Broad spectrum respiratory pathogen analysis of throat swabs from military recruits reveals interference between rhinoviruses and adenoviruses

Decreased risk of non-influenza respiratory infection after influenza B virus infection in children

Previous studies suggest that influenza virus infection may provide temporary non-specific immunity and hence lower the risk of non-influenza respiratory virus infection. In a randomized controlled trial of influenza vaccination, 1 330 children were followed-up in 2009-2011. Respiratory swabs were collected when they reported acute respiratory illness and tested against influenza and other respiratory viruses. We used Poisson regression to compare the incidence of non-influenza respiratory virus infection before and after influenza virus infection. Based on 52 children with influenza B virus infection, the incidence rate ratio (IRR) of non-influenza respiratory virus infection after influenza virus infection was 0.47 (95% confidence interval: 0.27-0.82) compared with before infection. Simulation suggested that this IRR was 0.87 if the temporary protection did not exist. We identified a decreased risk of non-influenza respiratory virus infection after influenza B virus infection in children. Further investigation is needed to determine if this decreased risk could be attributed to temporary non-specific immunity acquired from influenza virus infection.

Roles for Pathogen Interference in Influenza Vaccination, with Implications to Vaccine Effectiveness (VE) and Attribution of Influenza Deaths

Pathogen interference is the ability of one pathogen to alter the course and clinical outcomes of infection by another. With up to 3000 species of human pathogens the potential combinations are vast. These combinations operate within further immune complexity induced by infection with multiple persistent pathogens, and by the role which the human microbiome plays in maintaining health, immune function, and resistance to infection. All the above are further complicated by malnutrition in children and the elderly. Influenza vaccination offers a measure of protection for elderly individuals subsequently infected with influenza. However, all vaccines induce both specific and non-specific effects. The specific effects involve stimulation of humoral and cellular immunity, while the nonspecific effects are far more nuanced including changes in gene expression patterns and production of small RNAs which contribute to pathogen interference. Little is known about the outcomes of vaccinated elderly not subsequently infected with influenza but infected with multiple other non-influenza winter pathogens. In this review we propose that in certain years the specific antigen mix in the seasonal influenza vaccine inadvertently increases the risk of infection from other non-influenza pathogens. The possibility that vaccination could upset the pathogen balance, and that the timing of vaccination relative to the pathogen balance was critical to success, was proposed in 2010 but was seemingly ignored. Persons vaccinated early in the winter are more likely to experience higher pathogen interference. Implications to the estimation of vaccine effectiveness and influenza deaths are discussed.

A Historical Review of Military Medical Strategies for Fighting Infectious Diseases: From Battlefields to Global Health

The environmental conditions generated by war and characterized by poverty, undernutrition, stress, difficult access to safe water and food as well as lack of environmental and personal hygiene favor the spread of many infectious diseases. Epidemic typhus, plague, malaria, cholera, typhoid fever, hepatitis, tetanus, and smallpox have nearly constantly accompanied wars, frequently deeply conditioning the outcome of battles/wars more than weapons and military strategy. At the end of the nineteenth century, with the birth of bacteriology, military medical researchers in Germany, the United Kingdom, and France were active in discovering the etiological agents of some diseases and in developing preventive vaccines. Emil von Behring, Ronald Ross and Charles Laveran, who were or served as military physicians, won the first, the second, and the seventh Nobel Prize for Physiology or Medicine for discovering passive anti-diphtheria/tetanus immunotherapy and for identifying mosquito Anopheline as a malaria vector and plasmodium as its etiological agent, respectively. Meanwhile, Major Walter Reed in the United States of America discovered the mosquito vector of yellow fever, thus paving the way for its prevention by vector control. In this work, the military relevance of some vaccine-preventable and non-vaccine-preventable infectious diseases, as well as of biological weapons, and the military contributions to their control will be described. Currently, the civil-military medical collaboration is getting closer and becoming interdependent, from research and development for the prevention of infectious diseases to disasters and emergencies management, as recently demonstrated in Ebola and Zika outbreaks and the COVID-19 pandemic, even with the high biocontainment aeromedical evacuation, in a sort of global health diplomacy.

Virus-virus interactions of febrile respiratory syndrome among patients in China based on surveillance data from February 2011 to December 2020

BACKGROUND

The burden of acute respiratory infections is still considerable, and virus-virus interactions may affect their epidemics, but previous evidence is inconclusive.

OBJECTIVE

To quantitatively investigate the interactions among respiratory viruses at both the population and individual levels.

METHODS

Cases tested for influenza virus (IV), respiratory syncytial virus (RSV), human parainfluenza virus (PIV), human Adenovirus (AdV), human coronavirus (CoV), human bocavirus (BoV) and rhinoviruses (RV) were collected from the pathogen surveillance for febrile respiratory syndrome (FRS) in China from February 2011 to December 2020. We used spearman's rank correlation coefficients and binary logistic regression models to analyze the interactions between any two of the viruses at the population and individual levels, respectively.

RESULTS

Among 120,237 cases, 4.5% were co-infected with two or more viruses. Correlation coefficients showed 7 virus pairs were positively correlated, namely: IV and RSV, PIV and AdV, PIV and CoV, PIV and BoV, PIV and RV, AdV and BoV, CoV and RV. Regression models showed except for the negative interaction between IV and RV (OR=0.70, 95%CI: 0.61-0.81), all other virus pairs had positive interactions.

CONCLUSION

Most of the respiratory viruses interact positively, while IV and RV interact negatively. This article is protected by copyright. All rights reserved.

Acute flaccid paralysis and neurogenic respiratory failure associated with enterovirus D68 infection in children: Report of two cases

BACKGROUND

Acute flaccid paralysis (AFP) and neurogenic respiratory failure rarely occur in children. At the end of 2018, some children with such symptoms were admitted to our hospital. In this study, we aimed to assess two children with AFP and neurogenic respiratory failure associated with enterovirus D68 (EV-D68).

