Viral respiratory infection in Curitiba, Southern Brazil

Epidemiologic Profile of Severe Acute Respiratory Infection in Brazil During the COVID-19 Pandemic: An Epidemiological Study

Background

The COVID-19 is a significant public health issue, and monitoring confirmed cases and deaths is an essential epidemiologic tool. We evaluated the features in Brazilian hospitalized patients due to severe acute respiratory infection (SARI) during the COVID-19 pandemic in Brazil. We grouped the patients into the following categories: Influenza virus infection (G1), other respiratory viruses' infection (G2), other known etiologic agents (G3), SARS-CoV-2 infection (patients with COVID-19, G4), and undefined etiological agent (G5).

Methods

We performed an epidemiological study using data from DataSUS (https://opendatasus.saude.gov.br/) from December 2019 to October 2021. The dataset included Brazilian hospitalized patients due to SARI. We considered the clinical evolution of the patients with SARI during the COVID-19 pandemic according to the SARI patient groups as the outcome. We performed the multivariate statistical analysis using logistic regression, and we adopted an Alpha error of 0.05.

Results

A total of 2,740,272 patients were hospitalized due to SARI in Brazil, being the São Paulo state responsible for most of the cases [802,367 (29.3%)]. Most of the patients were male (1,495,416; 54.6%), aged between 25 and 60 years (1,269,398; 46.3%), and were White (1,105,123; 49.8%). A total of 1,577,279 (68.3%) patients recovered from SARI, whereas 701,607 (30.4%) died due to SARI, and 30,551 (1.3%) did not have their deaths related to SARI. A major part of the patients was grouped in G4 (1,817,098; 66.3%) and G5 (896,207; 32.7%). The other groups account for <1% of our sample [G1: 3,474 (0.1%), G2: 16,627 (0.6%), and G3: 6,866 (0.3%)]. The deaths related to SARI were more frequent in G4 (574,887; 34.7%); however, the deaths not related to SARI were more frequent among the patients categorized into the G3 (1,339; 21.3%) and G5 (25,829; 4.1%). In the multivariate analysis, the main predictors to classify the patients in the G5 when compared with G4 or G1-G4 were female sex, younger age, Black race, low educational level, rural place of residence, and the use of antiviral to treat the clinical signs. Furthermore, several features predict the risk of death by SARI, such as older age, race (Black, Indigenous, and multiracial background), low educational level, residence in a flu outbreak region, need for intensive care unit, and need for mechanical ventilatory support.

Conclusions

The possible COVID-19 underreporting (G5) might be associated with an enhanced mortality rate, more evident in distinct social groups. In addition, the patients' features are unequal between the patients' groups and can be used to determine the risk of possible COVID-19 underreporting in our population. Patients with a higher risk of death had a different epidemiological profile when compared with patients who recovered from SARI, like older age, Black, Indigenous, and multiracial background races, low educational level, residence in a flu outbreak region, need for intensive care unit and need for mechanical ventilatory support.

Human adenovirus meningoencephalitis: a 3-years' overview

Human adenovirus (HAdV) has been recognized as a significant viral pathogen implicated in neurological diseases, particularly in immunocompromised patients. However, its involvement in meningoencephalitis remains unclear. The aim of this study was to investigate HAdV and other viral co-infections in the cerebrospinal fluid (CSF) of patients suspected of having either meningoencephalitis or encephalitis. A total of 373 CSF samples from patients under clinical suspicion of neurological viral infection were included in this study. HAdV was investigated by conventional or multiplex real-time PCR, for different time periods. The frequency of HAdV central nervous system (CNS) infection was 1.08%, predominating in female patients with a predisposing condition, and presented with HAdV encephalitis. HAdV CNS infection was found to occur during the months of autumn and winter. The frequency of HAdV detected in CSF positive samples increased after the change in the diagnostic method from conventional to multiplex real-time PCR. There were no specific NMRI or EEG characteristics and two CSF samples with HAdV encephalitis had normal CSF WBC count. There were two cases of co-infection with HIV; no other co-infections with enterovirus or herpes family viruses were detected. All patients had good outcome. Although HAdV is rarely observable in CNS infectious syndromes, it must be investigated particularly in immunocompromised patients.

