) overlapped with S. pneumoniae, (P = 0.03) with most cases occurring in the rainy season. In multivariable analysis, risk factors for RSV included younger age (adjusted odds ratio [aOR] = 1.9, P = 0.01) and being underweight (aOR = 1.8, P = 0.04). Maternal education (aOR = 0.82, P = 0.003), pulse oximetry (aOR = 0.93, P = 0.005), and rales (aOR = 0.25, P = 0.007) were associated with influenza A. Younger age (aOR = 3.5, P = 0.007) and elevated baseline respiratory rate were associated with HPIV-3 infection (aOR = 0.94, P = 0.03).

CONCLUSION

These results indicate the importance of RSV and influenza, and potentially modifiable risk factors including undernutrition and future use of a RSV vaccine, when an effective vaccine becomes available.

TRIAL REGISTRATION

ClinicalTrials.gov NCT 00513929.

Etiology of Acute Respiratory Infections in Infants: A Prospective Birth Cohort Study

BACKGROUND

There is paucity of studies on etiology of acute respiratory infections (ARI) in infants. The objective of this study is to document incidence and etiology of ARI in infants, their seasonal variability and association of clinical profile with etiology.

METHODS

A birth cohort was followed for the first year of life; for each episode of ARI, nasopharyngeal aspirates were collected to identify the causative respiratory virus(es) using multiplex real-time polymerase chain reaction assay. For lower respiratory tract infections blood culture, serum procalcitonin, serum antibodies to Mycoplasma and Chlamydia and urinary Streptococcus pneumoniae antigen were also assayed.

RESULTS

A total of 503 ARI episodes were documented in 310 infants for an incidence rate of 1.8 episodes per infant per year. Of these, samples were processed in 395 episodes (upper respiratory tract infection: 377; lower respiratory tract infection: 18). One or more viruses were detected in 250 (63.3%) episodes and viral coinfections in 72 (18.2%) episodes. Rhinovirus was the most common virus [105 (42%)] followed by respiratory syncytial virus [50 (20%)], parainfluenza virus [42 (16.8%)] and coronavirus [44 (17.6%)]. In lower respiratory tract infections, viral infections were detected in 12 (66.7%) episodes, bacterial infections in 17 (94.4%) episodes and mixed bacterial-viral infections in 8 (44.4%) episodes. Peak incidence of viruses was observed during February-March and September-November. There was no significant difference in symptom duration with virus types.

CONCLUSION

In this cohort of infants, ARI incidence was 1.8 episodes per year per infant; 95% were upper respiratory tract infections. Viruses were identified in 63.3% episodes, and the most common viruses detected were rhinovirus, respiratory syncytial virus and parainfluenza virus.

Epidemiology and Clinical Presentations of Respiratory Syncytial Virus Subgroups A and B Detected with Multiplex Real-Time PCR

Respiratory syncytial virus (RSV) is one of the most important pathogenic infections of children and requires in-depth research worldwide, and especially in developing countries. We used a novel multiplex real-time PCR to test 5483 patients (≤ 14 years old) hospitalized with respiratory illness in Guangzhou, China, over a 3-year period. Of these patients, 729 were positive for RSV-A (51.2%, 373/729) or RSV-B (48.8%, 356/729), but none was infected with both viruses. Two seasonal peaks in total RSV were detected at the changes from winter to spring and from summer to autumn. RSV-B was dominant in 2013 and RSV-A in 2015, whereas RSV-A and RSV-B cocirculated in 2014. The clinical presentations of 645 RSV-positive patients were analyzed. Bronchiolitis, dyspnea, coryza, vomiting, poor appetite, and diarrhea occurred more frequently in RSV-A-positive than RSV-B-positive patients, whereas chill, headache, myalgia, debility, and rash etc. were more frequent in RSV-B-positive than RSV-A-positive patients, suggesting specific clinical characteristics for RSV-A and RSV-B. Coinfectons with other pathogens were common and diverse. Bronchiolitis, fever (≥ 38°C), and poor appetite were more frequent in patients with single RSV infections than in coinfected patients, suggesting the key pathogenic activity of RSV. Analysis of the relationships between the comparative viral load and clinical presentations showed significant differences in bronchiolitis, fever (≥ 38°C), and rash etc. among patients with different viral loads. This study provides a novel rapid method for detecting RSV subgroups, and provides new insights into the epidemiology and clinical implications of RSV.

Respiratory syncytial virus infection in infants in rural Nepal

Objectives

Respiratory syncytial virus (RSV) pneumonia is a leading cause of infant mortality worldwide. The risk of RSV infection associated with preterm birth is not well-characterized in resource-limited settings. We aimed to obtain precise estimates of risk factors and disease burden of RSV in infants in rural southern Nepal.

Methods

Pregnant women were enrolled, and along with their infants, followed to six months after birth with active weekly home-based surveillance for acute respiratory illness (ARI). Mid-nasal swabs were obtained and tested for RSV by PCR for all illness episodes. Birth outcomes were assessed at a postpartum home visit.

Results

311 (9%) of 3509 infants had an RSV ARI. RSV ARI incidence decreased from 551/1000 person-years in infants born between 28 and 31 weeks to 195/1000 person-years in infants born full-term (p = 0.017). Of 220 infants (71%) evaluated in the health system, 41 (19%) visited a hospital or physician. Of 287 infants with an assessment performed, 203 (71%) had a lower respiratory tract infection.

Conclusions

In a rural south Asian setting with intensive home-based surveillance, RSV caused a significant burden of respiratory illness. Preterm infants had the highest incidence of RSV ARI, and should be considered a priority group for RSV preventive interventions in resource-limited settings.

•

RSV caused a significant burden of respiratory illness in infants in rural Nepal.

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The highest incidence of RSV was in preterm infants.

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Most infants with RSV had lower respiratory tract infection or a health care visit.

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Strategies are needed to prevent RSV in preterm infants in resource-limited settings.

