Retrospective analysis of demographic and clinical factors associated with etiology of febrile respiratory illness among US military basic trainees

Diagnostic and Therapeutic Challenges in a Military Recruit Training Center of the Hellenic Navy: A Retrospective Analysis of the Poros Registry Serving as a Quality Improvement Project for Medical Officers

INTRODUCTION

Basic military training (BMT) has been associated with increased morbidity burden. Nevertheless, the exact epidemiology of the encountered cases in the BMT of Greek recruits has never been assessed. The aim of this quality improvement project was to investigate for the first time the clinical patterns, rates, and severity of symptoms leading recruits to visit the infirmary of a recruit training center and use this knowledge to provide a practical guidance for the physicians in charge.

MATERIALS AND METHODS

All medical cases which were consecutively examined for the time range from November 2021 to September 2022 at the infirmary of the Hellenic Naval recruit training center in Poros, Greece, were retrospectively analyzed. Logistic regression analyses were performed to identify independent predictors of "severe clinical status" (i.e., overnight sick bay confinement and/or transfer to a tertiary hospital within 24 h) and absence from BMT for at least 1 day.

RESULTS

A total of 2,623 medical cases were examined during four recruit seasons from November 2021 to September 2022. Upper respiratory tract infections (URTIs) and musculoskeletal injuries were the most frequent reasons for a recruit's visit to the infirmary (33.9% and 30.2%, respectively). 6.7% of the total cases were identified as having "severe clinical status." Specifically, in psychiatric, urological, and cardiovascular cases, febrile events were all independently associated with increased risk of "severe clinical status." There was a positive association between training week and absence from BMT, while febrile events and spring recruit season were also independently linked with increased probability of absence from BMT for at least 1 day.

CONCLUSIONS

URTIs and musculoskeletal complaints were the primary reasons for recruits' presentation at the infirmary of a Greek recruit training center, leading to severe rates of attrition. Further registries and quality improvement projects are warranted to reach specific conclusions and reduce BMT-related morbidity and its subsequent implications.

Risk Evaluation and Mitigation Strategies for Potential Outbreaks of Adenovirus Infection: Evidence From the Recent Incidences in West Bengal, India

Recent outbreaks of highly virulent and pathogenic viruses such as COVID-19, monkeypox, and Nipah virus have prompted global concerns. Another threat has emerged in West Bengal, India, in the form of Human Adenovirus (HAdV), particularly affecting children and immunocompromised individuals. The DNA virus HAdV can cause respiratory, liver, renal, and neurological issues. Politically unstable areas with military and medical camps and refugee communities are at risk because they spread in densely populated areas. Due to its rapid mutation and dissemination, the virus represents a global threat. Although scientists have developed vaccines for specific serotypes of HAdV, their primary application is limited to military contexts. Antiviral and immunotherapy research is continuing, but treatment choices are limited. Public awareness programs and hygiene measures are essential to preventing a global pandemic. Governments should invest in healthcare infrastructure and diagnostics, and researchers should focus on developing vaccines and therapies. The West Bengal outbreak is a clear reminder that governments, healthcare professionals, and researchers must work together to control and prevent HAdV. To effectively comprehend and address this rising viral threat, it is imperative to engage in further research and documentation.

Adenovirus: Epidemiology, Global Spread of Novel Types, and Approach to Treatment

Adenoviruses (AdVs) are DNA viruses that typically cause mild infections involving the upper or lower respiratory tract, gastrointestinal tract, or conjunctiva. Rare manifestations of AdV infections include hemorrhagic cystitis, hepatitis, hemorrhagic colitis, pancreatitis, nephritis, or meningoencephalitis. AdV infections are more common in young children, due to lack of humoral immunity. Epidemics of AdV infection may occur in healthy children or adults in closed or crowded settings (particularly military recruits). The vast majority of cases are self-limited. However, the clinical spectrum is broad and fatalities may occur. Dissemination is more likely in patients with impaired immunity (e.g., organ transplant recipients, human immunodeficiency virus infection). Fatality rates for untreated severe AdV pneumonia or disseminated disease may exceed 50%. More than 100 genotypes and 52 serotypes of AdV have been identified and classified into seven species designated HAdV-A through -G. Different types display different tissue tropisms that correlate with clinical manifestations of infection. The predominant types circulating at a given time differ among countries or regions, and change over time. Transmission of novel strains between countries or across continents and replacement of dominant viruses by new strains may occur. Treatment of AdV infections is controversial, as prospective, randomized therapeutic trials have not been done. Cidofovir has been the drug of choice for severe AdV infections, but not all patients require treatment. Live oral vaccines are highly efficacious in reducing the risk of respiratory AdV infection and are in routine use in the military in the United States but currently are not available to civilians.