Global Influenza Hospital-based Surveillance Network (GIHSN): results of surveillance of influenza and other respiratory viruses in hospitalised patients in Brazil, 2015

BACKGROUND

Influenza-like illness occurs annually worldwide, with peak timing and severity varying seasonally, resulting in significant annual mortality.

OBJECTIVES

There were three objectives: (1) to describe the epidemiological and clinical features of hospitalised patients with severe acute respiratory infection caused by influenza and other respiratory viruses (ORVs); (2) to report the influenza seasonality in the region and (3) to correlate findings of influenza circulation and immunisation time in Brazil.

PATIENTS/METHODS

This study took place in three Brazilian hospitals located in cities with different climatic conditions (Curitiba (south), Rio de Janeiro (south-east) and Fortaleza (north-east)). Patients presenting with an acute process with indication for admission consisting of a predefined set of conditions potentially associated with recent influenza infection were enrolled.

RESULTS

We screened 1666 patients, with 595 meeting the inclusion criteria. Influenza viruses and ORVs were detected in 6.5% and 59% of patients, respectively. Influenza-positive cases fell into the severe spectrum as compared with those with ORVs (30% vs 11%), but without any difference in mortality rates. Epidemiological results revealed variations in the peak time of influenza infections between north-east (Fortaleza) and south (Curitiba) Brazil, basically following the rain period of each region. In north-east Brazil, viral circulation was prevalent in the first 4 months of the year, indicating that the vaccination campaign occurred in a postseasonal period, possibly explaining the low effectiveness.

CONCLUSIONS

The active-surveillance model is a valuable tool for investigating respiratory virus impact on hospitalised patients, with influenza-infection monitoring enabling implementation of adequate preventive 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.

Clinical and epidemiological features of respiratory virus infections in preschool children over two consecutive influenza seasons in southern Brazil

This study reports the results of a systematic screening for respiratory viruses in pediatric outpatients from an emergency department (ED) in southern Brazil during two consecutive influenza seasons. Children eligible for enrollment in this study were aged 24–59 months and presented with acute respiratory symptoms and fever. Naso‐ and oropharyngeal swabs were collected and multiplex reverse transcription PCR (RT‐PCR) was performed to identify the respiratory viruses involved. In total, 492 children were included in this study: 248 in 2010 and 244 in 2011. In 2010, 136 samples (55%) were found to be positive for at least one virus and the most frequently detected viruses were human rhinovirus (HRV) (18%), adenovirus (AdV) (13%), and human coronavirus (CoV) (5%). In 2011, 158 samples (65%) were found to be positive for at least one virus, and the most frequently detected were HRV (29%), AdV (12%), and enterovirus (9%). Further, the presence of asthma (OR, 3.17; 95% CI, 1.86–5.46) was independently associated with HRV infection, whereas fever was associated with AdV (OR, 3.86; 95% CI, 1.31–16.52) and influenza infections (OR, 3.74; 95% CI, 1.26–16.06). Ten patients (2%) were diagnosed with pneumonia, and six of these tested positive for viral infection (4 HRV, 1 RSV, and 1 AdV). Thus, this study identified the most common respiratory viruses found in preschool children in the study region and demonstrated their high frequency, highlighting the need for improved data collection, and case management in order to stimulate preventive measures against these infections. J. Med. Virol. 88:1325–1333, 2016. © 2016 Wiley Periodicals, Inc.

