Viral etiology of acute respiratory infections among children in Porto Alegre, RS, Brazil

Low circulation of Influenza A and coinfection with SARS-CoV-2 among other respiratory viruses during the COVID-19 pandemic in a region of southern Brazil

With the arrival of coronavirus disease 2019 (COVID-19) in Brazil in February 2020, several preventive measures were taken by the population aiming to avoid severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection including the use of masks, social distancing, and frequent hand washing then, these measures may have contributed to preventing infection also by other respiratory viruses. Our goal was to determine the frequencies of Influenza A and B viruses (FLUAV/FLUBV), human mastadenovirus C (HAdV-C), Enterovirus 68 (EV-68), and rhinovirus (RV) besides SARS-CoV-2 among hospitalized patients suspect of COVID-19 with cases of acute respiratory disease syndrome (ARDS) in the period of March to December 2020 and to detect possible coinfections among them. Nucleic acid detection was performed using reverse-transcription quantitative polymerase chain reaction (RT-qPCR) in respiratory samples using naso-oropharyngeal swabs and bronchoalveolar lavage. A total of 418 samples of the 987 analyzed (42.3%) were positive for SARS-CoV-2, 16 (1.62%) samples were positive for FLUAV, no sample was positive for FLUBV or EV-68, 67 (6.78%) samples were positive for HAdV-C, 55 samples were positive for RV 1/2 (26.3%) and 37 for RV 2/2 (13.6%). Coinfections were also detected, including a triple coinfection with SARS-CoV-2, FLUAV, and HAdV-C. In the present work, a very low frequency of FLUV was reported among hospitalized patients with ARDS compared to the past years, probably due to preventive measures taken to avoid COVID-19 and the high influenza vaccination coverage in the region in which this study was performed.

Seasonality, molecular epidemiology, and virulence of Respiratory Syncytial Virus (RSV): A perspective into the Brazilian Influenza Surveillance Program

Background

Respiratory Syncytial Virus (RSV) is the main cause of pediatric morbidity and mortality. The complex evolution of RSV creates a need for worldwide surveillance, which may assist in the understanding of multiple viral aspects.

Objectives

This study aimed to investigate RSV features under the Brazilian Influenza Surveillance Program, evaluating the role of viral load and genetic diversity in disease severity and the influence of climatic factors in viral seasonality.

Methodology

We have investigated the prevalence of RSV in children up to 3 years of age with severe acute respiratory infection (SARI) in the state of Espirito Santo (ES), Brazil, from 2016 to 2018. RT-qPCR allowed for viral detection and viral load quantification, to evaluate association with clinical features and mapping of local viral seasonality. Gene G sequencing and phylogenetic reconstruction demonstrated local genetic diversity.

Results

Of 632 evaluated cases, 56% were caused by RSV, with both subtypes A and B co-circulating throughout the years. A discrete inverse association between average temperature and viral circulation was observed. No correlation between viral load and disease severity was observed, but children infected with RSV-A presented a higher clinical severity score (CSS), stayed longer in the hospital, and required intensive care, and ventilatory support more frequently than those infected by RSV-B. Regarding RSV diversity, some local genetic groups were observed within the main genotypes circulation RSV-A ON1 and RSV-B BA, with strains showing modifications in the G gene amino acid chain.

Conclusion

Local RSV studies using the Brazilian Influenza Surveillance Program are relevant as they can bring useful information to the global RSV surveillance. Understanding seasonality, virulence, and genetic diversity can aid in the development and suitability of antiviral drugs, vaccines, and assist in the administration of prophylactic strategies.

Epidemiology and factors associated with the severity of viral acute lower respiratory infection in children hospitalized in Manaus, Amazonas, in 2017-2018: An observational study

ABSTRACT

To investigate the epidemiology and factors associated with the severity of viral acute lower respiratory infection (ALRI) in children hospitalized in Manaus, Amazonas, in 2017 to 2018.Retrospective cohort study of children hospitalized at the Hospital and Emergency Room Delphina Rinaldi Abdel Aziz, in Manaus, from April 01, 2017 to August 31, 2018, with a clinical diagnosis of ALRI and nasopharyngeal aspirates positive for at least 1 respiratory virus.One hundred forty-six children aged 0.2 to 66 months (median 7 months) were included. Patients were divided into 2 groups according to the disease severity classified by an adapted Walsh et al score: moderate disease, score 0-4, n = 66 (45.2%) and severe disease, score 5-7, n = 80 (54.8%). A greater number of viral ALRI cases were observed in the rainiest months. Respiratory syncytial virus was the most prevalent (n = 103, 70.3%), followed by metapneumovirus (n = 24, 16.4%), influenza virus (n = 17, 11.6%), parainfluenza virus (n = 11, 7.5%), and adenovirus (n = 4, 2.7%). Co-detections of 2 to 3 viruses were found in 12 (8.2%) patients. The presence of viral coinfection was an independent risk factor for disease severity (adjusted relative risk [RR] 1.53; 95% CI 1.10-2.14). Twelve patients (8.2%) died, all with severe disease. Risk factors for death were shock (adjusted RR 10.09; 95% CI 2.31-43.90) and need for vasoactive drugs (adjusted RR 10.63; 95% CI 2.44-46.31).There was a higher incidence of viral ALRI in Manaus in the rainy season. Respiratory syncytial virus was the most prevalent virus. The presence of viral coinfection was an independent risk factor for disease severity.

Respiratory viral infections in hospitalised paediatric patients in the tropics

AIM

Respiratory viruses are a huge disease burden globally. An understanding of the seasonal trends and the ability to predict peak periods of respiratory virus disease incidence is useful for clinical care.

METHODS

This is a retrospective analysis of paediatric hospitalizations of laboratory-confirmed viral respiratory tract infections in KK Women's and Children's Hospital, Singapore, from 1 January 2011 to 31 December 2016. Standard direct immunofluorescence was used to detect respiratory syncytial virus (RSV), influenza A and B viruses, parainfluenza 1, 2 and 3 viruses, metapneumovirus and adenovirus.

RESULTS

A total of 97 840 specimens were analysed with a positive detection rate of 23.8%. RSV made up the largest proportion (42% of the total positive results), predominating between May to September. Influenza A had two peaks, June to July and December to January. Type 3 was the most common parainfluenza virus and showed annually recurring peaks. In contrast, parainfluenza 1 and 2, metapneumovirus and adenovirus had a biennial pattern. The test of seasonality detected identifiable seasonality for RSV and parainfluenza 3 virus.

CONCLUSIONS

In conclusion, respiratory viruses have different and overlapping seasonality in tropical Singapore. Respiratory virus testing for patients admitted for acute respiratory infection is useful to target antiviral therapies and appropriate infection control practices.

Epidemiology of influenza B infection in the state of Rio Grande do Sul, Brazil, from 2003 to 2019

Influenza B virus (IBV) causes respiratory tract infections with mild, moderate, or life-threatening symptoms. This study describes the epidemiology of IBV infection in Rio Grande do Sul (RS), Brazil, over 17 years. Nasopharyngeal samples were collected from outpatients presenting acute respiratory illness (ARI) between 2003 and 2019, and from inpatients with severe acute respiratory infection (SARI) from 2009 to 2019. IBV was detected by immunofluorescence assay or quantitative real-time polymerase chain reaction; demographic and clinical data were analyzed. In total, 48,656 cases of respiratory infection were analyzed, of which 20.45% were ARI, and 79.46% were SARI. Respiratory viruses accounted for 22.59% and 37.47% of the cases of ARI and SARI, respectively. Considering respiratory viral infections, 17.10% of ARI and 3.06% of SARI were associated with IBV. IBV circulated year-round in RS, with an increase in autumn and winter, peaking in July (p = .005). IBV infection showed an association with age, and most outpatients positive for IBV were between 10 and 49 years old, whereas IBV infection in SARI affected mainly individuals ≤ 1 year or ≥ 60 years old. No significant association was found between sex and IBV infection. Coryza, sore throat, and myalgia were associated with ARI (p < .001). Moreover, 3.18% of the deaths associated with respiratory virus infection were positive for IBV; notably, cardiopathy (p < .001), metabolic disease (p < .001), and smoking (p = .003) were associated to fatality in IBV infection. IBV is an important cause of severe respiratory infections, and the fatality risk is high in individuals with cardiopathy and metabolic diseases.