CASE SUMMARY

Two children admitted to our hospital presented with symptoms and imaging results different from those of acute disseminated encephalomyelitis and hand, foot, and mouth disease. Their main symptoms were AFP and neurogenic respiratory failure. Magnetic resonance imaging showed severe inflammatory injury mainly to the anterior horn cells of the spinal cord. Blood and cerebrospinal fluid samples were collected to assess for pathogens, including bacteria, tuberculosis, cryptococcus, herpes virus, and coxsackie virus, and the results were negative. At the beginning, the two cases were not assessed for EV-D68 in the nasopharyngeal, blood, and cerebrospinal fluid specimens. About 2 mo later, EV-D68 was detected in the stool sample of one of the cases. The symptom of AFP was caused by injury to the anterior horn cells at levels C5-L5 of the spinal cord, while neurogenic respiratory failure was at levels C3-C5.

CONCLUSION

We should pay attention to the detection and diagnosis of EV-D68 and make efforts to develop antivirus drugs and vaccines.

Evidence for Cross-Protection Against Subsequent Febrile Respiratory Illness Episodes From Prior Infections by Different Viruses Among Singapore Military Recruits 2009-2014

Background

Few studies have evaluated the relative cross-protection conferred by infection with different groups of viruses through studies of sequential infections in humans. We investigated the presence of short-lived relative cross-protection conferred by specific prior viral infections against subsequent febrile respiratory illness (FRI).

Methods

Men enlisted in basic military training between December 2009 and December 2014 were recruited, with the first FRI as the study entry point. ResPlex II assays and real-time polymerase chain reaction assays were used to detect viral pathogens in nasal wash samples, and survival analyses were performed to determine whether infection with particular viruses conferred short-lived relative cross-protection against FRI.

Results

Prior infection with adenovirus (hazard ratio [HR], 0.24; 95% confidence interval [CI], .14–.44) or influenza virus (HR, 0.52; 95% CI, .38–.73) conferred relative protection against subsequent FRI episode. Results were statistically significant even after adjustment for the interval between enlistment and FRI (P < .001). Adenovirus-positive participants with FRI episodes tended to be protected against subsequent infection with adenovirus, coronavirus, enterovirus/rhinovirus, and influenza virus (P = .062–.093), while men with influenza virus–positive FRI episodes tended be protected against subsequent infection with adenovirus (P = .044) and influenza virus (P = .081).

Conclusion

Prior adenovirus or influenza virus infection conferred cross-protection against subsequent FRI episodes relative to prior infection due to other circulating viruses.

Prospective virome analyses in young children at increased genetic risk for type 1 diabetes

Viruses are implicated in autoimmune destruction of pancreatic islet β cells, which results in insulin deficiency and type 1 diabetes (T1D)1-4. Certain enteroviruses can infect β cells in vitro5, have been detected in the pancreatic islets of patients with T1D6 and have shown an association with T1D in meta-analyses4. However, establishing consistency in findings across studies has proven difficult. Obstacles to convincingly linking RNA viruses to islet autoimmunity may be attributed to rapid viral mutation rates, the cyclical periodicity of viruses7 and the selection of variants with altered pathogenicity and ability to spread in populations. β cells strongly express cell-surface coxsackie and adenovirus receptor (CXADR) genes, which can facilitate enterovirus infection8. Studies of human pancreata and cultured islets have shown significant variation in enteroviral virulence to β cells between serotypes and within the same serotype9,10. In this large-scale study of known eukaryotic DNA and RNA viruses in stools from children, we evaluated fecally shed viruses in relation to islet autoimmunity and T1D. This study showed that prolonged enterovirus B rather than independent, short-duration enterovirus B infections may be involved in the development of islet autoimmunity, but not T1D, in some young children. Furthermore, we found that fewer early-life human mastadenovirus C infections, as well as CXADR rs6517774, independently correlated with islet autoimmunity.

Virus genotyping by massive parallel amplicon sequencing: adenovirus and enterovirus in the Norwegian MIDIA study

OBJECTIVES

Direct genotyping of adenovirus or enterovirus from clinical material using polymerase chain reaction (PCR) followed by Sanger sequencing is often difficult due to the presence of multiple virus types in a sample, or due to varying efficacy of PCR amplifying the capsid gene on the background of foreign nucleic acids. Here we present a simple protocol for virus genotyping using massive parallel amplicon sequencing.

METHODS

The protocol utilized a set of 16 tailed degenerate primers flanking the seventh hypervariable region of the adenovirus hexon gene and 9 tailed degenerate primers targeted to the proximal portion of the enterovirus VP1 gene. Subsequent addition of dual indices enabled simultaneous sequencing of 384 different samples on an Illumina MiSeq instrument. Downstream bioinformatic analysis was based on remapping to a set of references representative of the presently known repertoire of virus types.

RESULTS

After validation with known virus types, the sequencing method was applied on 301 adenovirus-positive samples and 350 enterovirus-positive samples from a longitudinally collected series of stools from 83 children aged 3 to 36 months. We detected 7 different adenovirus types and 27 different enterovirus types. There were 37 (6.2%) samples containing more than one genotype of the same viral genus. At least one dual infection was experienced by 23 of 83 (28%) of the children observed over the 3 years' observation period.

CONCLUSIONS

Amplicon sequencing with a multiplex set of degenerate primers seems to be a rapid and reliable technical solution for genotyping of large collections of samples where simultaneous infections with multiple strains can be expected.

Association between semi-quantitative microbial load and respiratory symptoms among Thai military recruits: a prospective cohort study

BACKGROUND

Multiplex real-time polymerase chain reaction assays have improved diagnostic sensitivity for a wide range of pathogens. However, co-detection of multiple agents and bacterial colonization make it difficult to distinguish between asymptomatic infection or illness aetiology. We assessed whether semi-quantitative microbial load data can differentiate between symptomatic and asymptomatic states for common respiratory pathogens.