Identification of a novel human rhinovirus C type by antibody capture VIDISCA-454

Causative agents for more than 30 percent of respiratory infections remain unidentified, suggesting that unknown respiratory pathogens might be involved. In this study, antibody capture VIDISCA-454 (virus discovery cDNA-AFLP combined with Roche 454 high-throughput sequencing) resulted in the discovery of a novel type of rhinovirus C (RV-C). The virus has an RNA genome of at least 7054 nt and carries the characteristics of rhinovirus C species. The gene encoding viral protein 1, which is used for typing, has only 81% nucleotide sequence identity with the closest known RV-C type, and, therefore, the virus represents the first member of a novel type, named RV-C54.

Systematic review and meta-analysis of respiratory syncytial virus infection epidemiology in Latin America

Respiratory syncytial virus (RSV) is a frequent cause of acute respiratory infection and the most common cause of bronchiolitis in infants. The aim of this systematic review and meta-analysis was to obtain a comprehensive epidemiological picture of the data available on disease burden, surveillance, and use of resources in Latin America. Pooled estimates are useful for cross-country comparisons. Data from published studies reporting patients with probable or confirmed RSV infection in medical databases and gray literature were included from 74 studies selected from the 291 initially identified. When considering all countries, the largest pooled percentage RSV in low respiratory tract infection patients was found in the group between 0 and 11 months old, 41.5% (95% CI 32.0–51.4). In all countries, percentages were increasingly lower as older children were included in the analyses. The pooled percentage of RSV in LRTIs in the elderly people was 12.6 (95% CI 4.2–24.6). The percentage of RSV infection in hospitalized newborns was 40.9% (95% CI 28.28–54.34). The pooled case fatality ratio for RSV infection was 1.74% (95% CI 1.2–2.4) in the first 2 years of life. The average length of stay excluding intensive care unit admissions among children with risk factors for severe disease was 12.8 (95% CI 8.9–16.7) days, whereas it averaged 7.3 (95% CI 6.1/8.5) days in otherwise healthy children.We could conclude that infants in their first year of age were the most vulnerable population. To our knowledge, this is the first systematic review on RSV disease burden and use of health resources in Latin America.

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)

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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.

Seasonality and prevalence of respiratory pathogens detected by multiplex PCR at a tertiary care medical center

Respiratory tract infections (RTIs) are a leading cause of mortality and morbidity. Seasonality has been reported for many viruses, including influenza virus, respiratory syncytial virus (RSV), and the recently described human metapneumovirus (hMPV). We hypothesize that the availability of rapid, multiplex PCR diagnostics will provide better clinical care and new insights into the etiology and clinical spectrum of RTIs. We conducted a retrospective analysis of the incidence of respiratory pathogens at a 500-bed adult and 154-bed pediatric hospital tertiary care center. A total of 939 specimens from patients with an age range of 5 days to 91 years (median, 2 years) were tested by a multiplex respiratory pathogen PCR from November 14, 2011 to November 13, 2012. Sixty-five percent of specimens were positive for at least one pathogen. As the age of the patient increased, the positivity rate for the PCR decreased proportionately. Rhinoviruses/enteroviruses (Rhino/Entero) were the most prevalent (34.3 %) followed by RSV (19.2 %) and hMPV (6.2 %). Twelve percent of the positive samples were positive for multiple analytes, with Rhino/Entero and RSV being the most common combination. The peak months were September and May for Rhino/Entero infections, January for RSV and February for coronavirus. hMPV peaked 2 months after RSV, as has been observed recently in other studies. Multiplex PCR provides rapid diagnostic information that can be used to make knowledgeable clinical decisions and potentially reduce the use of antibiotics. Active respiratory PCR surveillance could also predict seasonal respiratory epidemics to allow for adequate planning of additional infection control measures.

Respiratory syncytial virus epidemic periods in an equatorial city of Brazil

Background

Characterization of the human respiratory syncytial virus (HRSV) season at the local level has important implications for appropriate decisions on the time period for administration of specific prophylaxis.