Clinical Presentation and Birth Outcomes Associated with Respiratory Syncytial Virus Infection in Pregnancy

Background

Respiratory syncytial virus (RSV) is the most important cause of viral pneumonia in children worldwide. A maternal vaccine may protect both the mother and infant from RSV illness. The epidemiology and clinical presentation of RSV in pregnant and postpartum women is not well-described.

Methods

Data were collected from a prospective, randomized trial of influenza immunization in pregnant women in rural southern Nepal. Women were enrolled in their second trimester of pregnancy and followed until six months postpartum. Active weekly home-based surveillance for febrile respiratory illness was performed. Mid-nasal swabs collected with episodes of respiratory illness were tested for RSV by real-time polymerase chain reaction.

Results

RSV was detected in 14 (0.4%) illness episodes in 3693 women over 3554 person-years of surveillance from 2011–2014. RSV incidence was 3.9/1000 person-years overall, and 11.8/1000 person-years between September and December. Seven (50%) women sought care for RSV illness; none died. Of the 7 (50%) illness episodes during pregnancy, all had live births with 2 (29%) preterm births and a median birthweight of 3060 grams. This compares to 469 (13%) preterm births and a median birthweight of 2790 grams in women without RSV during pregnancy. Of the 7 mothers with postpartum RSV infection, RSV was detected in 4 (57%) of their infants.

Conclusions

RSV was an uncommon cause of febrile respiratory illness in mothers during pregnancy in Nepal. These data will inform prevention and therapeutic strategies against RSV in resource-limited settings.

Cytokine Concentrations in Plasma from Children with Severe and Non-Severe Community Acquired Pneumonia

Background

Children in low and middle-income countries have a high burden of pneumonia. Measuring the cytokine responses may be useful to identify novel markers for diagnosing, monitoring, and treating pneumonia.

Objective

To describe and compare a wide range of inflammatory mediators in plasma from children with WHO-defined severe and non-severe community acquired pneumonia (CAP), and explore to what extent certain mediators are associated with severity and viral detection.

Methods

We collected blood samples from 430 children with severe (n = 43) and non-severe (n = 387) CAP. Plasma from these children were analysed for 27 different cytokines, and we measured the association with age, disease severity and viral detection.

Results

There were generally higher plasma concentrations of several cytokines with both pro-inflammatory and anti-inflammatory effects among children with severe CAP than in children with non-severe CAP. We found significantly higher concentrations of interleukin (IL)-1, IL-4, IL-6, IL-8, IL-9, IL-15, eotaxin, basic fibroblast growth factor (b-FGF), granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor-alpha (TNF-α) in the group of severe CAP. Most of these associations persisted when adjusting for age in linear regression analyses. The cytokine response was strongly associated with age but to a lesser extent with viral etiology.

Conclusion

The plasma concentrations of several cytokines, both with pro-inflammatory and anti-inflammatory effects, were higher among children with severe illness. In particular G-CSF and IL-6 reflected severity and might provide complementary information on the severity of the infection.

Trial registration

ClinicalTrials.gov NCT00148733

Viral aetiology of acute respiratory infections among children and associated meteorological factors in southern China

BACKGROUND

Acute respiratory infections (ARIs) are common in children and mostly caused by viruses, but the significance of the detection of multiple viruses in ARIs is unclear. This study investigated 14 respiratory viruses in ARIs among children and associated meteorological factors in Shantou, southern China.

METHODS

Paired nasal/throat-flocked swabs collected from 1,074 children with ARIs, who visited outpatient walk-in clinics in a tertiary hospital between December 2010 and November 2011, were examined for fourteen respiratory viruses--influenza viruses (FluA, FluB), respiratory syncytial viruses (RSV A and B), human coronaviruses (hCoV: 229E, OC43, HKU1, NL63), human metapneumoviruses (hMPV A and B), parainfluenza viruses (PIV1-4), human rhinoviruses (HRV A, B, C), enteroviruses (EV), adenoviruses (ADV), human bocavirus (hBoV), and human parechoviruses (hPeV)--by multiplex real-time PCR.

RESULTS

We identified at least one virus in 82.3% (884/1,074) and multiple viruses in 38.6% (415/1,074) of patients. EV and HRV were the most frequently detected single viruses (42.3%, 374/884 and 39.9%, 353/884 respectively) and co-detected pair (23.1%, 96/415). Overlapping seasonal trends of viruses were recorded over the year, with dual peaks for EV and single peaks for the others. By logistic regression analysis, EV was positively associated with the average temperature and humidity, hCoV, and PIV4, but negatively with HRV, PIV3, and hBoV. HRV was inversely associated with EV and PIV3.

CONCLUSIONS

This study reports high viral detection and co-detection rates in pediatric ARI cases mainly due to EV and HRV. Many viruses circulated throughout the year with similar seasonal trends in association with temperature, humidity, and wind velocity. Statistically significant associations were present among the viruses. Understanding the polyviral etiology and viral interactions in the cases with multiple viruses warrants further studies.

Incidence of viral infection detected by PCR and real-time PCR in childhood community-acquired pneumonia: a meta-analysis

Several studies examining the incidence of viral infection in childhood community‐acquired pneumonia (CAP) utilizing polymerase chain reaction (PCR) or real‐time PCR methods have been reported. We systematically searched Pubmed and Embase for studies reporting the incidence of respiratory viral infection in childhood CAP. The pooled incidences of viral infection were calculated with a random‐effects model. Sources of heterogeneity were explored by subgroup analysis and a univariant metaregression analysis. We included 21 eligible reports in our study. We found significant heterogeneity on the incidence of viral infection in childhood CAP. The random effects pooled incidence was 57.4% (95% confidence interval (CI): 50.8–64.1). The pooled incidence of mixed infection was 29.3% (95%CI: 23.0–35.6) with considerable heterogeneity. The pooled incidence of mixed infection was 29.3% (95%CI: 23.0–35.6). Rhinovirus, respiratory syncytial virus (RSV) and bocavirus were found to be the three most common viruses in childhood CAP. We also demonstrated that respiratory viruses were detected in 76.1% of patients aged ≤1 year, 63.1% of patients aged 2–5 years and 27.9% of patients aged ≥ 6 years. We conclude that respiratory viruses are widely detected in paediatric patients with CAP by PCR or real‐time PCR methods. More than half of viral infections are probably concurrent with bacterial infections. Rhinovirus, RSV and bocavirus are the three most frequent viruses identified in childhood CAP; the incidence of viral infection decreased with age.