Synthetic Compounds with 2-Amino-1,3,4-Thiadiazole Moiety Against Viral Infections

Viral infections have resulted in millions of victims in human history. Although great efforts have been made to find effective medication, there are still no drugs that truly cure viral infections. There are currently approximately 90 drugs approved for the treatment of human viral infections. As resistance toward available antiviral drugs has become a global threat to health, there is an intrinsic need to identify new scaffolds that are useful in discovering innovative, less toxic and highly active antiviral agents. 1,3,4-Thiadiazole derivatives have been extensively studied due to their pharmacological profile, physicochemical and pharmacokinetic properties. This review provides an overview of the various synthetic compounds containing the 2-amino-1,3,4-thiadiazole moiety that has been evaluated for antiviral activity against several viral strains and could be considered possible prototypes for the development of new antiviral drugs.

TEMPORAL TREND OF HOSPITALIZATIONS FOR ACUTE BRONCHIOLITIS IN INFANTS UNDER ONE YEAR OF AGE IN BRAZIL BETWEEN 2008 AND 2015

OBJECTIVE

To evaluate the trend of hospitalization for acute bronchiolitis in infants under one year of age, in the past eight years and after the implementation of the palivizumab immunization program in Brazil.

METHODS

The study is a retrospective analysis of data on infants younger than one year of age, who were hospitalized with acute bronchiolitis between 2008 and 2015 in Brazil. The Brazilian National Health System database was used. The rates of hospitalization in the pre-implementation (2008-2012) and post-implementation (2014-2015) periods of the palivizumab immunization program were evaluated. The total number of admissions in the same period was used as a comparison.

RESULTS

Between January 2008 and December 2015, 263,679 hospitalizations for bronchiolitis were recorded in infants younger than one year of age, 60% represented by boys. The incidence of hospitalization for bronchiolitis increased by 49% over this period (8.5 to 12.7 per 1,000 inhabitants per year). Between 2013 and 2014, the incidence rate of hospitalization for acute bronchiolitis decreased by 8% (12.5 to 11.5 per 1,000 inhabitants per year). However, in the second year of the program, hospitalization rate increased again by 10% (12.7 per 1,000 inhabitants per years).

CONCLUSIONS

Acute bronchiolitis presented increasing rates of hospitalization over the study period. Hospitalization incidence for acute bronchiolitis declined one year after the implementation of palivizumab but increased again in the second year of the program.

A 28-year study of human parainfluenza in Rio Grande do Sul, Southern Brazil

PROBLEM

Human parainfluenza virus (hPIV) is an important pathogen in respiratory infections, however the health burden of hPIV is underestimated. This study describes the infections by hPIV1-3 in Rio Grande do Sul, Brazil, from 1990 to 2017, providing data of the frequency and seasonality of cases and associated clinical symptoms.

METHOD OF STUDY

Nasopharyngeal samples of patients with respiratory infection were collected, clinical data were analyzed, and immunofluorescence was used to detect hPIV.

RESULTS

Respiratory viruses were detected in 33.63% of respiratory infections. In a total of 11 606 cases of viral respiratory infection, 781 were positive for hPIV; hPIV prevalence ranged from 2.14% to 27% of viral respiratory infections. hPIV1 circulates mainly during fall; hPIV3 circulation, in turn, starts in fall and peaks during spring; and cases of hPIV2 are reported along the year, with peaks in fall and early spring. The most affected age group was children, with hPIV prevalence of 74.23% in patients for less than 1 year. A higher proportion of girls were infected than boys, however, no difference by sex was observed considering all age groups. The most frequent type was hPIV3, especially in hospitalized patients. Both hPIV1 and 3 were associated with dyspnea, while hPIV2 caused mild symptoms mainly in nonhospitalized patients. Nineteen fatalities occurred, 89.5% of them associated with risk factors (prematurity; chronic diseases; age, <1 or >60 years).

CONCLUSION

hPIV causes a high number of respiratory infections, leading to hospitalization especially in children; epidemiological and surveillance studies are important for the control and management of respiratory infections.

Prevalence and determinants of Acute Lower Respiratory Infections among children under-five years in sub-Saharan Africa: Evidence from demographic and health surveys

Acute Lower Respiratory Infections (ALRIs) account for 5.8 million deaths globally and 50% of these deaths occur in sub-Saharan Africa. In this paper, we examined the prevalence and determinants of ALRIs among children under-five years in 28 sub–Saharan African countries. We used data from the most recent (2011–2016) Demographic and Health Surveys of the 28 countries. Women aged 15–49 (N = 13,495) with children under-five years participated in the study. Data were extracted and analysed using STATA version 14.2. Bivariate and multivariate analyses were done to establish associations between the outcome and explanatory variables. The prevalence of ALRI for all the countries was 25.3%. Congo (39.8%), Gabon (38.1%), Lesotho (35.2%), and Tanzania (35.2%) were the countries with the highest prevalence of ALRIs. The results from the multivariate analyses showed that children aged 24–59 months (AOR = 1.15; 95% CI = 1.04–1.28), and children who received intestinal parasite in the 6 months preceding the survey (AOR = 1.11; 95% CI = 1.02–1.22) had higher odds of developing ALRIs. However, children whose mothers were employed (AOR = 0.77; 95% CI = 0.64–0.94) and those whose households used improved toilet facilities (AOR = 0.72; 95% CI = 0.64–0.97) had lower odds of contracting ALRIs. Our findings underscore the need for stakeholders in health in the various sub-Saharan African countries, especially those worst affected by ALRIs to implement programmes and develop policies at different levels aimed at reducing infections among children under-five years. Such strategies should specifically focus on improving the administration of medications for intestinal worms, health education to mothers with children under five on ALRIs and improving the sanitation situations of households through the provision of improved toilet facilities.

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We examined the prevalence and determinants of Acute Lower Respiratory Infections (ALRIs) among children under-five years in sub–Sahara Africa.

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ALRIs account for 5.8 million deaths globally.

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The prevalence of ALRI is 25.3% in sub-Sahara Africa.

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Children aged 24–59 months had higher odds of developing ALRIs.

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Employed mothers and improved toilet facility are protective factors against ALRIs.

Incidence and seasonality of respiratory viruses causing acute respiratory infections in the Northern United Arab Emirates

Background

The data on the seasonality of respiratory viruses helps to ensure the optimal vaccination period and to monitor the possible outbreaks of variant type.

Objectives

This study was designed to describe the molecular epidemiology and seasonality of acute respiratory infection (ARI)‐related respiratory viruses in the United Arab Emirates (UAE).

Methods

Both upper and lower respiratory specimens were collected for the analysis from all the patients who visited the Sheikh Khalifa Specialty Hospital (SKSH) with ARI for over 2 years. The multiplex real‐time reverse transcription polymerase chain reaction (rRT‐PCR) test was used to detect respiratory viruses, which include human adenovirus, influenza virus (FLU) A and B, respiratory syncytial virus, parainfluenza viruses, human rhinovirus (HRV), human metapneumovirus, human enterovirus, human coronavirus, and human bocavirus.

Results

A total of 1,362 respiratory samples were collected from 733 (53.8%) male and 629 (46.2%) female patients with ARI who visited the SKSH between November 2015 and February 2018. The rRT‐PCR test revealed an overall positivity rate of 37.2% (507/1362). The positive rate increased during winter; it was highest in December and lowest in September. FLU was the most frequently detected virus (273/1362 [20.0%]), followed by human rhinovirus (146/1362 [10.7%]). The FLU positivity rate showed two peaks, which occurred in August and December. The peak‐to‐low ratio for FLU was 2.26 (95% confidence interval: 1.52‐3.35).

Conclusions

The pattern of FLU in the UAE parallels to that of temperate countries. The trend of the small peak of FLU in the summer suggests a possibility of semi‐seasonal pattern in the UAE.