Objectives

(1) To describe five consecutive epidemic periods of HRSV in an equatorial city of Brazil and (2) to show preliminary data on genomic diversity of circulating HRSV.

Patients/Methods

Nasopharyngeal aspirates of 2885 children attending the emergency room and wards of a public hospital were collected and screened by indirect immunofluorescence for HRSV infections during five consecutive years (from January 2004 to December 2008). In addition, the genetic and antigenic variability of the HRSV strains isolated was evaluated by partial nucleotide sequencing of the protein G gene.

Results

HRSV was detected in 15·8% of the analyzed samples. HRSV seasons occurred in a restricted period of each year. The onset of each HRSV season was variable (February to May), but the end always occurred in July. From the 456 HRSV infections found, 86 cases with bronchiolitis were genotyped. Both HRSV subgroups (A and B) cocirculated during the five epidemic periods. The 58 HRSV‐A strains grouped into two clades, GA2 and GA5. In respect of the HRSV‐B strains, the 28 samples grouped into two clades: GB3 and BA.

Conclusions

HRSV accounts for a substantial proportion of ARI in the study population. As in temperate countries, HRSV infections in this equatorial area of Brazil also cause seasonal yearly epidemics, and this has implications for prophylaxis strategies. The city of Fortaleza follows the same worldwide trend of circulation of genotypes of HRSV.

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.

Seasonality of viral respiratory infections in southeast of Brazil: the influence of temperature and air humidity

Viruses are the major cause of lower respiratory tract infections in childhood and the main viruses involved are Human Respiratory Syncytial Virus (HRSV), Human Metapneumovirus (HMPV), Influenzavirus A and B (FLUA and FLUB), Human Parainfluenza Virus 1, 2 and 3 (HPIV1, 2 and 3) and Human Rhinovirus (HRV). The purposes of this study were to detect respiratory viruses in hospitalized children younger than six years and identify the influence of temperature and relative air humidity on the detected viruses. Samples of nasopharyngeal washes were collected from hospitalized children between May/2004 and September/2005. Methods of viral detection were RT-PCR, PCR and HRV amplicons were confirmed by hybridization. Results showed 54% (148/272) of viral positivity. HRSV was detected in 29% (79/272) of the samples; HRV in 23.1% (63/272); HPIV3 in 5.1% (14/272); HMPV in 3.3% (9/272); HPIV1 in 2.9% (8/272); FLUB in 1.4% (4/272), FLUA in 1.1% (3/272), and HPIV2 in 0.3% (1/272). The highest detection rates occurred mainly in the spring 2004 and in the autumn 2005. It was observed that viral respiratory infections tend to increase as the relative air humidity decreases, showing significant association with monthly averages of minimal temperature and minimal relative air humidity. In conclusion, viral respiratory infections vary according to temperature and relative air humidity and viral respiratory infections present major incidences it coldest and driest periods.

Use of sensitive, broad-spectrum molecular assays and human airway epithelium cultures for detection of respiratory pathogens

Rapid and accurate detection and identification of viruses causing respiratory tract infections is important for patient care and disease control. Despite the fact that several assays are available, identification of an etiological agent is not possible in ~30% of patients suffering from respiratory tract diseases. Therefore, the aim of the current study was to develop a diagnostic set for the detection of respiratory viruses with sensitivity as low as 1-10 copies per reaction. Evaluation of the assay using a training clinical sample set showed that viral nucleic acids were identified in ~76% of cases. To improve assay performance and facilitate the identification of novel species or emerging strains, cultures of fully differentiated human airway epithelium were used to pre-amplify infectious viruses. This additional step resulted in the detection of pathogens in all samples tested. Based on these results it can be hypothesized that the lack of an etiological agent in some clinical samples, both reported previously and observed in the present study, may result not only from the presence of unknown viral species, but also from imperfections in the detection methods used.

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.