Epidemiology, etiology, x-ray features, importance of co-infections and clinical features of viral pneumonia in developing countries

Pneumonia is still the number one killer of young children globally, accounting for 18% of mortality in children under 5 years of age. An estimated 120 million new cases of pneumonia occur globally each year. In developing countries, management and prevention efforts against pneumonia have traditionally focused on bacterial pathogens. More recently however, viral pathogens have gained attention as a result of improved diagnostic methods, such as polymerase chain reaction, outbreaks of severe disease caused by emerging pathogens, discovery of new respiratory viruses as well as the decrease in bacterial pneumonia as a consequence of the introduction of highly effective conjugate vaccines. Although the epidemiology, etiology and clinical characterization of viral infections are being studied extensively in the developed world, little data are available from low- and middle-income countries. In this paper, we review the epidemiology, etiology, clinical and radiological features of viral pneumonia in developing countries.

Epidemiology of acute respiratory infections in children in Guangzhou: a three-year study

Acute Respiratory Infections (ARI) are some of the most common human diseases worldwide. However, they have a complex and diverse etiology, and the characteristics of the pathogens involved in respiratory infections in developing countries are not well understood. In this work, we analyzed the characteristics of 17 common respiratory pathogens in children (≤14 years old) with ARI in Guangzhou, southern China over a 3-year period using real-time polymerase chain reaction. Pathogens were identified in 2361/4242 (55.7%) patients, and the positivity rate varied seasonally. Ten of the 17 pathogens investigated showed positivity rates of more than 5%. The most frequently detected pathogens were respiratory syncytial virus (768/2361, 32.5%), influenza A virus (428/2361, 18.1%), enterovirus (138/2361, 13.3%), Mycoplasma pneumoniae (267/2361, 11.3%) and adenovirus (213/2361, 9.0%). Co-pathogens were common and found in 503 of 2361 (21.3%) positive samples. When ranked according to frequency of occurrence, the pattern of co-pathogens was similar to that of the primary pathogens, with the exception of human bocavirus, human coronavirus and human metapneumovirus. Significant differences were found in age prevalence in 10 of the 17 pathogens (p≤0.009): four basic patterns were observed, A: detection rates increased with age, B: detection rates declined with age, C: the detection rate showed distinct peaks or D: numbers of patients were too low to detect a trend or showed no significant difference among age groups (p>0.05). These data will be useful for planning vaccine research and control strategies and for studies predicting pathogen prevalence.

Incidence and etiology of acute lower respiratory tract infections in hospitalized children younger than 5 years in rural Thailand

BACKGROUND

Pneumonia remains a leading cause of under-five morbidity and mortality globally. Comprehensive incidence, epidemiologic and etiologic data are needed to update prevention and control strategies.

METHODS

We conducted active, population-based surveillance for hospitalized cases of acute lower respiratory tract infections (ALRI) among children <5 years of age in rural Thailand. ALRI cases were systematically sampled for an etiology study that tested nasopharyngeal specimens by polymerase chain reaction; children without ALRI were enrolled as controls from outpatient clinics.

RESULTS

We identified 28,543 hospitalized ALRI cases from 2005 to 2010. Among the 49% with chest radiographs, 76% had findings consistent with pneumonia as identified by 2 study radiologists. The hospitalized ALRI incidence rate was 5772 per 100,000 child-years (95% confidence interval: 5707, 5837) and was higher in boys versus girls (incidence rate ratio 1.38, 95% confidence interval: 1.35-1.41) and in children 6-23 months of age versus other age groups (incidence rate ratio 1.76, 95% confidence interval: 1.69-1.84). Viruses most commonly detected in ALRI cases were respiratory syncytial virus (19.5%), rhinoviruses (18.7%), bocavirus (12.8%) and influenza viruses (8%). Compared with controls, ALRI cases were more likely to test positive for respiratory syncytial virus, influenza, adenovirus, human metapneumovirus and parainfluenza viruses 1 and 3 (P ≤ 0.01 for all). Bloodstream infections, most commonly Streptococcus pneumoniae and nontyphoidal Salmonella, accounted for 1.8% of cases.

CONCLUSIONS

Our findings underscore the high burden of hospitalization for ALRI and the importance of viral pathogens among children in Thailand. Interventions targeting viral pathogens coupled with improved diagnostic approaches, especially for bacteria, are critical for better understanding of ALRI etiology, prevention and control.

Diagnostic features of community-acquired pneumonia in children: what's new?

AIM

To critically summarise the available data on diagnosis of CAP in children, focusing on the newest findings and on the need for new studies.

METHODS

Eighty studies on the diagnosis of paediatric community-acquired pneumonia were scrutinised.

RESULTS

We found no significant associations between the signs or symptoms and aetiology of pneumonia and concluded that chest radiographs remain controversial and real-time polymerase chain reaction appears more sensitive than blood cultures.

CONCLUSION

Antibiotic overuse could make it difficult to differentiate viral and bacterial causes. Molecular methods provide promising tools for diagnosing infection by atypical bacteria, but are expensive and should be used selectively.

Respiratory virus surveillance in hospitalised pneumonia patients on the Thailand-Myanmar border

Background

Pneumonia is a significant cause of morbidity and mortality in the developing world. Viruses contribute significantly to pneumonia burden, although data for low-income and tropical countries are scarce. The aim of this laboratory-enhanced, hospital-based surveillance was to characterise the epidemiology of respiratory virus infections among refugees living on the Thailand-Myanmar border.