METHODS

We obtained throat and nasal swab samples from military trainees at two Thai Army barracks. Specimens were collected at the start and end of 10-week training periods (non-acute samples), and from individuals who developed upper respiratory tract infection during training (acute samples). We analysed the samples using a commercial multiplex respiratory panel comprising 33 bacterial, viral and fungal targets. We used random effects tobit models to compare cycle threshold (Ct) value distributions from non-acute and acute samples.

RESULTS

We analysed 341 non-acute and 145 acute swab samples from 274 participants. Haemophilus influenzae type B was the most commonly detected microbe (77.4% of non-acute and 64.8% of acute samples). In acute samples, nine specific microbe pairs were detected more frequently than expected by chance. Regression models indicated significantly lower microbial load in non-acute relative to acute samples for H. influenzae non-type B, Streptococcus pneumoniae and rhinovirus, although it was not possible to identify a Ct-value threshold indicating causal etiology for any of these organisms.

CONCLUSIONS

Semi-quantitative measures of microbial concentration did not reliably differentiate between illness and asymptomatic colonization, suggesting that clinical symptoms may not always be directly related to microbial load for common respiratory infections.

Adenovirus type 4 respiratory infections with a concurrent outbreak of coxsackievirus A21 among United States Army Basic Trainees, a retrospective viral etiology study using next-generation sequencing

Human adenoviruses (HAdV), in particular types 4 and 7, frequently cause acute respiratory disease (ARD) during basic military training. HAdV4 and HAdV7 vaccines reduced the ARD risk in U.S. military. It is important to identify other respiratory pathogens and assess their potential impact on military readiness. In 2002, during a period when the HAdV vaccines were not available, throat swabs were taken from trainees (n = 184) with respiratory infections at Fort Jackson, South Carolina. Viral etiology was investigated initially with viral culture and neutralization assay and recently in this study by sequencing the viral isolates. Viral culture and neutralization assays identified 90 HAdV4 isolates and 27 additional cultures that showed viral cytopathic effects (CPE), including some with picornavirus-like CPE. Next-generation sequencing confirmed these results and determined viral genotypes, including 77 HAdV4, 4 HAdV3, 1 HAdV2, 17 coxsackievirus A21 (CAV21), and 1 enterovirus D68. Two samples were positive for both HAdV4 and CAV21. The identified genotypes are phylogenetically close to but distinct from those found during other years or in other military/non-military sites. HAdV4 is the predominant respiratory pathogen in unvaccinated military trainee. HAdV4 has temporal and demographic variability. CAV21 is a significant respiratory pathogen and needs to be evaluated for its current significance in military basic trainees.

Enterovirus D-68 Infection, Prophylaxis, and Vaccination in a Novel Permissive Animal Model, the Cotton Rat (Sigmodon hispidus)

In recent years, there has been a significant increase in detection of Enterovirus D-68 (EV-D68) among patients with severe respiratory infections worldwide. EV-D68 is now recognized as a re-emerging pathogen; however, due to lack of a permissive animal model for EV-D68, a comprehensive understanding of the pathogenesis and immune response against EV-D68 has been hampered. Recently, it was shown that EV-D68 has a strong affinity for α2,6-linked sialic acids (SAs) and we have shown previously that α2,6-linked SAs are abundantly present in the respiratory tract of cotton rats (Sigmodon hispidus). Thus, we hypothesized that cotton rats could be a potential model for EV-D68 infection. Here, we evaluated the ability of two recently isolated EV-D68 strains (VANBT/1 and MO/14/49), along with the historical prototype Fermon strain (ATCC), to infect cotton rats. We found that cotton rats are permissive to EV-D68 infection without virus adaptation. The different strains of EV-D68 showed variable infection profiles and the ability to produce neutralizing antibody (NA) upon intranasal infection or intramuscular immunization. Infection with the VANBT/1 resulted in significant induction of pulmonary cytokine gene expression and lung pathology. Intramuscular immunization with live VANBT/1 or MO/14/49 induced strong homologous antibody responses, but a moderate heterologous NA response. We showed that passive prophylactic administration of serum with high content of NA against VANBT/1 resulted in an efficient antiviral therapy. VANBT/1-immunized animals showed complete protection from VANBT/1 challenge, but induced strong pulmonary Th1 and Th2 cytokine responses and enhanced lung pathology, indicating the generation of exacerbated immune response by immunization. In conclusion, our data illustrate that the cotton rat is a powerful animal model that provides an experimental platform to investigate pathogenesis, immune response, anti-viral therapies and vaccines against EV-D68 infection.

A Decrease in Temperature and Humidity Precedes Human Rhinovirus Infections in a Cold Climate

Both temperature and humidity may independently or jointly contribute to the risk of human rhinovirus (HRV) infections, either through altered survival and spread of viruses in the environment or due to changes in host susceptibility. This study examined the relationship between short-term variations in temperature and humidity and the risk of HRV infections in a subarctic climate. We conducted a case-crossover study among conscripts (n = 892) seeking medical attention due to respiratory symptoms during their military training and identified 147 HRV cases by real-time PCR. An average temperature, a decline in daily ambient temperature and absolute humidity (AH) during the three preceding days of the onset (hazard period) and two reference periods (a week prior and after the onset) were obtained. The average daily temperature preceding HRV infections was −9.9 ± 4.9 °C and the average AH was 2.2 ± 0.9 g/m³. An average (odds ratios (OR) 1.07 (95% confidence interval (CI) 1.00–1.15)) and maximal (OR 1.08 (1.01–1.17)) change in temperature increased the risk of HRV infections by 8% per 1 °C decrease. An average (OR 1.20 (CI 1.03–1.40)) and maximal decrease (OR 1.13 (CI 0.96–1.34)) in AH increased the risk of HRV infection by 13% and 20% per 0.5 g/m³ decrease. A higher average temperature during the three preceding days was positively associated with HRV infections (OR 1.07 (CI 1.00–1.15)). A decrease rather than low temperature and humidity per se during the preceding few days increases the risk of HRV infections in a cold climate. The information is applicable to populations residing in cold climates for appropriate personal protection and prevention of adverse health effects.