Effects of air pollutants on occurrences of influenza-like illness and laboratory-confirmed influenza in Hefei, China

Accumulating evidence suggests that air pollution is a risk factor for adverse respiratory and cardiovascular health outcomes. However, the different impacts of exposure to air pollutants on influenza virus activity and influenza-like illness (ILI) have not been well documented in epidemiological studies. We examined the association between air pollutants of particular matters < 2.5 μm (PM_2.5), particular matters < 10 μm (PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and influenza occurrences in Hefei, China, from December 2013 to December 2015 by generalized Poisson additive regression models. The result suggested that PM_2.5 and PM₁₀ had similar effects on clinical ILI and influenza incidence. PM₁₀ was negatively associated with clinical ILI (relative risk (RR) 0.980, 95% confidence interval (CI) 0.974-0.987), while PM_2.5 were positively associated with clinical ILI (RR 1.040; 95% CI 1.032-1.049). RRs for the laboratory-confirmed cases of influenza were 0.813 (95% CI, 0.755-0.875) for PM₁₀ and 1.216 (95% CI, 1.134-1.304) for PM_2.5. Nevertheless, the impacts of SO₂ and NO₂ on ILI and influenza were distinct. SO₂ had significant influence on laboratory-confirmed influenza and had no significant linear relationship with ILI. NO₂ was negatively correlated with influenza but had no obvious effect on clinical ILI cases. The present study contributes novel evidence on understanding of the effects of various air pollutants on influenza activities, and these findings can be useful and important for the development of influenza surveillance and early warning systems.

Seasonality of respiratory viruses causing hospitalizations for acute respiratory infections in children in Nha Trang, Vietnam

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Hospitalizations for respiratory viruses are seasonal in Vietnam

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Respiratory syncytial virus peaks in the late summer months, and inuenza A in April to June

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No clear seasonality is seen for human rhinovirus

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Human parainuenza 3 and human rhinovirus are positively associated with dew point

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This work can inform the timing of inuenza and RSV vaccination and the judicious use of antibiotics in Vietnam

Background

Acute respiratory infections (ARIs) are the most common causes of death in children under 5 years of age. While the etiology of most pneumonia and ARI episodes is undiagnosed, a broad range of ARI-causing viruses circulate widely in South East Asia. However, the patterns and drivers of the seasonal transmission dynamics are largely unknown. Here we identify the seasonal patterns of multiple circulating viruses associated with hospitalizations for ARIs in Nha Trang, Vietnam.

Methods

Hospital based enhanced surveillance of childhood ARI is ongoing at Khanh Hoa General Hospital in Nha Trang. RT-PCR was performed to detect 13 respiratory viruses in nasopharyngeal samples from enrolled patients. Seasonal patterns of childhood ARI hospital admissions of various viruses were assessed, as well as their association with rainfall, temperature, and dew point.

Results

Respiratory syncytial virus peaks in the late summer months, and influenza A in April to June. We find significant associations between detection of human parainfluenza 3 and human rhinovirus with the month's mean dew point. Using a cross-wavelet transform we find a significant out-of-phase relationship between human parainfluenza 3 and temperature and dew point.

Conclusions

Our results are important for understanding the temporal risk associated with circulating pathogens in Southern Central Vietnam. Specifically, our results can inform timing of routing seasonal influenza vaccination and for when observed respiratory illness is likely viral, leading to judicious use of antibiotics in the region.

Meteorological factors and respiratory syncytial virus seasonality in subtropical Australia

Evidence is emerging regarding the influence of meteorological factors on seasonal respiratory syncytial virus outbreaks. Data however, are limited for subtropical regions, especially in the southern hemisphere. We examined whether meteorological data (daily minimum and maximum temperatures, rainfall, relative humidity, dew point, daily global solar exposure) and tourist numbers were associated with the incidence of RSV in children aged <5 years for the Gold Coast region of South-East Queensland, Australia (latitude 28.0°S). RSV cases between 1 July 2007 and 30 June 2016 were identified from the Pathology Queensland Gold Coast Laboratory database. Time-series methods were used to identify seasonal patterns. RSV activity peaked in mid-to-late autumn (April–May), tapering in winter (June–August). While most meteorological variables measured were associated with RSV incidence, rainfall (ρ = 0.40, 95% confidence interval (CI) 0.32–0.48) and humidity (ρ = 0.38, 95% CI 0.29–0.46) 8 weeks earlier had the nearest temporal relationship. Tourist numbers were not correlated with RSV activity. Identifying meteorological conditions associated with seasonal RSV epidemics can improve understanding of virus transmission and assist planning for their impact upon the health sector, including timing of passive RSV immunoprophylaxis for high-risk infants and future public health interventions, such as maternal immunisation with RSV vaccines.

Spatiotemporal dynamics of influenza A(H1N1)pdm09 in Brazil during the pandemic and post-pandemic periods

Influenza A(H1N1)pdm09 was responsible for the first global flu pandemic in 21st century affecting all the world. In Brazil, A(H1N1)pdm09 is still circulating as a seasonal virus, causing deaths every year. Nevertheless, the viral diffusion process that yearly seeds new influenza strains in the country was not investigated yet. The aim of the current study was to describe the phylodynamics and phylogeography of influenza A(H1N1)pdm09 in Brazil between 2009 and 2014. Neuraminidase sequences from Brazil and other regions of the World were retrieved and analyzed. Bayesian phylogeographic and phylodynamic model approaches were used to reconstruct the spatiotemporal and demographic history of influenza A(H1N1)pdm09 in Brazil (divided in subtropical and tropical regions) and related countries. Our analyses reveal that new influenza A(H1N1)pdm09 lineages are seeded in Brazil in almost each year and the main sources of viral diversity are North America, Europe and East Asia. The phylogeographic asymmetric model also revealed that Brazil, mainly the subtropical region, seeds viral lineages into other countries. Coalescent analysis of the compiled dataset reconstructed the peak of viral transmissions in the winter months of Southern hemisphere. The results presented in this study can be informative to public health, guide intervention strategies and in the understanding of flu virus migration, which helps to predict antigenic drift and consequently the developing of new vaccines.

Respiratory syncytial virus seasonality in Brazil: implications for the immunisation policy for at-risk populations

Respiratory syncytial virus (RSV) infection is the leading cause of hospitalisation for respiratory diseases among children under 5 years old. The aim of this study was to analyse RSV seasonality in the five distinct regions of Brazil using time series analysis (wavelet and Fourier series) of the following indicators: monthly positivity of the immunofluorescence reaction for RSV identified by virologic surveillance system, and rate of hospitalisations per bronchiolitis and pneumonia due to RSV in children under 5 years old (codes CID-10 J12.1, J20.5, J21.0 and J21.9). A total of 12,501 samples with 11.6% positivity for RSV (95% confidence interval 11 - 12.2), varying between 7.1 and 21.4% in the five Brazilian regions, was analysed. A strong trend for annual cycles with a stable stationary pattern in the five regions was identified through wavelet analysis of the indicators. The timing of RSV activity by Fourier analysis was similar between the two indicators analysed and showed regional differences. This study reinforces the importance of adjusting the immunisation period for high risk population with the monoclonal antibody palivizumab taking into account regional differences in seasonality of RSV.

