Fatal influenza B virus pneumonia in a preterm neonate: case report and review of the literature

Effect of risk factors on the prevalence of influenza infections among children of slums of Dhaka city

Background

Influenza viruses may cause severe acute respiratory illness among human population. People of densely populated areas, e.g., slum, are mostly affected by influenza viruses. Although potential vaccines to influenza viruses have been developed, infection rate is still high, therefore, increase the morbidity and mortality rate in slum areas. To treat these infections, slum dwellers including children and mothers do not get proper medication as well as vaccination. Hence, prevention remains to be the only mean to tackle such infections. Herein, we determined the prevalence of influenza infections among nutritionally deprived children and mothers of slum areas in Dhaka city and demonstrated the association with different risk factors like age, gender and socio-economic status.

Results

Nasopharyngeal swab samples and a short demography of all the participants suffering from influenza-like illness (ILI) were collected. The samples were subjected to RNA extraction and then real-time RT-PCR to detect influenza viruses. Among the ILI patients, about 87.9 % did not have knowledge about influenza infections and 80.5 % did not cover their noses during coughing as well as sneezing. Children were significantly infected by both influenza A and influenza B viruses, suggesting their vulnerability to these infections. Additionally, among the children with ILI, influenza infections were significantly associated with age below or equal to three years, very poor family incomes, practicing unhygienic habits and nutritional deficiency.

Conclusions

This study suggests that proper vaccination, improved sanitary conditions and nutritional diet may help reduce the risk of influenza infections in slum areas.

Competitive fitness of influenza B viruses with neuraminidase inhibitor-resistant substitutions in a coinfection model of the human airway epithelium

Influenza A and B viruses are human pathogens that are regarded to cause almost equally significant disease burdens. Neuraminidase (NA) inhibitors (NAIs) are the only class of drugs available to treat influenza A and B virus infections, so the development of NAI-resistant viruses with superior fitness is a public health concern. The fitness of NAI-resistant influenza B viruses has not been widely studied. Here we examined the replicative capacity and relative fitness in normal human bronchial epithelial (NHBE) cells of recombinant influenza B/Yamanashi/166/1998 viruses containing a single amino acid substitution in NA generated by reverse genetics (rg) that is associated with NAI resistance. The replication in NHBE cells of viruses with reduced inhibition by oseltamivir (recombinant virus with the E119A mutation generated by reverse genetics [rg-E119A], rg-D198E, rg-I222T, rg-H274Y, rg-N294S, and rg-R371K, N2 numbering) or zanamivir (rg-E119A and rg-R371K) failed to be inhibited by the presence of the respective NAI. In a fluorescence-based assay, detection of rg-E119A was easily masked by the presence of NAI-susceptible virus. We coinfected NHBE cells with NAI-susceptible and -resistant viruses and used next-generation deep sequencing to reveal the order of relative fitness compared to that of recombinant wild-type (WT) virus generated by reverse genetics (rg-WT): rg-H274Y > rg-WT > rg-I222T > rg-N294S > rg-D198E > rg-E119A ≫ rg-R371K. Based on the lack of attenuated replication of rg-E119A in NHBE cells in the presence of oseltamivir or zanamivir and the fitness advantage of rg-H274Y over rg-WT, we emphasize the importance of these substitutions in the NA glycoprotein. Human infections with influenza B viruses carrying the E119A or H274Y substitution could limit the therapeutic options for those infected; the emergence of such viruses should be closely monitored.

IMPORTANCE

Influenza B viruses are important human respiratory pathogens contributing to a significant portion of seasonal influenza virus infections worldwide. The development of resistance to a single class of available antivirals, the neuraminidase (NA) inhibitors (NAIs), is a public health concern. Amino acid substitutions in the NA glycoprotein of influenza B virus not only can confer antiviral resistance but also can alter viral fitness. Here we used normal human bronchial epithelial (NHBE) cells, a model of the human upper respiratory tract, to examine the replicative capacities and fitness of NAI-resistant influenza B viruses. We show that virus with an E119A NA substitution can replicate efficiently in NHBE cells in the presence of oseltamivir or zanamivir and that virus with the H274Y NA substitution has a relative fitness greater than that of the wild-type NAI-susceptible virus. This study is the first to use NHBE cells to determine the fitness of NAI-resistant influenza B viruses.

Influenza B virus-associated pneumonia in pediatric patients: clinical features, laboratory data, and chest X-ray findings

BACKGROUND

The clinical significance of influenza B is frequently overlooked, and reports on influenza B pneumonia in children are limited. Therefore, the clinical features of associated complications have rarely been reported. The aim of this study is to evaluate the clinical characteristics in pediatric patients with influenza B virus-associated pneumonia.

METHODS

From January 2009 to February 2012, 389 consecutive patients under 18 years old with influenza B virus infection were enrolled into the study. Thirty-four patients were defined as the pneumonia group by clinical symptoms and chest X-ray (CXR) findings, and 90 patients who had laboratory data and normal CXR findings were recruited to form the nonpneumonia group.

RESULTS

The age of the patients in the pneumonia group was significantly younger (median of 5.3 vs. 6.6 years). The white blood cell count (median of 7.5 vs. 5.7 × 10(9) cells/L) and C-reactive protein level (median of 21.1 vs. 5.7 mg/L) were higher, but the hemoglobin level was lower (median of 12.6 vs. 13.2 g/dL) in the pneumonia group. The CXR findings revealed that 29.4% of patients had alveolar consolidation, 32.4% had interstitial infiltration, and 38.2% had ground glass opacity. Two of four patients with pleural effusion had a positive bacteria culture, and both of them died.