Enterovirus D68 and Human Respiratory Infections

Enterovirus D68 (EV-D68) is a member of the species Enterovirus D in the genus Enterovirus of the Picornaviridae family. EV-D68 was first isolated in the United States in 1962 and is primarily an agent of respiratory disease. Infections with EV-D68 have been rarely reported until recently, when reports of EV-D68 associated with respiratory disease increased notably worldwide. An outbreak in 2014 in the United States, for example, involved more than 1,000 cases of severe respiratory disease that occurred across almost all states. Phylogenetic analysis of all EV-D68 sequences indicates that the circulating strains of EV-D68 can be classified into two lineages, lineage 1 and lineage 2. In contrast to the prototype Fermon strain, all circulating strains have deletions in their genomes. Respiratory illness associated with EV-D68 infection ranges from mild illness that just needs outpatient service to severe illness requiring intensive care and mechanical ventilation. To date, there are no specific medicines and vaccines to treat or prevent EV-D68 infection. This review provides a detailed overview about our current understanding of EV-D68-related virology, epidemiology and clinical syndromes, pathogenesis, and laboratory diagnostics.

Global emergence of enterovirus D68: a systematic review

Since its discovery in California in 1962, reports of enterovirus D68 have been infrequent. Before 2014, infections were confirmed in only 699 people worldwide. In August, 2014, two paediatric hospitals in the USA reported increases in the number of patients with severe respiratory illness, with an over-representation in children with asthma. Shortly after, the authorities recognised a nationwide outbreak, which then spread to Canada, Europe, and Asia. In 2014, more than 2000 cases of enterovirus D68 were reported in 20 countries. Concurrently, clusters of children with acute flaccid paralysis of unknown cause were reported in several US states and in Europe. Enterovirus D68 infection was confirmed in some of the paralysed children, but not all. Complications in patients who were severely neurologically affected resemble those caused by poliomyelitis. In this paper we systematically review reports on enterovirus D68 to estimate its global epidemiology and its ability to cause respiratory infections and neurological damage in children. We extracted data from 70 papers to report on prevalence, symptoms, hospitalisation and mortality, and complications of enterovirus D68, both before and during the large outbreak of 2014. The magnitude and severity of the enterovirus D68 outbreak underscores a need for improved diagnostic work-up of paediatric respiratory illness, not only to prevent unnecessary use of antibiotics, but also to ensure better surveillance of diseases. Existing surveillance systems should be assessed in terms of capacity and ability to detect and report any upsurge of respiratory viruses such as enterovirus D68 in a timely manner, and focus should be paid to development of preventive measures against these emerging enteroviruses that have potential for severe disease.

Clinical differences between respiratory viral and bacterial mono- and dual pathogen detected among Singapore military servicemen with febrile respiratory illness

Background

Although it is known that febrile respiratory illnesses (FRI) may be caused by multiple respiratory pathogens, there are no population-level studies describing its impact on clinical disease.

Methods

Between May 2009 and October 2012, 7733 FRI patients and controls in the Singapore military had clinical data and nasal wash samples collected prospectively and sent for PCR testing. Patients with one pathogen detected (mono-pathogen) were compared with those with two pathogens (dual pathogen) for differences in basic demographics and clinical presentation.

Results

In total, 45.8% had one pathogen detected, 20.2% had two pathogens detected, 30.9% had no pathogens detected, and 3.1% had more than two pathogens. Multiple pathogens were associated with recruits, those with asthma and non-smokers. Influenza A (80.0%), influenza B (73.0%) and mycoplasma (70.6%) were most commonly associated with mono-infections, while adenovirus was most commonly associated with dual infections (62.9%). Influenza A paired with S. pneumoniae had higher proportions of chills and rigors than their respective mono-pathogens (P = 0.03, P = 0.009). H. influenzae paired with either enterovirus or parainfluenzae had higher proportions of cough with phlegm than their respective mono-pathogens. Although there were observed differences in mean proportions of body temperature, nasal symptoms, sore throat, body aches and joint pains between viral and bacterial mono-pathogens, there were few differences between distinct dual-pathogen pairs and their respective mono-pathogen counterparts.

Conclusion

A substantial number of FRI patients have multiple pathogens detected. Observed clinical differences between patients of dual pathogen and mono-pathogen indicate the likely presence of complex microbial interactions between the various pathogens.

Sequencing ebola and marburg viruses genomes using microarrays

Periodic outbreaks of Ebola and Marburg hemorrhagic fevers have occurred in Africa over the past four decades with case fatality rates reaching as high as 90%. The latest Ebola outbreak in West Africa in 2014 raised concerns that these infections can spread across continents and pose serious health risks. Early and accurate identification of the causative agents is necessary to contain outbreaks. In this report, we describe sequencing-by-hybridization (SBH) technique using high density microarrays to identify Ebola and Marburg viruses. The microarrays were designed to interrogate the sequences of entire viral genomes, and were evaluated with three species of Ebolavirus (Reston, Sudan, and Zaire), and three strains of Marburgvirus (Angola, Musoke, and Ravn). The results showed that the consensus sequences generated with four or more hybridizations had 92.1-98.9% accuracy over 95-99% of the genomes. Additionally, with SBH microarrays it was possible to distinguish between different strains of the Lake Victoria Marburgvirus. J. Med. Virol. 88:1303-1308, 2016. © 2016 Wiley Periodicals, Inc.