Epidemiology and Clinical Characteristics of Respiratory Infections Due to Adenovirus in Children Living in Milan, Italy, during 2013 and 2014

To evaluate the predominant human adenovirus (HAdV) species and types associated with pediatric respiratory infections, nasopharyngeal swabs were collected from otherwise healthy children attending an emergency room in Milan, Italy, due to a respiratory tract infection from January 1 to February 28 of two subsequent years, 2013 and 2014. The HAdVs were detected using a respiratory virus panel fast assay (xTAG RVP FAST v2) and with a HAdV-specific real-time polymerase chain reaction; their nucleotides were sequenced, and they were tested for positive selection. Among 307 nasopharyngeal samples, 61 (19.9%) tested positive for HAdV. HAdV was the only virus detected in 31/61 (50.8%) cases, whereas it was found in association with one other virus in 25 (41.0%) cases and with two or more viruses in 5 (8.2%) cases. Human Enterovirus/human rhinovirus and respiratory syncytial virus were the most common co-infecting viral agents and were found in 12 (19.7%) and 7 (11.5%) samples, respectively. Overall, the HAdV strain sequences analyzed were highly conserved. In comparison to HAdV-negative children, those infected with HAdV had a reduced frequency of lower respiratory tract involvement (36.1% vs 55.2%; p = 0.007), wheezing (0.0% vs 12.5%; p = 0.004), and hospitalization (27.9% vs 56.1%; p<0.001). Antibiotic therapy and white blood cell counts were more frequently prescribed (91.9% vs 57.1%; p = 0.04) and higher (17,244 ± 7,737 vs 9,565 ± 3,211 cells/μL; p = 0.04), respectively, in children infected by HAdV-C than among those infected by HAdV-B. On the contrary, those infected by HAdV-B had more frequently lower respiratory tract involvement (57.1% vs 29.7%) but difference did not reach statistical significant (p = 0.21). Children with high viral load were absent from child care attendance for a longer period of time (14.5 ± 7.5 vs 5.5 ± 3.2 days; p = 0.002) and had higher C reactive protein levels (41.3 ± 78.5 vs 5.4 ± 9.6 μg/dL; p = 0.03). This study has shown that HAdV infections are diagnosed more commonly than usually thought and that HAdVs are stable infectious agents that do not frequently cause severe diseases. A trend toward more complex disease in cases due to HAdV species C and in those with higher viral load was demonstrated. However, further studies are needed to clarify factors contributing to disease severity to understand how to develop adequate preventive and therapeutic measures.

Relative frequency, Possible Risk Factors, Viral Codetection Rates, and Seasonality of Respiratory Syncytial Virus Among Children With Lower Respiratory Tract Infection in Northeastern Brazil

Few studies, each limited to a single major city, have investigated the prevalence and seasonal patterns of different viruses among children with low respiratory tract infections (LRTI) in Northeastern Brazil. The aim of this study was to determine the frequency of respiratory syncytial virus (RSV) and of 7 other viruses in children for LRTI in 4 capitals from this region, and investigate their association with several risk factors, including meteorological data. From April 2012 to March 2013, 507 children, aged up to 24 months and hospitalized with LRTI in one of the participating centers at Aracajú, Salvador, Recife, and Maceió, had a sample of nasopharyngeal aspirate collected and analyzed for the following viruses by reverse-transcription polymerase chain reaction followed by hybridization on low-density microarrays: RSV, influenza, parainfluenza, adenovirus, rhinovirus, metapneumovirus, bocavirus, and coronavirus. The result was positive in 66.5% of cases, RSV was the most common virus (40.2%). Except for rhinovirus (17%), all other virus had frequency rates lower than 6%. Viral coinfections were detected in 13.8% of samples. Possible related risk factors for RSV infection were low age upon entry, attendance of daycare, low gestational age, and low educational level of the father. The relative frequency of viral infections was associated with increasing temperature and decreasing humidity separately, but the results also suggested both associated with increased frequency of RSV. Some of these findings differ from those reported for other regions in Brazil and may be used to guide policies that address LRTI.

Influenza-like illness in an urban community of Salvador, Brazil: incidence, seasonality and risk factors

BACKGROUND

Our understanding of the epidemiology of influenza is limited in tropical regions, which in turn has hampered identifying optimal region-specific policy to diminish disease burden. Influenza-like illness (ILI) is a clinical diagnosis that can be used as a surrogate for influenza. This study aimed to define the incidence and seasonality of ILI and to assess its association with climatic variables and school calendar in an urban community in the tropical region of Salvador, Brazil.

METHODS

Between 2009 and 2013, we conducted enhanced community-based surveillance for acute febrile illnesses (AFI) among patients ≥ 5 years of age in a slum community emergency unit in Salvador, Brazil. ILI was defined as a measured temperature of ≥ 37.8 °C or reported fever in a patient with cough or sore throat for ≤ 7 days, and negative test results for dengue and leptospirosis. Seasonality was analyzed with a harmonic regression model. Negative binomial regression models were used to correlate ILI incidence with rainfall, temperature, relative humidity and the number of days per month that schools were in session while controlling for seasonality.

RESULTS

There were 2,651 (45.6% of 5,817 AFI patients) ILI cases with a mean annual incidence of 60 cases/1,000 population (95% CI 58-62). Risk of ILI was highest among 5-9 year olds with an annual incidence of 105 cases/1,000 population in 2009. ILI had a clear seasonal pattern with peaks between the 35-40th week of the year. ILI peaks were higher and earlier in 5-9 year olds compared with > 19 year olds. No association was seen between ILI and precipitation, relative humidity or temperature. There was a significant association between the incidence of ILI in children 5-9 years of age and number of scheduled school days per month.

CONCLUSIONS

We identified a significant burden of ILI with distinct seasonality in the Brazilian tropics and highest rates among young school-age children. Seasonal peaks of ILI in children 5-9 years of age were positively associated with the number of school days, indicating that children may play a role in the timing of seasonal influenza transmission.

Parainfluenza virus as a cause of acute respiratory infection in hospitalized children

Background

Human parainfluenza viruses account for a significant proportion of lower respiratory tract infections in children.

Objective

To assess the prevalence of Human parainfluenza viruses as a cause of acute respiratory infection and to compare clinical data for this infection against those of the human respiratory syncytial virus.

Methods

A prospective study in children younger than five years with acute respiratory infection was conducted. Detection of respiratory viruses in nasopharyngeal aspirate samples was performed using the indirect immunofluorescence reaction. Length of hospital stay, age, clinical history and physical exam, clinical diagnoses, and evolution (admission to Intensive Care Unit or general ward, discharge or death) were assessed. Past personal (premature birth and cardiopathy) as well as family (smoking and atopy) medical factors were also assessed.

Results

A total of 585 patients were included with a median age of 7.9 months and median hospital stay of six days. No difference between the HRSV+ and HPIV+ groups was found in terms of age, gender or length of hospital stay. The HRSV+ group had more fever and cough. Need for admission to the Intensive Care Unit was similar for both groups but more deaths were recorded in the HPIV+ group. The occurrence of parainfluenza peaked during the autumn in the first two years of the study.

Conclusion

Parainfluenza was responsible for significant morbidity, proving to be the second-most prevalent viral agent in this population after respiratory syncytial virus. No difference in clinical presentation was found between the two groups, but mortality was higher in the HPIV+ group.

[Application of molecular assay for adenovirus detection among different pediatric patients]

OBJECTIVE:

Adenoviruses play an important role in the etiology of severe acute lower respiratory infection, especially in young children. The aim of the present study was to evaluate the Human Adenovirus (HAdV) detection by different methods (Direct Fluorescence Assay DFA and Nested Polymerase Chain Reaction nested PCR), among samples collected from different groups of pediatric patients.

METHODS:

Collection of samples was made in children with congenital heart disease (CHD 123 nasal aspirates collected in the years of 2005, 2007 and 2008) and in community children (CC 165 nasal aspirates collected in 2008). Children were eligible if they presented acute respiratory infection (ARI) of probable viral etiology, within up to 7 days of symptoms' onset. All studied samples were evaluated by DFA and nested PCR assay.

RESULTS:

Of the 290 samples included during the study period, 43 (14.8%) were positive on at least one test: 17/165 (10.3%) of the CC and 26/125 (20.8%) of the CHD children. The nested PCR detection rates in the community children were 15/165 (9.1%), and for children with CHD, 24/125 (19.2%). Molecular method showed higher detection rates when compared to the DFA test (p<0.001). Univariate analysis showed that children with congenital heart disease presented a significantly higher chance for acquiring the HAdV (Odds Ratio 2.3; 95% CI: 1.18-4.43).

CONCLUSIONS:

Based on data obtained in the present evaluation, we suggest that a routine surveillance should be performed in high risk patients by molecular methods, thus improving diagnostic flow and efficiency.