Methods

Maela camp provides shelter for ~45,000 refugees. Inside the camp, a humanitarian organisation provides free hospital care in a 158-bed inpatient department (IPD). Between 1st April 2009 and 30th September 2011, all patients admitted to the IPD with a clinical diagnosis of pneumonia were invited to participate. Clinical symptoms and signs were recorded and a nasopharyngeal aspirate (NPA) collected. NPAs were tested for adenoviruses, human metapneumovirus (hMPV), influenza A & B, and RSV by PCR.

Results

Seven hundred eight patient episodes (698 patients) diagnosed as pneumonia during the enhanced surveillance period were included in this analysis. The median patient age was 1 year (range: < 1-70), and 90.4% were aged < 5 years. At least one virus was detected in 53.7% (380/708) of episodes. Virus detection was more common in children aged < 5 years old (<1 year: OR 2.0, 95% CI 1.2-3.4, p = 0.01; 1-4 years: OR 1.4, 95% CI 0.8-2.3, p = 0.2). RSV was detected in 176/708 (24.9%); an adenovirus in 133/708 (18.8%); an influenza virus in 68/708 (9.6%); and hMPV in 33/708 (4.7%). Twenty-eight episodes of multiple viral infections were identified, most commonly adenovirus plus another virus. RSV was more likely to be detected in children <5 years (OR 12.3, 95% CI 3.0-50.8, p = 0.001) and influenza viruses in patients ≥5 years (OR 2.8, 95% CI 1.5-5.4, p = 0.002). IPD treatment was documented in 702/708 cases; all but one patient received antimicrobials, most commonly a beta-lactam (amoxicillin/ampicillin +/−gentamicin in 664/701, 94.7%).

Conclusions

Viral nucleic acid was identified in the nasopharynx in half the patients admitted with clinically diagnosed pneumonia. Development of immunisations targeting common respiratory viruses is likely to reduce the incidence of pneumonia in children living refugee camps and similar settings.

The epidemiology of hospitalization for pneumonia in children under five in the rural western region of Nepal: a descriptive study

Pneumonia is one of the major public health problems in children under five years of age. The aim of this study was to analyze the time, place, and characteristics of the distribution of pneumonia in hospitalized children under five years of age at the Dhaulagiri Zonal Hospital (DZH) in Nepal. A descriptive cross-sectional study was carried out at DZH from July 16, 2008 to August 17, 2011 for hospitalized children under five years of age and diagnosed with pneumonia. The main bacterial cause of pneumonia was Streptococcus pneumoniae and the main viral cause was Respiratory Syntical Virus (RSV). The majority of children admitted for treatment of pneumonia were males (60%), from upper class ethnic groups, and common among those aged 29 days to one year (49.1% of overall pneumonia cases). Data from this study show that pneumonia episodes in DZH occurred throughout the year with a sharp increase in the occurrence at the end of August to September. More cases were recorded during the rainy seasons and winter months in all three study years. The cases were from households most concentrated in Baglung municipality where the hospital is located. Pneumonia was found in higher proportions among hospitalized male children, those aged 29 days to one year, and in upper ethnic groups, during the rainy seasons and in winter months, and among local populations near the hospital in the rural western region of Nepal. Strengthening community-based case management, prevention strategies, and health care delivery system would help reduce pneumonia cases and the overall burden associated with it.

Case/control studies with follow-up: Constructing the source population to estimate effects of risk factors on development, disease, and survival

If individuals in a case/control study are subsequently observed as a cohort of cases and a cohort of controls, weighted regression analyses can be used to estimate the association between the exposures initially recorded and events occurring during the follow-up of the 2 cohorts. Such analyses can be conceptualized as being undertaken on a reconstructed source population from which cases and controls stem. To simulate this population, the cohort of cases is added to the cohort of controls expanded with the reciprocal of the case disease incidence odds (the sampling weight) to include all individuals in the source population who did not develop the case disease. We use a simulated dataset to illustrate how weighted generalized linear model regression can be used to estimate the association between an exposure captured during the case/control study component and an outcome that occurs during follow-up.

Acute lower respiratory infection in childhood and household fuel use in Bhaktapur, Nepal

BACKGROUND

Globally, solid fuels are used by about 3 billion people for cooking. These fuels have been associated with many health effects, including acute lower respiratory infection (ALRI) in young children. Nepal has a high prevalence of use of biomass for cooking and heating.

OBJECTIVE

This case-control study was conducted among a population in the Bhaktapur municipality, Nepal, to investigate the relationship of cookfuel type to ALRI in young children.

METHODS

Cases with ALRI and age-matched controls were enrolled from an open cohort of children 2-35 months old, under active monthly surveillance for ALRI. A questionnaire was used to obtain information on family characteristics, including household cooking and heating appliances and fuels. The main analysis was carried out using conditional logistic regression. Population-attributable fractions (PAF) for stove types were calculated.

RESULTS

A total of 917 children (452 cases and 465 controls) were recruited into the study. Relative to use of electricity for cooking, ALRI was increased in association with any use of biomass stoves [odds ratio (OR) = 1.93; 95% CI: 1.24, 2.98], kerosene stoves (OR = 1.87; 95% CI: 1.24, 2.83), and gas stoves (OR = 1.62; 95% CI: 1.05, 2.50). Use of wood, kerosene, or coal heating was also associated with ALRI (OR = 1.45; 95% CI: 0.97, 2.14), compared with no heating or electricity or gas heating. PAFs for ALRI were 18.0% (95% CI: 8.1, 26.9%) and 18.7% (95% CI: 8.4%-27.8%), for biomass and kerosene stoves, respectively.

CONCLUSIONS

The study supports previous reports indicating that use of biomass as a household fuel is a risk factor for ALRI, and provides new evidence that use of kerosene for cooking may also be a risk factor for ALRI in young children.