Molecular Evolution and Intraclade Recombination of Enterovirus D68 during the 2014 Outbreak in the United States

In August 2014, an outbreak of enterovirus D68 (EV-D68) occurred in North America, causing severe respiratory disease in children. Due to a lack of complete genome sequence data, there is only a limited understanding of the molecular evolution and epidemiology of EV-D68 during this outbreak, and it is uncertain whether the differing clinical manifestations of EV-D68 infection are associated with specific viral lineages. We developed a high-throughput complete genome sequencing pipeline for EV-D68 that produced a total of 59 complete genomes from respiratory samples with a 95% success rate, including 57 genomes from Kansas City, MO, collected during the 2014 outbreak. With these data in hand, we performed phylogenetic analyses of complete genome and VP1 capsid protein sequences. Notably, we observed considerable genetic diversity among EV-D68 isolates in Kansas City, manifest as phylogenetically distinct lineages, indicative of multiple introductions of this virus into the city. In addition, we identified an intersubclade recombination event within EV-D68, the first recombinant in this virus reported to date. Finally, we found no significant association between EV-D68 genetic variation, either lineages or individual mutations, and a variety of demographic and clinical variables, suggesting that host factors likely play a major role in determining disease severity. Overall, our study revealed the complex pattern of viral evolution within a single geographic locality during a single outbreak, which has implications for the design of effective intervention and prevention strategies.

IMPORTANCE

Until recently, EV-D68 was considered to be an uncommon human pathogen, associated with mild respiratory illness. However, in 2014 EV-D68 was responsible for more than 1,000 disease cases in North America, including severe respiratory illness in children and acute flaccid myelitis, raising concerns about its potential impact on public health. Despite the emergence of EV-D68, a lack of full-length genome sequences means that little is known about the molecular evolution of this virus within a single geographic locality during a single outbreak. Here, we doubled the number of publicly available complete genome sequences of EV-D68 by performing high-throughput next-generation sequencing, characterized the evolutionary history of this outbreak in detail, identified a recombination event, and investigated whether there was any correlation between the demographic and clinical characteristics of the patients and the viral variant that infected them. Overall, these results will help inform the design of intervention strategies for EV-D68.

Clinical severity of pediatric respiratory illness with enterovirus D68 compared with rhinovirus or other enterovirus genotypes

BACKGROUND

Enterovirus D68 (EV-D68) resulted in a reported increase in the number of children needing hospital or critical care admission because of respiratory insufficiency during 2014. It remains unclear, however, whether EV-D68 infections were more severe than rhinovirus or non-EV-D68 enterovirus infections.

METHODS

We evaluated consecutive children presenting to a pediatric hospital between Aug. 1 and Oct. 31, 2014, with positive nasopharyngeal swabs for rhinovirus or enterovirus that were sent automatically for EV-D68 testing. We compared characteristics and outcomes of patients with EV-D68 with those with rhinovirus or non-EV-D68 enterovirus in a matched cohort study.

RESULTS

A total of 93/297 (31.3%) of rhinovirus or enterovirus samples tested positive for EV-D68, and it was possible to compare 87 matched pairs. Children with EV-D68 infection were more likely to have difficulty breathing (odds ratio [OR] 3.00, 95% confidence interval [CI] 1.47-6.14). There was no significant difference in admission to the critical care unit or death among children with EV-D68 infection compared with those with other rhinovirus or enterovirus infections (adjusted OR 1.47, 95% CI 0.61-3.52). Children with EV-D68 infection were more often admitted to hospital, but not significantly so (adjusted OR 2.29, 95% CI 0.96-5.46).

INTERPRETATION

Enterovirus D68 seems to be a more virulent pulmonary pathogen than rhinovirus or non-EV-D68 enterovirus, but we did not find a significant difference in death or need for critical care.

Elevated transmission of upper respiratory illness among new recruits in military barracks in Thailand

BACKGROUND

New recruits within military barracks present conditions favorable for the spread of respiratory pathogens. However, respiratory pathogen transmission in such confined settings in the tropics has not been well studied.

METHODS

Recruits in four successive Royal Thai Army basic training classes living in military barracks were monitored for the symptoms of influenza-like illness (ILI) or upper respiratory illness (URI). Classes 1 and 2 were also monitored after basic training. Nasal/throat swabs from acute illnesses were collected and tested by influenza RT-PCR (all four classes). In addition, class 1 had multiplex PCR performed along with the analysis of bed locations within the barracks.

RESULTS

Influenza-like illness/upper respiratory illness rates ranged from 4·7 to 6·9 per 100 recruit-weeks in the four classes and generally decreased during the course of basic training (P < 0·05 in three of four classes). Rates during basic training were 1·7 (95% CI: 1·29, 2·29) and 2·5 (95% CI: 1·5, 4·1) times higher than after basic training (classes 1 and 2, respectively). In class 1, coronavirus, parainfluenza virus, and rhinovirus were the most commonly identified respiratory pathogens; only one influenza PCR-positive infection was detected in all four classes. Bed locations of URI/ILI cases in class 1 tended to be in closer proximity to each other.

CONCLUSION

Basic training recruits in military barracks in the tropics had high rates of acute respiratory illnesses with illness patterns consistent with external seeding followed by substantial internal transmission. Our findings may contribute to control measures in similar confined settings both within and outside the military.