Respiratory viruses are continuously detected in children with chronic tonsillitis throughout the year

OBJECTIVE

To evaluate the oscillations on the viral detection in adenotonsillar tissues from patients with chronic adenotonsillar diseases as an indicia of the presence of persistent viral infections or acute subclinical infections.

STUDY DESIGN

Cross-sectional prospective study.

SETTING

Tertiary hospital.

METHODS

The fluctuations of respiratory virus detection were compared to the major climatic variables during a two-year period using adenoids and palatine tonsils from 172 children with adenotonsillar hypertrophy and clinical evidence of obstructive sleep apnoea syndrome or recurrent adenotonsillitis, without symptoms of acute respiratory infection (ARI), by TaqMan real-time PCR.

RESULTS

The rate of detection of at least one respiratory virus in adenotonsillar tissue was 87%. The most frequently detected viruses were human adenovirus in 52.8%, human enterovirus in 47.2%, human rhinovirus in 33.8%, human bocavirus in 31.1%, human metapneumovirus in 18.3% and human respiratory syncytial virus in 17.2%. Although increased detection of human enterovirus occurred in summer/autumn months, and there were summer nadirs of human respiratory syncytial virus in both years of the study, there was no obvious viral seasonality in contrast to reports with ARI patients in many regions of the world.

CONCLUSION

Respiratory viruses are continuously highly detected during whole year, and without any clinical symptomatology, indicating that viral genome of some virus can persist in lymphoepithelial tissues of the upper respiratory tract.

Viral etiology and seasonality of influenza-like illness in Gabon, March 2010 to June 2011

Background

Surveillance of influenza-like illness (ILI) in Central Africa began only recently, and few data are therefore available on the circulation of influenza virus and other respiratory viruses. In Gabon, a Central African country, we established a surveillance network in four major towns in order to analyze cases of ILI among patients who visited health centers between March 2010 and June 2011, and to determine the viral etiology.

Methods

Nasal swabs were sent for analysis to the Centre International de Recherches Médicales de Franceville, where they were screened for 17 respiratory viruses in a multiplex real-time reverse transcription polymerase chain reaction for all pathogens according the following pairs: adenovirus/parainfluenza virus 4, respiratory syncytial virus/human metapneumovirus, parainfluenza virus 1/parainfluenza virus 2, pandemic influenza virus A/seasonal influenza virus A (H1N1, H3N2)/seasonal influenza virus B, human coronaviruses 229E/OC43, human coronaviruses NL63/HKU1, rhinovirus/human parechovirus, and enterovirus/parainfluenza virus 3.

Results

We analyzed a total of 1041 specimens, of which 639 (61%) were positive for at least one virus. Three-quarters of the patients were children under five years old. We therefore focused on this age group, in which 68.1% of patients were positive for at least one virus. The most common viruses were adenoviruses (17.5%), followed by parainfluenza viruses (PIVs) 1–4 (16.8%), enteroviruses (EV) (14.7%), respiratory syncytial virus (RSV) (13.5%), and influenza virus (11.9%). The prevalence of some viruses was subject to geographic and seasonal variations. One-third of positive samples contained more than one virus.

Conclusions

Like most studies in the world, the virus PIVs, EV, RSV, Influenza virus, HRV were predominant among children under five years old in Gabon. An exception is made for adenoviruses which have a high prevalence in our study. However adenoviruses can be detected in asymptomatic persons. These finding gave a better knowledge of the circulation and the seasonality of the viruses involved in ILI in Gabon.

Immunohistochemistry analysis of pulmonary infiltrates in necropsy samples of children with non-pandemic lethal respiratory infections (RSV; ADV; PIV1; PIV2; PIV3; FLU A; FLU B)

•

Respiratory infections represent a globally cause of mortality in childhood.

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Individuals with impaired cellular immunity have more severe diseases.

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The inflammatory response appears to play role in recovery from these diseases.

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TCD8+ count (immunohistochemistry) was higher in the viral pneumonias (p  = 0.04).

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Tissue TCD8+ lymphocytes play role in the viral pneumonia inflammatory response.

Background

Acute viral respiratory infections represent a globally important cause of morbidity and mortality in childhood. An individual's cellular response appears to play a critical role in recovery from infections, given that individuals with impaired cellular immunity, congenital or acquired, have more severe diseases and secrete the virus for longer periods.

Objectives

The aim of this study was to immunohistochemically evaluate the expression of the cell surface antigens CD4, CD8, CD25, CD14 and CD74, in pneumonic infiltrates in the alveolar septa using paraffin-embedded lung samples from autopsies of immunocompetent children who died of lethal, non-pandemic, severe acute respiratory infections.

Study design

From 794 cases of pediatric autopsies of patients with severe respiratory disease (between 1960 and 2004), 193 cases were selected for this study. To identify subpopulations of inflammatory cells in the alveolar septa, cell surface antigen expression was assessed by immunohistochemistry using the following primary antibodies: anti-CD4, anti-CD8, anti-CD14, anti-CD25 and anti-CD74.

Results

The TCD8+ lymphocyte count was higher in the virus-positive group (p = 0.04) and was also much higher among cases that were positive for more than three viral types (p = 0.016). There were fewer CD14+ cells in cases of AdV (adenovirus) infection (p = 0.002), and there was a predominance of CD74+ cells in the histopathological pattern defined as interstitial pneumonitis (p = 0.037).

Conclusions

The results of this study demonstrate that TCD8+ lymphocytes present in the alveolar septa participate to a greater extent in the response toward viral pneumonia, while CD14+ cell numbers are often reduced in cases of AdV.

Epidemiological aspects of influenza A related to climatic conditions during and after a pandemic period in the city of Salvador, Northeastern Brazil

During the influenza pandemic of 2009, the A(H1N1)pdm09, A/H3N2 seasonal and influenza B viruses were observed to be co-circulating with other respiratory viruses. To observe the epidemiological pattern of the influenza virus between May 2009-August 2011, 467 nasopharyngeal aspirates were collected from children less than five years of age in the city of Salvador. In addition, data on weather conditions were obtained. Indirect immunofluorescence, real-time transcription reverse polymerase chain reaction (RT-PCR), and sequencing assays were performed for influenza virus detection. Of all 467 samples, 34 (7%) specimens were positive for influenza A and of these, viral characterisation identified Flu A/H3N2 in 25/34 (74%) and A(H1N1)pdm09 in 9/34 (26%). Influenza B accounted for a small proportion (0.8%) and the other respiratory viruses for 27.2% (127/467). No deaths were registered and no pattern of seasonality or expected climatic conditions could be established. These observations are important for predicting the evolution of epidemics and in implementing future anti-pandemic measures.

Acute respiratory viral infections in children in Rio de Janeiro and Teresópolis, Brazil

The frequency of viral pathogens causing respiratory infections in children in the cities of Rio de Janeiro and Teresópolis was investigated. Nasal swabs from children with acute respiratory illnesses were collected between March 2006 and October 2007. Specimens were tested for viral detection by conventional (RT)-PCR and/or real time PCR. Of the 205 nasal swabs tested, 64 (31.2%) were positive for at least one of the viral pathogens. Single infections were detected in 56 samples, 50 of those were caused by RNA viruses: 33 samples tested positive for rhinovirus, five for influenza A, five for metapneumovirus, four for coronavirus and, three for respiratory syncytial virus. For the DNA viruses, five samples were positive for bocavirus and one for adenovirus. Co-infections with these viruses were detected in eight samples. Our data demonstrate a high frequency of viral respiratory infections, emphasizing the need for a more accurate diagnosis particularly for the emerging respiratory viruses. The fact that the emerging respiratory viruses were present in 9.2% of the tested samples suggests that these viruses could be important respiratory pathogens in the country.

Burden of influenza in Latin America and the Caribbean: a systematic review and meta-analysis

OBJECTIVE

Influenza causes severe morbidity and mortality. This systematic review aimed to assess the incidence, etiology, and resource usage for influenza in Latin America and the Caribbean.

DESIGN

Meta-analytic systematic review. Arcsine transformations and DerSimonian Laird random effects model were used for meta-analyses.