Chinese medicinal herbs for childhood pneumonia: a systematic review of effectiveness and safety

Objective. To assess the efficacy and safety of Chinese medicinal herbs for Childhood Pneumonia. Methods. We included randomized controlled trials (RCTs). The searched electronic databases included PubMed, the Cochrane Central Register of Controlled Trials, EMBASE, CBM, CNKI, and VIP. All studies included were assessed for quality and risk bias. Review Manager 5.1.6 software was used for data analyses, and the GRADEprofiler software was applied to classify the systematic review results. Results. Fourteen studies were identified (n = 1.824). Chinese herbs may increase total effective rate (risk ratio (RR) 1.18; 95% confidence interval (CI), 1.11–1.26) and improve cough (total mean difference (MD), −2.18; 95% CI, (−2.66)–(−1.71)), fever (total MD, −1.85; 95% CI, (−2.29)–(−1.40)), rales (total MD, −1.53; 95% CI, (−1.84)–(−1.23)), and chest films (total MD, −3.10; 95% CI, (−4.11)–(−2.08)) in Childhood Pneumonia. Chinese herbs may shorten the length of hospital stay (total MD, −3.00; 95% CI, (−3.52)–(−2.48)), but no significant difference for adverse effects (RR, 0.39; 95% CI, 0.09–1.72) was identified. Conclusion. Chinese herbs may increase total effective rate and improve symptoms and signs. However, large, properly randomized, placebo-controlled, double-blind studies are required.

Latitudinal variations in seasonal activity of influenza and respiratory syncytial virus (RSV): a global comparative review

BACKGROUND

There is limited information on influenza and respiratory syncytial virus (RSV) seasonal patterns in tropical areas, although there is renewed interest in understanding the seasonal drivers of respiratory viruses.

METHODS

We review geographic variations in seasonality of laboratory-confirmed influenza and RSV epidemics in 137 global locations based on literature review and electronic sources. We assessed peak timing and epidemic duration and explored their association with geography and study settings. We fitted time series model to weekly national data available from the WHO influenza surveillance system (FluNet) to further characterize seasonal parameters.

RESULTS

Influenza and RSV activity consistently peaked during winter months in temperate locales, while there was greater diversity in the tropics. Several temperate locations experienced semi-annual influenza activity with peaks occurring in winter and summer. Semi-annual activity was relatively common in tropical areas of Southeast Asia for both viruses. Biennial cycles of RSV activity were identified in Northern Europe. Both viruses exhibited weak latitudinal gradients in the timing of epidemics by hemisphere, with peak timing occurring later in the calendar year with increasing latitude (P<0.03). Time series model applied to influenza data from 85 countries confirmed the presence of latitudinal gradients in timing, duration, seasonal amplitude, and between-year variability of epidemics. Overall, 80% of tropical locations experienced distinct RSV seasons lasting 6 months or less, while the percentage was 50% for influenza.

CONCLUSION

Our review combining literature and electronic data sources suggests that a large fraction of tropical locations experience focused seasons of respiratory virus activity in individual years. Information on seasonal patterns remains limited in large undersampled regions, included Africa and Central America. Future studies should attempt to link the observed latitudinal gradients in seasonality of viral epidemics with climatic and population factors, and explore regional differences in disease transmission dynamics and attack rates.

Challenges to evaluating respiratory syncytial virus mortality in Bangladesh, 2004-2008

Background

Acute lower respiratory illness is the most common cause of death among children, globally. Data are not available to make accurate estimates on the global mortality from respiratory syncytial virus (RSV), specifically.

Methods

Respiratory samples collected from children under 5 years of age during 2004 to 2008 as part of population-based respiratory disease surveillance in an urban community in Dhaka, Bangladesh were tested for RSV, human metapneumovirus (HMPV), human parainfluenza virus (PIV) types 1, 2, and 3, influenza and adenovirus by RT-PCR. Verbal autopsy data were used to identify children who died from respiratory illness in a nearby rural community. Significance of the correlation between detections and community respiratory deaths was determined using Spearman's coefficient.

Results

RSV activity occurred during defined periods lasting approximately three months but with no clear seasonal pattern. There was no significant correlation between respiratory deaths and detection of any of the respiratory viruses studied.

Conclusion

Outbreaks of respiratory viruses may not be associated with deaths in children in the study site; however, the few respiratory deaths observed and community-to-community variation in the timing of outbreaks may have obscured an association. An accurate assessment of respiratory virus-associated deaths will require detections and death data to come from the same location and a larger study population.

Respiratory viruses from hospitalized children with severe pneumonia in the Philippines

BACKGROUND

Pneumonia remains a leading cause of child death in developing countries. The viruses in severe pneumonia remain poorly defined.

METHODS

The study was conducted at the Eastern Visayas Regional Medical Center in Tacloban City, Philippines from May 2008 to May 2009. Patients aged 8 days to 13 years old who were admitted to the Department of Pediatrics with severe pneumonia were enrolled for the study. Upon admission, polymerase chain reaction was performed using nasopharyngeal swabs and blood cultures to detect respiratory viruses and bacteria, respectively.

RESULT

Among the 819 patients enrolled, at least one virus was detected in 501 cases (61.2%). In addition, 423 cases were positive for a single virus while bacteria were detected in the blood culture sample of 31 cases. The most commonly detected viruses were human rhinoviruses (n = 189), including types A (n = 103), B (n = 17), and C (n = 69), and respiratory syncytial virus (RSV) (n = 165). Novel viruses such as human metapneumovirus, human coronavirus NL63, human bocavirus, and human polyomaviruses WU and KI were also detected. There were 70 deaths, and one or more viruses were detected in 35 (50%) of these cases. Positivity only for influenza A virus (OR = 4.3, 95% CI = 1.3-14.6) was significantly associated with fatal outcome. From the blood culture, Burkholderia cepacia group (n = 9), Streptococcus pneumoniae (n = 4), Staphylococcus aureus (n = 4), Haemophilus influenzae (n = 1), and Salmonella C1 (n = 1) were also isolated.

CONCLUSION

Viruses were commonly detected in children with severe pneumonia in the Philippines. Hence, viral etiologies should be considered while developing better effective strategies to reduce child pneumonia-related deaths in developing countries.