Changes in Clinical Presentation and Epidemiology of Respiratory Pathogens Associated With Acute Respiratory Illness in Military Trainees After Reintroduction of Adenovirus Vaccine

Background.  Adenovirus (Ad) has long been the predominant cause of acute respiratory illness (ARI) in military trainees. In 2011, live oral Ad vaccines for serotypes 4 and 7 were reintroduced into US basic military training populations. This study evaluated the impact on clinical presentations and other respiratory pathogens. Methods.  The Center for Advanced Molecular Detection at Joint Base San Antonio-Lackland prospectively collects demographic, clinical, and polymerase chain reaction data from respiratory specimens (throat swab and nasal wash) among Air Force trainees presenting for care of ARI. Results.  From June 2008 to August 2013, 2660 trainees enrolled and were tested for selected respiratory pathogens. Post-vaccine introduction (VI), reported systemic symptoms were less frequent, including fever (38% vs 94%) and myalgia (37% vs 67%; P < .01). Median temperature and heart rate decreased (98.4 vs 101.3°F, 81 vs 96 beats per minute; P < .01). Ad detection decreased for all Ad (3% vs 68%), Ad4 (1% vs 70%), 7 (0% vs 8%), 14 (0% vs 5%), and 3 (0.1% vs 2%); P < .01). Rhinovirus and cases with no pathogen identified increased in frequency (35% vs 18%, 51% vs 14%; P < .01). Conclusions.  Acute respiratory illness in military trainees post-VI is associated with decreased severity of systemic symptoms and reduced fever and heart rate. Marked reductions in frequency of Ad serotypes are seen, including those in the vaccine, with no serotype shift. However, detection of several other respiratory pathogens, most notably rhinovirus, is observed in increasing proportions, and a majority are now undiagnosed clinical syndromes.

Risk factors for febrile respiratory illness and mono-viral infections in a semi-closed military environment: a case-control study

Background

Febrile respiratory illness (FRI) results in substantial burden in semi-closed environments. Tackling risk factors may reduce transmission and infection. However, risk factors involved in one setting may not be generalizable in all settings due to differences in climate, residential environment, population genetic and cultural backgrounds. This study aims to identify risk factors of FRI and mono-viral infections in a tropical military environment.

Methods

From year 2009 to 2012, military personnel with temperature ≥37.5 °C, cough and/or sore throat, and personnel with no fever or no respiratory symptoms were recruited as cases and controls, respectively. Subjects provided nasal wash specimens and answered a standardized questionnaire. Resplex assays were used to determine the viral etiologies. Descriptive, univariate and multivariate analyses of the variables were performed using appropriate descriptive tests and logistic regression modelling, respectively, with R program.

Results

A total of 7,743 FRI cases and 1,247 non-FRI study controls were recruited. Increasing age [adjusted odds ratio (AOR) = 1.03; 95 % confidence interval (CI) = 1.01-1.05], recruit camp (AOR = 4.67; 95 % CI = 3.99-5.46) and smoker (AOR = 1.31; 95 % CI = 1.13-1.52) were independent risk factors of FRI. Malay ethnicity was positively associated with influenza A(H1N1)pdm09 (AOR = 1.50; 95 % CI = 1.04-2.15) and coxsackie/echovirus (AOR = 1.67; 95 % CI = 1.19-2.36) mono-infection. Significant contact risk factors were stay-out personnel with ill household member (AOR = 4.96; 95 % CI = 3.39-7.24), and stay-in personnel with ill bunkmate and household member (AOR = 3.55; 95 % CI = 2.57-4.91). Staying in camp with none ill in bunk and at home was a protective factor against FRI (AOR = 0.80; 95 % CI = 0.64-0.99). These contact risk factors were similarly observed for the five most common viruses detected, namely adenovirus, rhinoviruses, influenza A and B, and coxsackie/echovirus.

Conclusion

Increasing age, smoker, recruit-camp, stay-out personnel with ill household members and stay-in personnel with ill bunkmates were independent risk factors of FRI in a semi-closed military environment. Early identification and isolation of ill personnel from their bunk may be effective to prevent and reduce transmission and disease burden.

Molecular epidemiology of enterovirus D68 from 2013 to 2014 in Philippines

Enterovirus D68 (EV-D68) has been recognized as an important cause of acute respiratory infections. Here we report the molecular epidemiology of EV-D68 in Philippines from 2013 to 2014; we found cases in areas affected by Typhoon Haiyan and found new strains in the country.

Global reemergence of enterovirus D68 as an important pathogen for acute respiratory infections

We previously detected enterovirus D68 (EV-D68) in children with severe acute respiratory infections in the Philippines in 2008-2009. Since then, the detection frequency of EV-D68 has increased in different parts of the world, and EV-D68 is now recognized as a reemerging pathogen. However, the epidemiological profile and clinical significance of EV-D68 is yet to be defined, and the virological characteristics of EV-D68 are not fully understood. Recent studies have revealed that EV-D68 is detected among patients with acute respiratory infections of differing severities ranging from mild upper respiratory tract infections to severe pneumonia including fatal cases in pediatric and adult patients. In some study sites, the EV-D68 detection rate was higher among patients with lower respiratory tract infections than among those with upper respiratory tract infections, suggesting that EV-D68 infections are more likely to be associated with severe respiratory illnesses. EV-D68 strains circulating in recent years have been divided into three distinct genetic lineages with different antigenicity. However, the association between genetic differences and disease severity, as well as the occurrence of large-scale outbreaks, remains elusive. Previous studies have revealed that EV-D68 is acid sensitive and has an optimal growth temperature of 33 °C. EV-D68 binds to α2,6-linked sialic acids; hence, it is assumed that it has an affinity for the upper respiratory track where these glycans are present. However, the lack of suitable animal model constrains comprehensive understanding of the pathogenesis of EV-D68.

Respiratory tract infections in the military environment

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Soldiers in combat zones are at risk of contracting respiratory infections.

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Troops deployed to the harsh environment have high rates of respiratory symptoms.

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Over 40% of soldiers’ respiratory illnesses have been due to unknown causative agents.

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Limited diagnostic capabilities make it difficult to estimate the number of cases.