SETTING

A literature search from 1980 to 2008 in MEDLINE, Cochrane Library, EMBASE, LILACS, Ministries of Health, PAHO, proceedings, reference lists, and consulting experts.

SAMPLE

We identified 1092 references, of which 31 were finally included, in addition to influenza surveillance reports. We also used information from the 10 reports from the collaborative group for epidemiological surveillance of influenza and other respiratory virus (GROG), and information retrieved from the WHO global flu database FLUNET.

MAIN OUTCOME MEASURES

Incidence, percentage of influenza specimens out of the total received by influenza centers and resource-use outcomes.

RESULTS

A total of 483 130 specimens of patients with influenza were analyzed. Meta-analysis showed an annual rate of 36 080 (95%CI 28 550 43 610) influenza-like illness per 100 000 persons-years. The percentage of influenza out of total specimens received by influenza centers ranged between 4.66% and 15.42%, with type A the most prevalent, and A subtype H3 predominating. The mean length of stay at hospital due to influenza ranged between 5.8 12.9 days, total workdays lost due to influenza-like illnesses were 17 150 days, and the mean direct cost of hospitalization was US$575 per laboratory-confirmed influenza case.

CONCLUSIONS

Our data show that seasonal influenza imposes a high morbidity and economic burden to the region. However, the vaccine-uptake rate has been low in this region. Population-based cohort studies are required to improve the knowledge about incidence and resource utilization, which would inform healthcare authorities for decision making.

Etiology and seasonality of viral respiratory infections in rural Honduran children

BACKGROUND

Limited data are available in Honduras that describe the etiology and seasonality of respiratory infections, especially in rural outpatient settings. Better data may lead to improved therapeutic and preventive strategies. The goal of our study was to determine the viral etiology and seasonality of acute respiratory infections in a rural Honduran population of children.

METHODS

Prospective clinic surveillance was conducted to identify children < 5 years of age presenting with respiratory symptoms of < 5 days duration. We obtained data on age, sex, medical history, breastfeeding history, symptoms, risk factors, household setting, temperature, respiratory rate and chest examination findings. To assess the association between specific viruses and weather, regional meteorological data were collected. Nasopharyngeal samples were tested for 16 respiratory viruses using a multiplex polymerase chain reaction panel.

RESULTS

From February 2010 through June 2011, 345 children < 5 years of age were enrolled; 17%, 23%, 30% and 31% were <6, 6-11, 12-23 and 24-60 months old, respectively. Including all clinics in the region, 44.5% of patients < 5 years of age with documented respiratory diagnoses were enrolled. At least 1 virus was identified in 75.4% children, of which 7.5% were coinfections; 13.3% were positive for parainfluenza, 11.9% for influenza, 8.1% for human metapneumovirus and 7.5% for respiratory syncytial virus. Rainfall correlated with parainfluenza (P < 0.0001), influenza (P < 0.0001), human metapneumovirus (P = 0.0182) and respiratory syncytial virus (P < 0.0001).

CONCLUSIONS

These results suggest that the spectrum of viruses in ill, rural, Honduran children is similar to that in North and Central America, although the seasonality is typical of some tropical regions.

Adenovirus respiratory tract infections in Peru

Background

Currently, there is a paucity of data regarding human adenovirus (HAdv) circulation in Andean regions of South America. To address this shortcoming, we report the clinical, phylogenetic, and epidemiologic characteristics of HAdv respiratory tract infection from a large sentinel surveillance study conducted among adults and children in Peru.

Methods/Principal Findings

Oropharyngeal swabs were collected from participants visiting any of 38 participating health centers, and viral pathogens were identified by immunofluorescence assay in cell culture. In addition, molecular characterization was performed on 226 randomly selected HAdv samples. Between 2000 and 2010, a total of 26,375 participants with influenza-like illness (ILI) or severe acute respiratory infection (SARI) were enrolled in the study. HAdv infection was identified in 2.5% of cases and represented 6.2% of all viral pathogens. Co-infection with a heterologous virus was found in 15.5% of HAdv cases. HAdv infection was largely confined to children under the age of 15, representing 88.6% of HAdv cases identified. No clinical characteristics were found to significantly distinguish HAdv infection from other respiratory viruses. Geographically, HAdv infections were more common in sites from the arid coastal regions than in the jungle or highland regions. Co-circulation of subgroups B and C was observed each year between 2006 and 2010, but no clear seasonal patterns of transmission were detected.

Conclusions/Significance

HAdv accounted for a significant fraction of those presenting with ILI and SARI in Peru and tended to affect the younger population disproportionately. Longitudinal studies will help better characterize the clinical course of patients with HAdv in Peru, as well as determine the role of co-infections in the evolution of illness.

Human adenovirus infection in children with acute respiratory tract disease in Guangzhou, China

Acute respiratory infections (ARI) are the major worldwide health problem due to associated high morbidity and mortality rates. Adenovirus (Adv) is one of the most common causes of viral ARI, and thus calls for specific diagnosis and better understanding of the epidemiology and clinical characteristics. Our aims were to find out the status of Adv infection in children <14 years with ARI, analyze the epidemiology and clinical characteristics among the Adv‐infected children in Guangzhou, China, and to provide some basis for the research of Adv. The throat and pharyngeal swabs were collected among the children with acute respiratory tract infections in outpatient department from September 2006 to August 2008. The samples were analyzed by PCR and the sequences were blasted with the sequences of Adv in GenBank. Clinical data were analyzed along with virological data by using appropriate statistical methods. Adv was detected in 25 out of 512 (4.9%) children. The genome types of 23 samples were determined after analysis of the gene sequence. The most prevalent Adv type was species B type 3. Among the patients, 10 were of Ad3 (43.5%), three were of Ad1 (1.3%), five were of species C Ad2 (21.7%), and five were of species E Ad4 (21.7%). A higher incidence of positive results was found during the summer season, thus showing a pattern of seasonality. There exists Adv infection in children with acute respiratory system diseases in Guangzhou area. No significant differences were found among different age groups and gender groups. Co‐infections with other respiratory virus were detected in 64% of the Adv positive samples.

Influenza like illness monitoring in adults of the State Capitals and Federal District in Brazil by telephone survey

OBJECTIVES

In order to estimate the prevalence of influenza like illness (ILI) in adults from all state capitals and geographic regions in Brazil, a periodical monitoring of ILI cases by the national telephone survey (VIGITEL) was carried out in 2010.

METHOD

A cross-sectional study with 47,876 telephone interviews in the state capitals and Federal District, a probabilistic sample of adult population (>18 years-old) with landline telephone. Questions concerning the results of ILI cases and pandemic influenza (H1N1) 2009, from January 10 to November 30, were analyzed. The proportion of cases stratified by sociodemographic characteristics and Brazilian geographic region was weighted with data from the National Survey with Household Sampling (PNAD) 2008.

RESULTS

The prevalence of ILI cases in the last 30 days before interview was 31.2% (95%CI 30.2-32.2%) for all state capitals and the Federal District. This prevalence was higher among women, young adults (18 to 29 years-old) and individuals with 9 to 11 years of schooling. According to the geographic region analysis, Northern Brazil presented the highest prevalence of ILI cases. A tendency to increase with further decrease was observed among the geographic regions, except the Northeast. Need for health care assistance was reported by 26.8% (95%CI 25.1-28.5) from ILI cases. Among ILI cases that sought health care assistance, 2.6% (95%CI 1.8-3.4) reported pandemic influenza (H1N1) 2009 medical suspicion.

CONCLUSION

The results of this survey supported influenza surveillance as it provided timeliness and useful surveillance information, which were not captured by the traditional surveillance system, as the occurrence of ILI and need of health care assistance.

Prevalence of and risk factors for wheezing in the first year of life

OBJECTIVE

To determine the prevalence of and the risk factors for wheezing in infants under one year of age and residing in the city of Porto Alegre, Brazil.