Breakfast Skipping Is Associated with Vitamin D Deficiency among Young Adults entering Initial Military Training

BACKGROUND

Vitamin D deficiency (VDD), defined as serum 25-hydroxyvitamin D (25[OH]D) levels < 20 ng/mL [to convert 25[OH]D ng/mL to nmol/L, multiply by 2.5]) is prevalent in young adults and has been associated with adverse health outcomes, including stress fracture during periods of increased physical activity such as military training. Foods commonly consumed at breakfast provide an important source of vitamin D, yet breakfast skipping is common among young adults. However, whether breakfast skipping is associated with VDD in young adults is unclear.

OBJECTIVES

This study aimed to determine whether breakfast skipping is associated with odds of VDD among recruits entering initial military training (IMT), and with changes in serum 25(OH)D during IMT. In addition, whether diet quality and vitamin D intake mediated these associations was determined.

DESIGN

Secondary analysis of individual participant data collected during five IMT studies. Breakfast skipping (≥ 3 times/week) was self-reported. Dietary intake was determined using food frequency questionnaires, and vitamin D status was assessed using circulating 25(OH)D concentrations pre- and post-IMT.

PARTICIPANTS AND SETTING

Participants were healthy US Army, US Air Force, and US Marine recruits (N = 1,569, 55% male, mean ± standard deviation age 21 ± 4 years) entering military service between 2010 and 2015 at Fort Jackson, SC; Fort Sill, OK; Lakeland Air Force Base, TX; or the Marine Corps Recruit Depot, Parris Island, SC.

MAIN OUTCOME MEASURES

Primary outcomes were VDD pre-IMT and change in 25(OH)D from pre- to post-IMT.

STATISTICAL ANALYSIS PERFORMED

Associations were determined using multivariate-adjusted logistic and linear regression and mediation models.

RESULTS

Forty-six percent of military recruits were classified as breakfast skippers pre-IMT, and 30% were VDD. Breakfast skipping was associated with a higher odds of pre-IMT VDD (odds ratio 1.5, 95% CI 1.1 to 1.9), and lower vitamin D intake and diet quality were partial mediators of the association. Serum 25(OH)D concentrations improved (P = 0.01) among habitual breakfast skippers versus nonskippers during IMT; however, regression to the mean could not be ruled out. Neither change in diet quality nor vitamin D intake were associated with change in 25(OH)D concentrations during IMT.

CONCLUSIONS

Breakfast skipping is prevalent among incoming military recruits and is associated with VDD. This relationship may be mediated by lower diet quality and vitamin D intake.

Respiratory Viral Pathogens Among U.S. Military Personnel at a Medical Treatment Facility in Hawaii From 2014 to 2019

INTRODUCTION

Acute respiratory diseases account for a substantial number of outpatient visits and hospitalizations among U.S. military personnel, significantly affecting mission readiness and military operations. We conducted a retrospective analysis of respiratory viral pathogen (RVP) samples collected from U.S. military personnel stationed in Hawaii and tested at Tripler Army Medical Center from January 2014 to May 2019 in order to describe the etiology, distribution, and seasonality of RVP exposure in a military population.

MATERIALS AND METHODS

Samples were analyzed by viral culture or multiplex PCR. Distribution of respiratory viruses over time was analyzed as well as subject demographic and encounter data. Presenting signs and symptoms were evaluated with each RVP.

RESULTS

A total of 2,576 military personnel were tested, of which 726 (28.2%) were positive for one or more RVP. Among positive tests, the three most common viral pathogens detected were influenza A (43.0%), rhinovirus (24.5%), and parainfluenza (7.6%). Symptoms were generally mild and most frequently included cough, fever, and body aches.

CONCLUSION

Our study evaluated respiratory virus prevalence, seasonality, and association with clinical symptoms for military personnel in an urban tropical setting in Oahu, HI, over a 5-year period. We show that viral prevalence and seasonality in Hawaii are distinct from those of the CONUS. Results contribute to the broader understanding of seasonality, clinical manifestation, and demographics of RVP among active duty military personnel stationed in Hawaii.