Military personnel fighting in contemporary battlefields as well as those participating in combat training are at risk of contracting respiratory infections. Epidemiological studies have demonstrated that soldiers deployed to the harsh environment have higher rates of newly reported respiratory symptoms than non-deployers. Acute respiratory diseases are the principle reason for outpatient treatment and hospitalization among military personnel, with an incidence exceeding that of the adult civilian population by up to three-fold. Adenoviruses, influenza A and B viruses, Streptococcus pneumoniae, Streptococcus pyogenes, coronaviruses and rhinoviruses have been identified as the main causes of acute respiratory infections among the military population. Although infective pathogens have been extensively studied, a significant proportion of illnesses (over 40%) have been due to unknown causative agents. Other health hazards, which can lead to respiratory illnesses among troops, are extreme air temperatures, desert dust, emissions from burn pits, industrial pollutants, and airborne contaminants originating from degraded soil. Limited diagnostic capabilities, especially inside the area of operations, make it difficult to accurately estimate the exact number of respiratory diseases in the military environment. The aim of the study was to discuss the occurrence of respiratory tract infections in army personnel, existing risk factors and preventive measures.

Respiratory viral pathogens among Singapore military servicemen 2009-2012: epidemiology and clinical characteristics

Background

Few studies have comprehensively described tropical respiratory disease surveillance in military populations. There is also a lack of studies comparing clinical characteristics of the non-influenza pathogens with influenza and amongst themselves.

Methods

From May 2009 through October 2012, 7733 consenting cases of febrile respiratory illness (FRI) (temperature [greater than or equal to]37.5degreesC with cough or sorethroat) and controls in the Singapore military had clinical data and nasal washes collected prospectively. Nasal washes underwent multiplex PCR, and the analysis was limited to viral mono-infections.

Results

49% of cases tested positive for at least one virus, of whom 10% had multiple infections. 53% of the FRI cases fulfilled the definition of influenza-like illness (ILI), of whom 52% were positive for at least one virus. The most frequent etiologies for mono-infections among FRI cases were Influenza A(H1N1)pdm09 (13%), Influenza B (13%) and coxsackevirus (9%). The sensitivity, specificity, positive predictive value and negative predictive value of ILI for influenza among FRI cases were 72%, 48%, 40% and 69% respectively. On logistic regression, there were marked differences in the prevalence of different symptoms and signs between viruses with fever more prevalent amongst influenza and adenovirus infections than other viruses.

Conclusion

There are multiple viral etiologies for FRI and ILI with differing clinical symptoms in the Singapore military. Influenza and coxsackevirus were the most common etiology for FRI, while influenza and adenoviruses displayed the most febrile symptoms. Further studies should explore these differences and possible interventions.

Environmental factors, immune changes and respiratory diseases in troops during military activities

Combat operations in contemporary theaters of war, as well as combat training, are carried out in all parts of the world, typically in a harsh environment. Specific environmental conditions, such as heat, cold, high-altitudes, desert climates, as well as chemical and biological pollution of both the atmosphere and soil, together with over-exertion, food restrictions, sleep deprivation, and psychological stress can all result in changes in the immune system and the occurrence of associated diseases. Respiratory diseases are one of the most common health problems among military personnel participating in combat training or deployed to operations in areas characterized by difficult climatic and sanitary conditions. They are, therefore, one of the main reasons for military personnel requiring ambulant and hospital treatment. The aim of the study was to discuss the influence of environmental factors and the conditions in which active duty is performed on changes in the immune system and the occurrence of respiratory tract diseases in a military environment.

Respiratory virus shedding in a cohort of on-duty healthcare workers undergoing prospective surveillance

BACKGROUND

Healthcare-associated transmission of respiratory viruses is a concerning patient safety issue.

DESIGN

Surveillance for influenza virus among a cohort of healthcare workers (HCWs) was conducted in a tertiary care children's hospital from November 2009 through April 2010 using biweekly nasal swab specimen collection. If a subject reported respiratory symptoms, an additional specimen was collected. Specimens from ill HCWs and a randomly selected sample from asymptomatic subjects were tested for additional respiratory viruses by multiplex polymerase chain reaction (PCR).

RESULTS

A total of 1,404 nasal swab specimens were collected from 170 enrolled subjects. Influenza circulated at very low levels during the surveillance period, and 74.2% of subjects received influenza vaccination. Influenza virus was not detected in any specimen. Multiplex respiratory virus PCR analysis of all 119 specimens from symptomatic subjects and 200 specimens from asymptomatic subjects yielded a total of 42 positive specimens, including 7 (16.7%) in asymptomatic subjects. Viral shedding was associated with report of any symptom (odds ratio [OR], 13.06 [95% confidence interval, 5.45-31.28]; [Formula: see text]) and younger age (OR, 0.96 [95% confidence interval, 0.92-0.99]; [Formula: see text]) when controlled for sex and occupation of physician or nurse. After the surveillance period, 46% of subjects reported working while ill with an influenza-like illness during the previous influenza season.

CONCLUSIONS

In this cohort, HCWs working while ill was common, as was viral shedding among those with symptoms. Asymptomatic viral shedding was infrequent but did occur. HCWs should refrain from patient care duties while ill, and staffing contingencies should accommodate them.

Application of resequencing microarrays in microbial detection and characterization

Microarrays are powerful, highly parallel assays that are transforming microbiological diagnostics and research. The adaptation of microarray-based resequencing technology for microbial detection and characterization resulted in the development of a number assays that have unique advantages over other existing technologies. This technological platform seems to be especially useful for sensitive and high-resolution multiplexed diagnostics for clinical syndromes with similar symptoms, screening environmental samples for biothreat agents, as well as genotyping and whole-genome analysis of single pathogens.