CONCLUSION

Pneumonia should be considered in pediatric patients with influenza B virus infection presenting with younger age, higher white blood cell count, lower hemoglobin, and higher C-reactive protein level. The CXR findings were varied. Patients with pleural effusion and positive bacterial culture may have more severity of clinical outcome.

Prenatal influenza exposure and cardiovascular events in adulthood

Objectives

This study examined the association between prenatal exposure to pandemic influenza and cardiovascular events in adulthood.

Design

Using Danish surveillance data to identify months when influenza activity was highest during three previous pandemics (1918, 1957, and 1968), persons were defined as exposed/unexposed based on whether they were in utero during peak months of one of the pandemics. Episodes of acute myocardial infarction (MI) and stroke were identified in the Danish National Registry of Patients covering all Danish hospitals since 1977.

Setting/Sample

Information from Danish national registries on all persons with a Civil Personal Registry number and birthdates in 1915 through 1922, 1954 through 1960, and 1966 through 1972 was collected.

Main outcome measures

Crude incidence rate ratios (IRRs) were calculated per pandemic. Generalized linear models were fit to estimate IRRs adjusted for sex.

Results

For acute MI, sex-adjusted IRRs for persons in utero during peaks of the 1918, 1957, and 1968 pandemics, compared with those born afterward, were 1·02 (95% confidence interval (CI): 0·99, 1·05), 0·96 (95% CI: 0·87, 1·05), and 1·18 (95% CI: 0·96, 1·45), respectively. For stroke, the corresponding IRRs were 0·99 (95% CI: 0·97, 1·02), 0·99 (95% CI: 0·92, 1·05), and 0·85 (95% CI: 0·77, 0·94), respectively.

Conclusions

There was generally no evidence of an association between prenatal influenza exposure and acute MI or stroke in adulthood. However, survivor bias and left truncation of outcomes for the 1918 pandemic are possible, and the current young ages of persons included in the analyses for the 1957 and 1968 pandemics may warrant later re-evaluation.

Neuraminidase inhibitors for influenza B virus infection: efficacy and resistance

Many aspects of the biology and epidemiology of influenza B viruses are far less studied than for influenza A viruses, and one of these aspects is efficacy and resistance to the clinically available antiviral drugs, the neuraminidase (NA) inhibitors (NAIs). Acute respiratory infections are one of the leading causes of death in children and adults, and influenza is among the few respiratory infections that can be prevented and treated by vaccination and antiviral treatment. Recent data has suggested that influenza B virus infections are of specific concern to pediatric patients because of the increased risk of severe disease. Treatment of influenza B is a challenging task for the following reasons: This review presents current knowledge of the efficacy of NAIs for influenza B virus and antiviral resistance in clinical, surveillance, and experimental studies.

Prevention of novel influenza infection in newborns in hospital settings: considerations and strategies during the 2009 H1N1 pandemic

During the 2009 influenza A (H1N1) pandemic, many pregnant women experienced severe illness and some gave birth while ill with suspected or confirmed pandemic (H1N1) 2009 influenza. Because of concerns about possible transmission of this novel virus to immunologically naïve newborns, and the absence of definitive studies regarding this risk, the Centers for Disease Control and Prevention (CDC) reviewed relevant literature to understand the potential burden of disease and routes of transmission affecting newborns. This report describes the issues considered during the 2009 H1N1 pandemic as CDC developed guidance to protect newborns in hospital settings. Also presented is a framework of protection efforts to prevent novel influenza infection in fetuses/newborns before birth and in hospital settings. Although developed specifically for the pandemic, the framework may be useful during future novel influenza outbreaks.

Prevalence of influenza A and B antibodies in pregnant women and their offspring

BACKGROUND

Influenza is associated with substantial morbidity and mortality in pregnant women and neonates, but few countries offer annual influenza vaccination with the inactivated vaccine to all women who are, or intend to become, pregnant.

OBJECTIVES

To provide seroepidemiological information on influenza A and B antibodies in pregnant women and their offspring in Germany.

STUDY DESIGN

Anti-influenza antibodies were determined using commercially available enzyme-linked immunosorbent assays (ELISA) on serum obtained from 209 women and their newborns at delivery.

RESULTS

The prevalence of antibodies against influenza A virus was 93.8% [89.6-96.6%] in the mothers and 96.7% [93.2-98.6%] in the newborns. The prevalence of antibodies against influenza B virus was 42.1% [35.3-49.1%] in the mothers and 78.5% [72.3-83.8%] in their newborns, which was a significant difference. The antibody concentrations against both influenza A and influenza B viruses were significantly lower in mother than in their newborns.

CONCLUSIONS

Because of active placental transport of IgG antibodies, neonates have higher prevalence and/or concentrations of influenza A and B virus-specific antibodies induced by natural infections than their mothers. Considering these serological findings, especially the lower prevalence of maternal antibody against influenza B virus, annual influenza vaccination may improve the protection of pregnant women and their offspring against influenza.

Sepsis in the neonate

In the neonatal intensive care unit, critical care nurses who are not advanced practice nurses cannot make the medical diagnosis of infection/sepsis in the neonate. Even so, the critical care nurse has a critical role in dealing with sepsis infection. The nurse must (1) have a high index of suspicion about the risk of infection, (2) be able to recognize septic/infected newborns, (3) report related concerns to the physician or advanced practice nurse, and (4) advocate on behalf of the infant to ensure a timely diagnostic workup and empiric antibiotics. This article is a guide for understanding issues related to sepsis in the neonatal intensive care unit.