METHODS

This was a cross-sectional study and is part of a multicenter, multinational project. The parents or legal guardians of the infants were interviewed at primary health care clinics or during home visits. We used a standardized questionnaire, validated for use in Brazil. Potential risk factors were assessed by means of a Poisson regression model with robust variance estimation, using the Wald test to determine the significance of each variable in the model.

RESULTS

The sample comprised 1,013 infants. The majority of those were male (53%), and the mean age was 13.5 ± 1.2 months. In 61% of the infants, there had been at least one episode of wheezing, which had recurred at least three times in one third of those infants. The mean age at the first episode of wheezing was 5.16 months (median, 5 months). Over 40% of the infants with wheezing visited emergency rooms due to wheezing, and 17% of those were hospitalized at least once in the first year of life because of this symptom. In the multivariate analysis, the risk factors for wheezing were as follows: male gender; history of pneumonia; maternal smoking during pregnancy; day care center attendance; low maternal level of education; early weaning; multiple episodes of cold; first viral infection prior to 3 months of age; existence of siblings; and history of asthma in the nuclear family.

CONCLUSIONS

The prevalence of wheezing is high among infants in the city of Porto Alegre. We identified various risk factors for wheezing in infants.

Pulmonary function in children and adolescents with postinfectious bronchiolitis obliterans

OBJECTIVE

To describe the pulmonary function in children and adolescents with postinfectious bronchiolitis obliterans (PIBO), as well as to evaluate potential risk factors for severe impairment of pulmonary function.

METHODS

The pulmonary function of 77 participants, aged 8-18 years, was assessed by spirometry and plethysmography. The following parameters were analyzed: FVC; FEV1; FEF25-75%; FEV1/FVC; RV; TLC; RV/TLC; intrathoracic gas volume; and specific airway resistance (sRaw). We used Poisson regression to investigate the following potential risk factors for severe impairment of pulmonary function: gender; age at first wheeze; age at diagnosis; family history of asthma; tobacco smoke exposure; length of hospital stay; and duration of mechanical ventilation.

RESULTS

The mean age was 13.5 years. There were pronounced decreases in FEV1 and FEF25-75%, as well as increases in RV and sRaw. These alterations are characteristic of obstructive airway disease. For the parameters that were the most affected, the mean values (percentage of predicted) were as follows: FEV1 = 45.9%; FEF25-75% = 21.5%; RV = 281.1%; RV/TLC = 236.2%; and sRaw = 665.3%. None of the potential risk factors studied showed a significant association with severely impaired pulmonary function.

CONCLUSIONS

The patients with PIBO had a common pattern of severe pulmonary function impairment, characterized by marked airway obstruction and pronounced increases in RV and sRaw. The combination of spirometric and plethysmographic measurements can be more useful for assessing functional damage, as well as in the follow-up of these patients, than are either of these techniques used in isolation. Known risk factors for respiratory diseases do not seem to be associated with severely impaired pulmonary function in PIBO.

Incidence, molecular epidemiology and clinical presentations of human metapneumovirus; assessment of its importance as a diagnostic screening target

BACKGROUND

Human metapneumovirus (HMPV) is a recently discovered human paramyxovirus associated with a spectrum of respiratory symptoms from the common cold to pneumonia and bronchiolitis.

OBJECTIVES

To assess the clinical significance and epidemiology of HMPV, standardized comparison of frequencies of infection, age profiles and disease associations were made with other respiratory viruses in Scotland.

STUDY DESIGN

7091 respiratory samples collected in Scotland between 1 July 2006 and 30 June 2008 from 4282 individuals were screened by multiplex RT-PCR for respiratory syncytial virus (HRSV), adenovirus (AdV), parainfluenza viruses 1-3 (PIV-1, -2 and -3), influenza A and B and by nested RT-PCR for HMPV.

RESULTS

HMPV was the fifth most prevalent virus (2.0% of samples), found predominantly in young children in winter months. In the 2006-2007 respiratory season, 70% of HMPV isolates were genotype A, but a switch to predominantly type B infections occurred next winter. For samples with information on clinical presentations, 26% of HMPV infections were from subjects with lower respiratory tract presentations, lower than recorded for HRSV, but similar to adenovirus, parainfluenza viruses and influenza viruses A and B. Around 13% of HMPV infections were associated with upper respiratory tract symptoms or disease, comparable with other respiratory virus infections.

CONCLUSIONS

Numerically and through its association with respiratory disease, HMPV represents a diagnostically significant target that should be included in PCR-based routine screening of respiratory samples. Understanding the biological basis of observed rapid turnover of HMPV variants, including the observed HMPV genotype change between respiratory seasons requires further longitudinal studies.

Influenza-like illness sentinel surveillance in Peru

Background

Acute respiratory illnesses and influenza-like illnesses (ILI) are a significant source of morbidity and mortality worldwide. Despite the public health importance, little is known about the etiology of these acute respiratory illnesses in many regions of South America. In 2006, the Peruvian Ministry of Health (MoH) and the US Naval Medical Research Center Detachment (NMRCD) initiated a collaboration to characterize the viral agents associated with ILI and to describe the clinical and epidemiological presentation of the affected population.

Methodology/Principal Findings

Patients with ILI (fever ≥38°C and cough or sore throat) were evaluated in clinics and hospitals in 13 Peruvian cities representative of the four main regions of the country. Nasal and oropharyngeal swabs, as well as epidemiological and demographic data, were collected from each patient. During the two years of this study (June 2006 through May 2008), a total of 6,835 patients, with a median age of 13 years, were recruited from 31 clinics and hospitals; 6,308 were enrolled by regular passive surveillance and 527 were enrolled as part of outbreak investigations. At least one respiratory virus was isolated from the specimens of 2,688 (42.6%) patients, with etiologies varying by age and geographical region. Overall the most common viral agents isolated were influenza A virus (25.1%), influenza B virus (9.7%), parainfluenza viruses 1, 2, and 3, (HPIV-1,-2,-3; 3.2%), herpes simplex virus (HSV; 2.6%), and adenoviruses (1.8%). Genetic analyses of influenza virus isolates demonstrated that three lineages of influenza A H1N1, one lineage of influenza A H3N2, and two lineages of influenza B were circulating in Peru during the course of this study.

Conclusions

To our knowledge this is the most comprehensive study to date of the etiologic agents associated with ILI in Peru. These results demonstrate that a wide range of respiratory pathogens are circulating in Peru and this fact needs to be considered by clinicians when treating patients reporting with ILI. Furthermore, these data have implications for influenza vaccine design and implementation in South America.

Prevalence and seasonality of influenza-like illness in children, Nicaragua, 2005-2007

Case rates were high and had marked seasonal peaks.

Although information about seasonality and prevalence of influenza is crucial for development of effective prevention and control strategies, limited data exist on the epidemiology of influenza in tropical countries. To better understand influenza in Nicaragua, we performed a prospective 2-year cohort study of influenza-like illness (ILI) involving 4,276 children, 2–11 years of age, in Managua, during April 2005–April 2007. One peak of ILI activity occurred during 2005, in June–July; 2 peaks occurred during 2006, in June–July and November–December. The rate of ILI was 34.8/100 person-years. A household risk factor survey administered to a subset (61%) of participants identified the following risk factors: young age, asthma, and increasing person density in the household. Influenza virus circulation was confirmed during each ILI peak by laboratory testing of a subset of samples. Our findings demonstrate a high rate of ILI, with seasonal peaks, in children in Nicaragua.

The dilemma of influenza vaccine recommendations when applied to the tropics: the Brazilian case examined under alternative scenarios

Since 1999 the World Health Organization issues annually an additional influenza vaccine composition recommendation. This initiative aimed to extend to the Southern Hemisphere (SH) the benefits-previously enjoyed only by the Northern Hemisphere (NH)--of a vaccine recommendation issued as close as possible to the moment just before the onset of the influenza epidemic season. A short time between the issue of the recommendation and vaccine delivery is needed to maximize the chances of correct matching between putative circulating strains and one of the three strains present in the vaccine composition. Here we compare the effectiveness of the SH influenza vaccination adopted in Brazil with hypothetical alternative scenarios defined by different timings of vaccine delivery and/or composition. Scores were based on the temporal overlap between vaccine-induced protection and circulating strains. Viral data were obtained between 1999 and 2007 from constant surveillance and strain characterization in two Brazilian cities: Belém, located at the Equatorial region, and São Paulo, at the limit between the tropical and subtropical regions. Our results show that, among currently feasible options, the best strategy for Brazil would be to adopt the NH composition and timing, as in such case protection would increase from 30% to 65% (p<.01) if past data can be used as a prediction of the future. The influenza season starts in Brazil (and in the equator virtually ends) well before the SH winter, making the current delivery of the SH vaccination in April too late to be effective. Since Brazil encompasses a large area of the Southern Hemisphere, our results point to the possibility of these conclusions being similarly valid for other tropical regions.