Seasonal distribution and epidemiological characteristics of human metapneumovirus infections in pediatric inpatients in Southeast China

Human metapneumovirus (hMPV) is an important respiratory pathogen in young children whose seasonal activity varies substantially from year to year among different populations. This study was conducted to investigate if there was a seasonal variation in the incidence of hMPV infection in young children and possible associations between hMPV infection and local meteorological parameters in Suzhou, China. A total of 6,655 children with acute respiratory tract infection (ARTI) admitted to the Children’s Hospital affiliated to Soochow University, Suzhou, were tested from January 2006 to December 2009 for the presence of hMPV using reverse-transcription polymerase chain reaction. The relationship between the presence of the virus and regional meteorological conditions was analyzed by linear and multivariate regression analysis. The overall hMPV infection incidence over the four-year study was 8.2 %, 8.1 %, 12.7 % and 7.4 % per year, respectively. Four hundred eighty-eight hMPV-positive children (78.2 %) were younger than 3 years of age. hMPV infections appear to have a seasonal distribution in Suzhou. In 2006, 2007 and 2009, the peak seasons were in December to January, while in 2008, the peak of hMPV activity occurred in May. The incidence of hMPV infection was negatively correlated with the average monthly temperature and rainfall. hMPV was one of the most common viral pathogens after respiratory syncytial virus that was associated with acute respiratory tract infection in children in Suzhou. hMPV infection occurred throughout the year with peaks during late winter and early spring. Climatic factors, especially monthly average temperature, may affect the prevalence of hMPV in Suzhou.

Epidemiology of respiratory virus infections among infants and young children admitted to hospital in Oman

The aim of this prospective study was to determine the epidemiology of respiratory viruses responsible for seasonal epidemics of influenza‐like illness in infants and young children in Oman. All children ≤5 years of age consecutively admitted to Sultan Qaboos University Hospital in Oman over a 1‐year period between December 2007 and December 2008 with acute respiratory infections were included. A multiplex polymerase chain reaction (PCR) for viral detection was performed on nasopharyngeal aspirates. Analyses were conducted using univariate statistical methods. Of the 259 infants and young children, at least one respiratory virus was detected in 130 samples (50%). The most prevalent viruses were respiratory syncytial virus (RSV; 43%; n = 56), adenovirus (15%; n = 20), and parainfluenza virus (PIV) (11%; n = 14). Dual or multiple viral infections were found in 23 cases (18%). The three most prominent symptoms of the cohort were fever (78%; n = 201), tachypnoea (77%; n = 200), and runny nose (61%; n = 158). The majority had bronchiolitis (39%; n = 101) while 37% (n = 96) had pneumonia. RSV was more likely to affect those that were young (4 months vs. 7.5 months; P = 0.002) and had tachypnoea (93% vs. 69%; P = 0.004), lower respiratory tract infections (91% vs. 80%; P = 0.039), and bronchiolitis (57% vs. 38%; P = 0.024). The study indicated that respiratory viruses are highly prevalent in children ≤5 years presenting with acute respiratory infections in Oman, of which RSV is the most prominent. J. Med. Virol. 84: 1323–1329, 2012. © 2012 Wiley Periodicals, Inc.

Human Metapneumovirus: lessons learned over the first decade

It has been 10 years since human metapneumovirus (HMPV) was identified as a causative agent of respiratory illness in humans. Since then, numerous studies have contributed to a substantial body of knowledge on many aspects of HMPV. This review summarizes our current knowledge on HMPV, HMPV disease pathogenesis, and disease intervention strategies and identifies a number of areas with key questions to be addressed in the future.

A literature review and survey of childhood pneumonia etiology studies: 2000-2010

The Pneumonia Etiology Research for Child Health (PERCH) project is the largest multicountry etiology study of childhood pneumonia since the Board on Science and Technology in International Development studies of the 1980s. However, it is not the only recent or ongoing pneumonia etiology study, and even with seven sites, it cannot capture all epidemiologic settings in the developing world. Funding providers, researchers and policymakers rely on the best available evidence to strategically plan programs, new research directions and interventions. We aimed to describe the current landscape of recent pneumonia etiology studies in children under 5 years of age in the developed and developing world, as ascertained by a literature review of relevant studies with data since the year 2000 and a survey of researchers in the field of childhood pneumonia. We collected information on the study population, study design, case definitions, laboratory samples and methods and identified pathogens. A literature review identified 88 studies with child pneumonia etiology results. As of June 2010, our survey of researchers identified an additional 65 ongoing and recently completed child pneumonia etiology studies. This demonstrates the broad existing context into which the PERCH study must be placed. However, the landscape analysis also reveals a multiplicity of case definitions, levels of clinician involvement, facility types, specimen collection, and laboratory techniques. It reinforces the need for the standardization of methods and analyses for present and future pneumonia etiology studies in order to optimize their cumulative potential to accurately describe the microbial causes of childhood pneumonia.

Detection and genetic diversity of human metapneumovirus in hospitalized children with acute respiratory infections in India

Human metapneumovirus (hMPV) causes acute respiratory infections in children and adults. It is classified into two major genetic lineages and each lineage into two sublineages. The purpose of the study was to identify and characterize hMPV in children who presented to the All India Institute of Medical Sciences, New Delhi, India with acute respiratory infection from April 2005 to March 2007. By reverse-transcription polymerase chain reaction, hMPV was detected in 21 (3%) of the 662 nasopharyngeal samples from children with acute respiratory infection and in none of the 120 control children. Seven of the 21 (33%) children infected with hMPV required hospital admission for pneumonia or bronchiolitis. Most hMPV detections were during the winter and spring seasons. The majority (67%, 11/21) of children positive for hMPV were within 24 months of age. Phylogenetic analysis of partial F and N gene and the full G gene sequences showed three sub-lineages of hMPV circulated during the study period, B1, B2, and the novel sub-lineage A2b. The circulation pattern of hMPV genotypes varied by season. Comparison of the F and G genes of eight strains revealed incongruencies in lineage assignments, raising the possibility that recombination had occurred. Sequence analysis also revealed the F gene was relatively conserved whereas the G gene was more variable between the A and B lineages. This study demonstrates that hMPV is an important contributor to acute respiratory infection in children in India, resulting in both outpatient visits and hospitalizations.