Impact of human metapneumovirus infection on in and outpatients for the years 2006-2008 in Southern Brazil

The human metapneumovirus (hMPV), member of the Paramyxoviridae family, has been reported as an important agent involved with acute respiratory infections (ARIs). The aim of this study is to identify hMPV as the etiological agent of ARIs on in and outpatients in the city of Curitiba, Southern Brazil, and describe clinical data of hMPV subtyping. A retrospective study was performed in 1,572 respiratory samples over a period of three years. hMPV was detected by reverse transcription-polymerase chain reaction and subtyping was performed by nucleotide sequencing. hMPV was present in 61 (3.9%) samples and subtypes A1, A2a, B1 and B2 were detected. The incidence of hMPV was higher in outpatients (5.9%), whose mean age was 19.7 years (range 6 months-75 years old), than in inpatients (3%), whose mean age was 7.6 months (range 1 month-26 years old). The outpatients had upper respiratory tract infections with flu-like symptoms and all hospitalized children had lower respiratory tract infections. A pediatric patient died from complications associated with hMPV A2a infection. hMPV has been reported as a respiratory pathogen in all age groups. No correlation was observed between viral subtype and disease severity in the samples of this study.

Laboratory diagnosis, epidemiology, and clinical outcomes of pandemic influenza A and community respiratory viral infections in southern Brazil

Community respiratory viruses (CRVs) are commonly associated with seasonal infections. They have been associated with higher morbidity and mortality among children, elderly individuals, and immunosuppressed patients. In April 2009, the circulation of a new influenza A virus (FLUA H1N1v) was responsible for the first influenza pandemic of this century. We report the clinical and epidemiological profiles of inpatients infected with CRVs or with FLUA H1N1v at a tertiary care hospital in southern Brazil. In addition, we used these profiles to evaluate survivor and nonsurvivor patients infected with FLUA H1N1v. Multiplex reverse transcription-PCR (RT-PCR) and real time RT-PCR were used to detect viruses in inpatients with respiratory infections. Record data from all patients were reviewed. A total of 171 patients were examined over a period of 16 weeks. Of these, 39% were positive for FLUA H1N1v, 36% were positive for CRVs, and 25% were negative. For the FLUA H1N1v- and CRV-infected patients, epidemiological data regarding median age (30 and 1.5 years), myalgia (44% and 13%), need for mechanical ventilation (44% and 9%), and mortality (35% and 9%) were statistically different. In a multivariate analysis comparing survivor and nonsurvivor patients infected with influenza A virus H1N1, median age and creatine phosphokinase levels were significantly associated with a severe outcome. Seasonal respiratory infections are a continuing concern. Our results highlight the importance of studies on the prevalence and severity of these infections and that investments in programs of clinical and laboratory monitoring are essential to detect the appearance of new infective agents.

Human metapneumovirus infection in hematopoietic stem cell transplant recipients

Human metapneumovirus (hMPV) was described in 2001 and has been associated with both upper and lower respiratory tract infection (URTI and LRTI, respectively), especially in children, the elderly, and in immunocompromised patients. The objective of this study was to identify hMPV as the etiological agent of acute respiratory infection in hematopoietic stem cell transplant (HSCT) patients and to determine the clinical features of hMPV infection in these patients.

METHODS

The study was performed retrospectively in 769 respiratory samples obtained from immunocompromised patients submitted to HSCT over a period of 6 years. RNA was extracted by the guanidinium thiocyanate method, and reverse transcription polymerase chain reaction assay was performed to amplify a 928pb fragment of the hMPV N gene.

RESULTS

hMPV was present in 19 (2.5%) samples. The mean age of infected patients was 18.3+/-10.8 (range, 3-41). Sixty-six percent of hMPV infections occurred during autumn, winter, and spring months. Three episodes showed co-infection with more than 1 virus. Two patients (11.1%) were infected a few days into the conditioning period and 9 (50%) in the first 3 months after the transplant. The majority of patients (72.2%) presented URTI alone with flu-like symptoms (cough, fever, headache, wheezing), while 5 patients (27.8%) had LRTI (pneumonia). No patient died from complications associated with the hMPV infection.