Antigenic and genomic characterization of adenovirus associated to respiratory infections in children living in Northeast Brazil

From January to December 1998, nasopharyngeal aspirates were obtained from 482 children with acute respiratory infections attended in emergence department and wards of a teaching hospital in the city of Salvador, Brazil. The samples were tested for the presence of adenovirus by isolation in tissue culture and indirect immunofluorescence assay. Eleven adenoviruses were detected by both methods in the same clinical samples. Infections by adenovirus were observed during seven months of the year without association with rainy season. Genome analysis was performed on these 11 isolates. Species C was represented by serotypes 1, 2 and 5. Within species B, only serotype 7 (Ad7) was detected. Two genomic variants of Ad1, two variants of Ad2, one of Ad5, and one of Ad7 (7h) were identified. This is the first study of molecular epidemiology of adenovirus associated to acute respiratory infections in children living in Northeast Brazil, and contributes to a better understanding of adenovirus infections in the country.

The epidemiology and antigenic characterization of influenza viruses isolated in Curitiba, South Brazil

Several studies conducted all over the world have reported that the influenza virus is associated with great morbidity and mortality rates. In this study, we analyzed the incidence of the influenza virus between 2000 and 2003 in Curitiba. We studied 1621 samples obtained from outpatients and hospitalized patients of both sexes and all ages. The study was conducted at the local primary care health units (outpatients) and at the tertiary care unit (hospitalized) of the General Hospital of the Federal University in the state of Paraná, Brazil. Nasopharyngeal aspirates and, eventually, bronchoalveolar lavage were assayed for the presence of viral antigens, either by indirect immunofluorescence or cell culture. Of the samples studied, 135 (8.3%) were positive for influenza virus, and of those, 103 (76.3%) were positive for type A and 32 (23.7%) for type B. Additionally, positive samples were analyzed by reverse transcription followed by polymerase chain reaction and subtypes H1 and H3 were identified from this group. A high incidence of positive samples was observed mainly in the months with lower temperatures. Furthermore, outpatients showed a higher incidence of influenza viruses than hospitalized patients.

Molecular epidemiology and disease severity of respiratory syncytial virus in relation to other potential pathogens in children hospitalized with acute respiratory infection in Jordan

Human respiratory syncytial virus (HRSV) is the major viral cause of acute lower respiratory tract infections in children. Few data about the molecular epidemiology of respiratory syncytial virus in developing countries, such as Jordan, are available. The frequency and severity of infections caused by HRSV were assessed in hospitalized Jordanian children <5 years of age compared with other potential etiological agents. Overall a potential pathogen was detected in 78% (254/326) of the children. HRSV was detected in 43% (140/326) of the nasopharyngeal aspirates. HRSV was found more frequently during the winter (January/February), being less frequent or negligible by spring (March/April). Analysis of 135 HRSV‐positive strains using restriction fragment length polymorphism showed that 94 (70%) belonged to subgroup A, and 41 (30%) to subgroup B. There were also two cases of mixed genotypic infection. Only four of the six previously described N genotypes were detected with NP4 predominating. There were no associations between subgroup or N‐genogroup and disease severity. HRSV was significantly associated with more severe acute respiratory infection and the median age of children with HRSV was lower than for those without. Next in order of frequency were adenovirus (116/312: 37%), human bocavirus (57/312: 18%), rhinovirus (36/325: 11%), Chlamydia spp. (14/312: 4.5%), human metapneumovirus (8/326: 2.5%), human coronavirus NL63 (4/325: 1.2%), and influenza A virus (2/323: 0.6%). Influenza B; parainfluenza viruses 1–4, human coronavirus HKU1 and Mycoplasma pneumoniae were not detected. J. Med. Virol. 80:168–174, 2008. © 2007 Wiley‐Liss, Inc.

Effect of climatological factors on respiratory syncytial virus epidemics

Respiratory syncytial virus (RSV) presents as yearly epidemics in temperate climates. We analysed the association of atmospheric conditions to RSV epidemics in San Luis Potosí, S.L.P., Mexico. The weekly number of RSV detections from October 2002 and May 2006 were correlated to ambient temperature, barometric pressure, relative humidity, vapour tension, dew point, precipitation, and hours of light using time-series and regression analyses. Of the variation in RSV cases, 49.8% was explained by the study variables. Of the explained variation in RSV cases, 32.5% was explained by the study week and 17.3% was explained by meteorological variables (average daily temperature, maximum daily temperature, temperature at 08:00 hours, and relative humidity at 08:00 hours). We concluded that atmospheric conditions, particularly temperature, partly explain the year to year variability in RSV activity. Identification of additional factors that affect RSV seasonality may help develop a model to predict the onset of RSV epidemics.

Use of diagnostic algorithms and new technologies to study the incidence and prevalence of viral upper respiratory tract infections and their complications in high risk populations

PURPOSE OF REVIEW

Most studies on the natural history of viral upper respiratory tract infections and their complications rely for ascertainment on self-assessed cold/flu illness or the identification of presumed complications. The criteria for cold/flu definition, however, are variable within and between individuals and illness is not prerequisite for a viral upper respiratory tract infection. These factors bias estimates of the incidence and prevalence of viral upper respiratory tract infections and their complications. Here we review new methodologies that can be adapted for use in future studies to refine those estimates.

RECENT FINDINGS

We present a theoretical basis for standardized assignment of cold/flu episodes using a minimal algorithm template that operates on a structured set of symptoms/signs. We emphasize the greater accuracy of information derived from longitudinal studies that incorporate identification algorithms and assay of nasal secretions for causal virus by polymerase chain reaction and for proinflammatory chemicals to confirm nasal inflammation.

SUMMARY

The methodologies and sampling strategies that we describe hold promise for better characterizing the incidence of complications for symptomatic and asymptomatic expressions of a viral upper respiratory tract infection caused by specific viruses. These data can then be used to estimate the efficacy and efficiency in a specified target population of prophylactic or intercurrent treatments to prevent the complications.

Serodiagnosis of acute respiratory infections in children in Georgia

OBJECTIVE

To investigate the etiology of acute respiratory infections in hospitalized children.

METHODS

A total of 808 children were studied. Investigation of RSV, Adenovirus, Parainfluenza, Influenza A and B, C.trachomatis, C.pneumoniae, M. pneumonia and Legionella were performed with an ELISA for IgM, IgG and IgA antibodies detection.

RESULTS

There were 496 males and 312 females giving a male: female ratio of 1.6:1. Ages range from 1 month to 15 years. The overall detection rate was 57.9%. The most frequently detected were: parainfluenza 12.6%, adenovirus 11.2%, influenza A 7.3%, RSV 6%, M. pneumoniae 5.4%, C.trachomatis 3.5% and mixed-infections 9.2%. Pneumonia was associated most frequently with adenovirus and mixed-infections; wheezing bronchitis--with adenovirus, RSV and M. pneumoniae; bronchitis--with parainfluenza and adenovirus, diseases of upper respiratory tract--with parainfluenza and adenovirus. Peak of the virus activity was during winter (influenza, parainfluenza, adenovirus, RSV) and autumn (parainfluenza, RSV).

CONCLUSION

Viruses are the main causes of ARI in Georgian children. A better understanding of the etiology of ARI in all of the regions of the world may be helpful for timely decision of specific therapy, which can help pediatricians to estimate and manage children with ARI.