Progress in respiratory virus vaccine development

Viral respiratory infections cause significant morbidity and mortality in infants and young children as well as in at-risk adults and the elderly. Although many viral pathogens are capable of causing respiratory disease, vaccine development has to focus on a limited number of pathogens, such as those that commonly cause serious lower respiratory illness (LRI). Whereas influenza virus vaccines have been available for some time (see the review by Clark and Lynch in this issue), vaccines against other medically important viruses such as respiratory syncytial virus (RSV), the parainfluenza viruses (PIVs), and metapneumovirus (MPVs) are not available. This review aims to provide a brief update on investigational vaccines against RSV, the PIVs, and MPV that have been evaluated in clinical trials or are currently in clinical development.

Influenza vaccine for pregnant women in resource-constrained countries: a review of the evidence to inform policy decisions

Seasonal influenza is responsible for three to five million severe cases of disease annually, and up to 500,000 deaths worldwide. Pregnant women and infants suffer disproportionately from severe outcomes of influenza. The excellent safety profile and reliable immunogenicity of inactivated influenza vaccine support WHO recommendations that pregnant women be vaccinated to decrease complications of influenza disease during pregnancy. Nevertheless, influenza vaccine is not routinely used in most low-and middle-income countries and is not widely used in pregnant women worldwide. Two recent prospective, controlled trials of maternal influenza vaccination in Bangladesh and US Native American reservations demonstrated that inactivated influenza vaccine given to pregnant women can decrease laboratory-confirmed influenza virus infection in their newborn children. These studies support consideration of the feasibility of targeted influenza vaccine programs in resource-constrained countries. Platforms exist for the delivery of influenza vaccine to pregnant women worldwide. Even in the least developed countries, an estimated 70% of women receive antenatal care, providing an opportunity for targeted influenza vaccination. Challenges to the introduction of maternal influenza vaccination in resource-constrained countries exist, including issues regarding vaccine formulation, availability, and cost. Nonetheless, maternal influenza vaccination remains an important and potentially cost-effective approach to decrease influenza morbidity in two high-risk groups - pregnant women and young infants.

Acute lower respiratory tract infection due to respiratory syncytial virus in a group of Egyptian children under 5 years of age

BACKGROUND AND AIM

Respiratory syncytial virus (RSV) is one of the most important causes of acute lower respiratory tract infections (ALRTI) in infants and young children. This study was conducted to describe the epidemiology of ALRTI associated with RSV among children ≤ 5 years old in Egypt.

PATIENTS AND METHODS

We enrolled 427 children ≤ 5 years old diagnosed with ALRTI attending the outpatient clinic or Emergency Department (ED) of Children Hospital, Cairo University during a one- year period. Nasopharyngeal aspirates were obtained from the patients, kept on ice and processed within 2 hours of collection. Immunoflourescent assay (IFA) for RSV was performed.

RESULTS

91 cases (21.3%) had viral etiology with RSV antigens detected in 70 cases (16.4%). The RSV positive cases were significantly younger than other non-RSV cases (mean age 8.2 months versus 14.2 months, p <0.001). RSV cases had significantly higher respiratory rate in the age group between 2-11 months (mean 58.4 versus 52.7/minute, p < 0.001) and no significant difference in the mean respiratory rate in the age group between 12-59 months. More RSV cases required supplemental oxygen (46% versus 23.5%, p < 0.001) with higher rate of hospitalization (37.1% versus 11.2%, p < 0.001) than the non-RSV cases. 97% of RSV cases occurred in winter season (p < 0.001).

CONCLUSION

RSV is the most common viral etiology of ALRTI in children below 5 years of age, especially in young infants below 6 months of age. It is more prevalent in winter and tends to cause severe infection.

Viral etiology of influenza-like illnesses in Antananarivo, Madagascar, July 2008 to June 2009

BACKGROUND

In Madagascar, despite an influenza surveillance established since 1978, little is known about the etiology and prevalence of viruses other than influenza causing influenza-like illnesses (ILIs).

METHODOLOGY/PRINCIPAL FINDINGS

From July 2008 to June 2009, we collected respiratory specimens from patients who presented ILIs symptoms in public and private clinics in Antananarivo (the capital city of Madagascar). ILIs were defined as body temperature ≥38°C and cough and at least two of the following symptoms: sore throat, rhinorrhea, headache and muscular pain, for a maximum duration of 3 days. We screened these specimens using five multiplex real time Reverse Transcription and/or Polymerase Chain Reaction assays for detection of 14 respiratory viruses. We detected respiratory viruses in 235/313 (75.1%) samples. Overall influenza virus A (27.3%) was the most common virus followed by rhinovirus (24.8%), RSV (21.2%), adenovirus (6.1%), coronavirus OC43 (6.1%), influenza virus B (3.9%), parainfluenza virus-3 (2.9%), and parainfluenza virus-1 (2.3%). Co-infections occurred in 29.4% (69/235) of infected patients and rhinovirus was the most detected virus (27.5%). Children under 5 years were more likely to have one or more detectable virus associated with their ILI. In this age group, compared to those ≥5 years, the risk of detecting more than one virus was higher (OR = 1.9), as was the risk of detecting of RSV (OR = 10.1) and adenovirus (OR = 4.7). While rhinovirus and adenovirus infections occurred year round, RSV, influenza virus A and coronavirus OC43 had defined period of circulation.

CONCLUSIONS

In our study, we found that respiratory viruses play an important role in ILIs in the Malagasy community, particularly in children under 5 years old. These data provide a better understanding of the viral etiology of outpatients with ILI and describe for the first time importance of these viruses in different age group and their period of circulation.