CONCLUSIONS

hMPV has been reported as a respiratory pathogen in HSCT patients. We suggest that hMPV infection should be routinely investigated in this population, mainly in children, to prevent nosocomial transmission during transplant proceedings and to avoid the risk of progressing to complications due to LRTI.

Respiratory viruses in pediatric necropsies: an immunohistochemical study

Infections of the respiratory system are responsible for the majority of hospitalizations and deaths in pediatric patients in developing countries. We selected 177 necropsies of pediatric patients who died as a result of serious respiratory infections. The histopathological findings and epidemiological data were reviewed, and lung tissue samples were separated for immunohistochemistry testing. Conventional immunohistochemistry techniques were used to detect viral antigens in formalin-fixed, paraffin-embedded (FF-PE) lung tissue samples using a pool of monoclonal antibodies against respiratory viruses (respiratory syncytial virus, influenza A and B, adenovirus, and parainfluenza 1, 2, and 3 viruses) as primary antibodies. The histopathological findings were classified into bronchopneumonia (BCP) and interstitial pneumonitis (IP) patterns. The immunohistochemistry results were compared with histopathological patterns and epidemiological data. Positive results for viruses were found in 34% and 62.5% of the BCP and IP cases, respectively. Males and infants below 1 year of age were more frequent in the group that had positive results for viruses. Acute enteritis was the main cause of hospitalization and sepsis the most frequent cause of death in this group. A clear seasonal distribution was observed, with the majority of cases occurring in the 2nd and 3rd trimesters (autumn and winter) of each year in the period studied. Immunohistochemistry is an affordable and easy-to-perform method for viral-antigen detection in FF-PE tissue samples. Although BCP is a classic histopathological pattern found in bacterial infections, it is possible that children with serious respiratory infections had concomitant viral and bacterial infections, regardless of their previous immunologic state.

Novel respiratory virus infections in children, Brazil

Recently discovered respiratory viruses were detected in 19 (9.2%) of 205 nasal swab specimens from children in Brazil with respiratory illnesses. Five each were positive for human metapneumovirus (HMPV) alone and human bocavirus (HBoV) alone, 3 for human coronaviruses (HCoV-HKU1 or -NL63) alone, and 6 for more than 1 recently discovered virus.

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.

Respiratory viruses in children younger than five years old with acute respiratory disease from 2001 to 2004 in Uberlândia, MG, Brazil

The main viruses involved in acute respiratory diseases among children are: respiratory syncytial virus (RSV), influenzavirus (FLU), parainfluenzavirus (PIV), adenovirus (AdV), human rhinovirus (HRV), and the human metapneumovirus (hMPV). The purpose of the present study was to identify respiratory viruses that affected children younger than five years old in Uberlândia, Midwestern Brazil. Nasopharyngeal aspirates from 379 children attended at Hospital de Clínicas (HC/UFU), from 2001 to 2004, with acute respiratory disease, were collected and tested by immunofluorescence assay (IFA) to detect RSV, FLU A and B, PIV 1, 2, and 3 and AdV, and RT-PCR to detect HRV. RSV was detected in 26.4% (100/379) of samples, FLU A and B in 9.5% (36/379), PIV 1, 2 and 3 in 6.3% (24/379) and AdV in 3.7% (14/379). HRV were detected in 29.6% (112/379) of the negative and indeterminate samples tested by IFI. RSV, particularly among children less than six months of life, and HRV cases showed highest incidence. Negative samples by both IFA and RT-PCR might reflect the presence of other pathogens, such as hMPV, coronavirus, and bacteria. Laboratorial diagnosis constituted an essential instrument to determine the incidence of the most common viruses in respiratory infections among children in this region.