The Acute Respiratory Infection Consortium: A Multi-Site, Multi-Disciplinary Clinical Research Network in the Department of Defense

Introduction

Acute respiratory infections (ARI) result in substantial annual morbidity among military personnel and decrease operational readiness. Herein, we summarize the research efforts of the Infectious Disease Clinical Research Program (IDCRP) related to ARIs.

Methods

The ARI Research Area of the IDCRP was established in response to the 2009 emergence of pandemic influenza A/H1N1. That year, IDCRP investigators deployed the ARI Consortium Natural History Study (ARIC NHS), a multi-centered, longitudinal observational study to assess etiology, epidemiology, and clinical characteristics of influenza-like illness (ILI) and severe acute respiratory infections (SARI) in the U.S. military. The success of this initial effort spurred implementation of several new initiatives. These include the FluPlasma trial, designed to evaluate the efficacy of hyperimmune anti-influenza plasma for the treatment of severe influenza; the self-administered live-attenuated influenza vaccine (SNIF) trial, which assessed the immunogenicity and acceptance of a self-administered live-attenuated influenza vaccine in military personnel; the Study to Address Threats of ARI in Congregate Military Populations (ATARI), a prospective study of ILI transmission, etiology and epidemiology in recruits; and the Flu Breath Test (FBT) study, a preliminary study of exhaled volatile organic compounds (VOC) in influenza patients. In addition, the InFLUenza Patient-Reported Outcome (FLU-PRO) survey, a daily diary to measure influenza symptoms during clinical trials, was developed. Lastly, the Pragmatic Assessment of Influenza Vaccine Effectiveness in the DoD (PAIVED) study, a two-year randomized trial designed to compare the effectiveness of the three types of licensed vaccines, launched in Fall 2018.

Results

The on-going ARIC NHS has enrolled over 2000 ILI and SARI cases since its inception, providing data on burden and clinical manifestations of ARI in military personnel and their families. The FluPlasma 2 trial concluded subject enrollment in 2018. Preliminary results from ATARI study show a high frequency of respiratory viruses circulating during the first two weeks of recruit training. Based on assessment of FLU-PRO responses, which were found to be reliable and reproducible, the survey may be a useful tool in clinical trials and epidemiological studies. The Flu Breath Study will complete enrollment in 2019. Findings from PAIVED are intended to provide evidence needed for assessing influenza vaccination policy in the military.

Conclusions

The ARI burden in the armed services remains significant every year and the threat is dynamic given emergent and evolving threats, such as influenzas. With strong successes to date, future initiatives of the ARI Research Area will focus on interventional studies, ARI transmission dynamics in congregate military settings, and determinants of risk of pandemic influenza and other emergent respiratory viruses.

Human Adenovirus Type 55 Distribution, Regional Persistence, and Genetic Variability

Human adenovirus type 55 (HAdV-55) causes acute respiratory disease of variable severity and has become an emergent threat in both civilian and military populations. HAdV-55 infection is endemic to China and South Korea, but data from other regions and time periods are needed for comprehensive assessment of HAdV-55 prevalence from a global perspective. In this study, we subjected HAdV-55 isolates from various countries collected during 1969-2018 to whole-genome sequencing, genomic and proteomic comparison, and phylogenetic analyses. The results show worldwide distribution of HAdV-55; recent strains share a high degree of genomic homogeneity. Distinct strains circulated regionally for several years, suggesting persistent local transmission. Several cases of sporadic introduction of certain strains to other countries were documented. Among the identified amino acid mutations distinguishing HAdV-55 strains, some have potential impact on essential viral functions and may affect infectivity and transmission.

The molecular epidemiology of respiratory viruses in military trainees in Iran

Background: Military populations are more prone to respiratory infections worldwide. There is a dearth of research about the role of viral pathogens in the etiology of respiratory infections in military trainees in Iran. Hence, we aimed to investigate the molecular epidemiology and clinical symptoms of respiratory viruses among this population.

Methods: This cross-sectional study was performed on 400 military trainees with symptoms of respiratory infection, referred to the military medical clinic center in the basic military training camp of the General Staff of the Armed Forces of the Islamic Republic of Iran. Nucleic acid extraction from the throat or nasopharyngeal swab samples was performed by an automated extraction system. The extracts were then analyzed by the CLART® PneumoVir array system for the detection of respiratory viruses.

Results: All military trainees were male, aged between 18 and 57 years (mean: 21.69 years). Sore throat (75.5%), rhinorrhea (63.2%), cough (59.2%), fever (59.2%), and nasal congestion (50.5%) were amongst the most common symptoms. Overall, viral pathogens were detected in a total count of 124 (31%). The most commonly detected viruses were rhinovirus (7.2%), respiratory syncytial virus A (7.2%) and influenza B virus (6%).