Acute respiratory infections due to enterovirus 68 in Yamagata, Japan between 2005 and 2010

To clarify the epidemiology of enterovirus 68 (EV68), which is one of the most rarely identified enteroviruses, virus isolation and molecular screening using RT-PCR was performed on 6307 respiratory specimens collected at pediatric clinics in Yamagata, Japan between 2005 and 2010. In the years 2005-2009, 10, 1, 2, 0, and 2 (40) EV68-positive cases, respectively, were identified by RT-PCR. In 2010, 40 cases were identified altogether: 2 by isolation only, 26 by RT-PCR only, and 12 by both isolation and RT-PCR. Phylogenetic analysis indicated that plural genetically distinct clusters co-circulated. These results suggest that that difficulty in EV68 isolation leads to an underestimation of the prevalence of EV68 infections.

Worldwide emergence of multiple clades of enterovirus 68

Human enterovirus 68 (EV-D68) is a historically rarely reported virus linked with respiratory disease. In the past 3 years, a large increase in respiratory disease associated with EV-D68 has been reported, with documented outbreaks in North America, Europe and Asia. In several outbreaks, genetic differences were identified among the circulating strains, indicating the presence of multiple clades. In this report, we analyse archived and novel EV-D68 strains from Africa and the USA, obtained from patients with respiratory illness. Phylogenetic analysis of all EV-D68 sequences indicates that, over the past two decades, multiple clades of the virus have emerged and spread rapidly worldwide. All clades appear to be currently circulating and contributing to respiratory disease.

Increased risk of noninfluenza respiratory virus infections associated with receipt of inactivated influenza vaccine

We randomized 115 children to trivalent inactivated influenza vaccine (TIV) or placebo. Over the following 9 months, TIV recipients had an increased risk of virologically-confirmed non-influenza infections (relative risk: 4.40; 95% confidence interval: 1.31-14.8). Being protected against influenza, TIV recipients may lack temporary non-specific immunity that protected against other respiratory viruses.

Outbreak of lower respiratory tract illness associated with human enterovirus 68 among American Indian children

Human enterovirus 68 (EV68) infections are rarely reported. We describe a respiratory outbreak associated with EV68 among 18 children admitted to a remote Indian Health Service facility during August 11, 2010 through September 14, 2010. Clinical illness was characterized by pneumonia and wheezing. EV68 should be considered as an etiology in outbreaks of lower respiratory tract illness.

Clinical characteristics and genetic variability of human rhinovirus in Mexico

Human rhinovirus (HRV) is a leading cause of acute respiratory infection (ARI) in young children and infants worldwide and has a high impact on morbidity and mortality in this population. Initially, HRV was classified into two species: HRV-A and HRV-B. Recently, a species called HRV-C and possibly another species, HRV-D, were identified. In Mexico, there is little information about the role of HRV as a cause of ARI, and the presence and importance of species such as HRV-C are not known. The aim of this study was to determine the clinical characteristics and genetic variability of HRV in Mexican children. Genetic characterization was carried out by phylogenetic analysis of the 5'-nontranslated region (5'-NTR) of the HRV genome. The results show that the newly identified HRV-C is circulating in Mexican children more frequently than HRV-B but not as frequently as HRV-A, which was the most frequent species. Most of the cases of the three species of HRV were in children under 2 years of age, and all species were associated with very mild and moderate ARI.

Emergence and epidemic occurrence of enterovirus 68 respiratory infections in The Netherlands in 2010

Following an increase in detection of enterovirus 68 (EV68) in community surveillance of respiratory infections in The Netherlands in 2010, epidemiological and virological analyses were performed to investigate the possible public health impact of EV68 infections. We retrospectively tested specimens collected from acute respiratory infections surveillance and through three children cohort studies conducted in The Netherlands from 1994 through 2010. A total of 71 of 13,310 (0.5%) specimens were positive for EV68, of which 67 (94%) were from symptomatic persons. Twenty-four (34%) of the EV68 positive specimens were collected during 2010. EV68-positive patients with respiratory symptoms showed significantly more dyspnea, cough and bronchitis than EV68-negative patients with respiratory symptoms. Phylogenetic analysis showed an increased VP1 gene diversity in 2010, suggesting that the increased number of EV68 detections in 2010 reflects a real epidemic. Clinical laboratories should consider enterovirus diagnostics in the differential diagnosis of patients presenting with respiratory symptoms.

Enterovirus 68 among children with severe acute respiratory infection, the Philippines

Enterovirus 68 (EV68) is a rare enterovirus associated with respiratory illness that, unlike other enteroviruses, has been identified only from respiratory specimens. We identified EV68 from respiratory specimens of children hospitalized with a diagnosis of severe pneumonia in Leyte, Republic of the Philippines. Twenty-one samples showed high similarity with EV68 by sequencing of 5' nontranslated region; 17 of these samples were confirmed as EV68 by sequencing of viral protein 1 capsid coding region. Most previously reported EV68 cases had been identified as sporadic cases. All 21 patients we identified had severe illness, and 2 died, possibly the first reported fatal cases associated with EV68 infection. Our study suggests that EV68 may be a possible causative agent of severe respiratory illnesses.

Viral interference induced by live attenuated virus vaccine (OPV) can prevent otitis media

Background

The goal of this study was to evaluate whether a live attenuated poliovirus vaccine (OPV) has clinically relevant interfering effect with non-polio infections causing otitis media in young children.

Methods

Open trial in which the intervention group (64 children) received OPV at the age of 2, 3, 6 and 12 months. The control group (250 children) received IPV (inactivated polio vaccine) at the age of 6 and 12 months. Clinical symptoms were recorded by a questionnaire at the age of 3, 6, 12, 18 and 24 months.

Results

Otitis media episodes were less frequent in the OPV than in the control group. A significant difference was seen at the age of 6–18 months (IRR = 0.76 [95% CI 0.59–0.94], P = 0.011) and was particularly clear among children, who attended daycare (IRR 0.37 [95% CI 0.19–0.71], P = 0.003).

Conclusions

OPV provides some protection against otitis media. This effect may be mediated by viral interference with non-polio viruses.