Pneumonia - management in the developing world

Childhood pneumonias are an important cause of morbidity and mortality and annually contribute to over 2 million deaths among children under five years of age. To combat this, a standardized case management protocol developed by the World Health Organization has been adopted by the National programs in most high burden, resource constrained settings. This can detect patients with pneumonia early on and with ease at community level and also identify those who are at risk of dying due to a severe form of the disease if not referred or appropriately treated. However, as most deaths due to pneumonia occur in health facilities, it is equally important to standardise treatment at a facility level with pulse oximetry, regular monitoring for complications and the judicious use of antibiotics. The challenge is to identify other respiratory illnesses which mimic pneumonia resulting in under treatment with bronchodilators and over usage of antibiotics. This becomes particularly important in developing countries which have the dual burden of both the infectious and non-infectious illnesses. The strategy also needs refinement for diagnosing and treating pneumonia in severely under nourished and / or HIV co-infected children who are both at higher risk of disease as well as death due to it.

Two weeks of zinc administration to Nepalese children with pneumonia does not reduce the incidence of pneumonia or diarrhea during the next six months

Diarrhea and pneumonia are the 2 main causes of death in children under 5 y of age. Short courses of zinc administration are now recommended for treatment of childhood diarrhea and some studies have also shown its beneficial effect on treatment of pneumonia. The objective of our study was to assess the efficacy of zinc administration (10 mg/d for children 2-11 mo and 20 mg/d for >or= 12 mo of age) for 14 d on preventing diarrheal and respiratory illnesses for 6 mo of follow-up. This was a randomized, double-blind, placebo-controlled trial in children 2-35 mo of age with community-acquired pneumonia. The number of illness episodes and time until the first episode of various illnesses were compared between the 2 study groups. After 14 d of zinc supplementation, plasma zinc was significantly higher in the group receiving zinc. However, this difference was not detectable at 1 and 2.5 mo after the end of zinc administration. Of 2628 enrolled cases, a total of 2599 (99%) were available for assessment after the completion of zinc supplementation. The number of hospital visits and the median number of days until the first episode of pneumonia, diarrhea, and dysentery was similar in the 2 groups. The hazard ratios (95% CI) were 1.02 (0.92, 1.14) for nonsevere pneumonia, 1.11 (0.72, 1.73) for severe pneumonia, 1.07 (0.91, 1.26) for diarrhea, and 0.96 (0.69, 1.34) for dysentery. A short course of zinc supplementation given during an episode of pneumonia did not prevent diarrheal or respiratory illness over the next 6 mo.

A randomized controlled trial of the effect of zinc as adjuvant therapy in children 2-35 mo of age with severe or nonsevere pneumonia in Bhaktapur, Nepal

BACKGROUND

Pneumonia is a leading cause of illness and death in young children. Interventions to improve case management of pneumonia are needed.

OBJECTIVE

Our objective was to measure the effect of zinc supplementation in children with pneumonia in a population in which zinc deficiency is common.

DESIGN

In a double-blind, placebo-controlled clinical trial, children aged 2-35 mo with severe (n = 149) or nonsevere (n = 2479) pneumonia defined according to criteria established by the World Health Organization were randomly assigned to receive zinc (10 mg for children aged 2-11 mo, 20 mg for children aged > or =12 mo) or placebo daily for 14 d as an adjuvant to antibiotics. The primary outcomes were treatment failure, defined as a need for change in antibiotics or hospitalization, and time to recovery from pneumonia.

RESULTS

One of 5 children did not respond adequately to antibiotic treatment; the odds ratios between zinc and placebo groups for treatment failure were 0.95 (95% CI: 0.78, 1.2) for nonsevere pneumonia and 0.97 (95% CI: 0.42, 2.2) for severe pneumonia. There was no difference in time to recovery between zinc and placebo groups for nonsevere (median: 2 d; hazard ratio: 1.0; 95% CI: 0.96, 1.1) or severe (median: 4 d; hazard ratio: 1.1; 95% CI: 0.79, 1.5) pneumonia. Regurgitation or vomiting < or =15 min after supplementation was observed more frequently among children in the zinc group than among those in the placebo group during the supplementation period (37% compared with 13%; odds ratio: 0.25; 95% CI: 0.20, 0.30).

CONCLUSION

Adjuvant treatment with zinc neither reduced the risk of treatment failure nor accelerated recovery in episodes of nonsevere or severe pneumonia. This trial was registered at clinicaltrials.gov as NCT00148733.

Clinical presentation and severity of viral community-acquired pneumonia in young Nepalese children

BACKGROUND

Most deaths from pneumonia in children <5 years of age occur in developing countries, where information about the clinical impact and severity of viral causes of respiratory infections is limited.

METHODS

From June 29, 2004 to June 30, 2007 we evaluated 2230 cases of pneumonia (World Health Organization criteria) in children aged 2 to 35 months in Bhaktapur, Nepal. A nasopharyngeal aspirate from each case was examined for 7 respiratory viruses using reverse-transcription polymerase chain reaction. We compared illness duration, severity, and treatment failure between cases positive and negative for the individual viruses in multiple regression models.

RESULTS

A total of 2219 cases had a valid polymerase chain reaction result and were included in the analyses. Overall, 46.1% of cases were 2 to 11 months of age. Being infected with respiratory syncytial virus (RSV) was associated with lower chest indrawing (odds ratio [OR] 2.17; 95% confidence interval [CI] 1.42-3.30) and, among infants, oxygen saturation <93% (OR: 1.88; CI: 1.32-2.69). Among the 2088 nonsevere pneumonia cases, those positive for RSV had a longer time to recovery (hazard ratio 0.82; CI 0.75-0.90; P < 0.001) and an increased risk of treatment failure (OR: 1.75; CI: 1.34-2.28; P < 0.001) than the RSV negative cases.

CONCLUSIONS

Being infected with RSV was associated with a more severe clinical presentation of pneumonia, longer illness duration, and increased risk of treatment failure. The severity of RSV infection was age related, infants being more severely affected.