Conclusion: This study was an important first step for understanding the etiological role of viral pathogens in respiratory infection among military trainees population in Iran. Our results indicated that rhinovirus, respiratory syncytial virus A and influenza B virus are important viral pathogens causing respiratory infection in military trainees, respectively. However, further multi-center studies with larger sample size are strongly recommended to confirm our findings.

Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenzaa

These clinical practice guidelines are an update of the guidelines published by the Infectious Diseases Society of America (IDSA) in 2009, prior to the 2009 H1N1 influenza pandemic. This document addresses new information regarding diagnostic testing, treatment and chemoprophylaxis with antiviral medications, and issues related to institutional outbreak management for seasonal influenza. It is intended for use by primary care clinicians, obstetricians, emergency medicine providers, hospitalists, laboratorians, and infectious disease specialists, as well as other clinicians managing patients with suspected or laboratory-confirmed influenza. The guidelines consider the care of children and adults, including special populations such as pregnant and postpartum women and immunocompromised patients.

Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenzaa

These clinical practice guidelines are an update of the guidelines published by the Infectious Diseases Society of America (IDSA) in 2009, prior to the 2009 H1N1 influenza pandemic. This document addresses new information regarding diagnostic testing, treatment and chemoprophylaxis with antiviral medications, and issues related to institutional outbreak management for seasonal influenza. It is intended for use by primary care clinicians, obstetricians, emergency medicine providers, hospitalists, laboratorians, and infectious disease specialists, as well as other clinicians managing patients with suspected or laboratory-confirmed influenza. The guidelines consider the care of children and adults, including special populations such as pregnant and postpartum women and immunocompromised patients.

Febrile Respiratory Illness Associated with Human Adenovirus Type 55 in South Korea Military, 2014-2016

An outbreak of febrile respiratory illness associated with human adenovirus (HAdV) occurred in the South Korea military during the 2014–15 influenza season and thereafter. Molecular typing and phylogenetic analysis of patient samples identified HAdV type 55 as the causative agent. Emergence of this novel HAdV necessitates continued surveillance in military and civilian populations.

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.

Adenovirus: Epidemiology, Global Spread of Novel Serotypes, and Advances in Treatment and Prevention

Adenoviruses (AdVs) are DNA viruses that typically cause mild infections involving the upper or lower respiratory tract, gastrointestinal tract, or conjunctiva. Rare manifestations of AdV infections include hemorrhagic cystitis, hepatitis, hemorrhagic colitis, pancreatitis, nephritis, or meningoencephalitis. AdV infections are more common in young children, due to lack of humoral immunity. Epidemics of AdV infection may occur in healthy children or adults in closed or crowded settings (particularly military recruits). The disease is more severe and dissemination is more likely in patients with impaired immunity (e.g., organ transplant recipients, human immunodeficiency virus infection). Fatality rates for untreated severe AdV pneumonia or disseminated disease may exceed 50%. More than 50 serotypes of AdV have been identified. Different serotypes display different tissue tropisms that correlate with clinical manifestations of infection. The predominant serotypes circulating at a given time differ among countries or regions, and change over time. Transmission of novel strains between countries or across continents and replacement of dominant viruses by new strains may occur. Treatment of AdV infections is controversial, as prospective, randomized therapeutic trials have not been conducted. Cidofovir is the drug of choice for severe AdV infections, but not all patients require treatment. Live oral vaccines are highly efficacious in reducing the risk of respiratory AdV infection and are in routine use in the military in the United States, but currently are not available to civilians.

Prediction of Peaks of Seasonal Influenza in Military Health-Care Data

Influenza is a highly contagious disease that causes seasonal epidemics with significant morbidity and mortality. The ability to predict influenza peak several weeks in advance would allow for timely preventive public health planning and interventions to be used to mitigate these outbreaks. Because influenza may also impact the operational readiness of active duty personnel, the US military places a high priority on surveillance and preparedness for seasonal outbreaks. A method for creating models for predicting peak influenza visits per total health-care visits (ie, activity) weeks in advance has been developed using advanced data mining techniques on disparate epidemiological and environmental data. The model results are presented and compared with those of other popular data mining classifiers. By rigorously testing the model on data not used in its development, it is shown that this technique can predict the week of highest influenza activity for a specific region with overall better accuracy than other methods examined in this article.

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.