Safety, efficacy, and immunogenicity of a replication-defective human cytomegalovirus vaccine, V160, in cytomegalovirus-seronegative women: a double-blind, randomised, placebo-controlled, phase 2b trial

BACKGROUND

A vaccine that prevents cytomegalovirus (CMV) infection in women could reduce the incidence of congenital CMV infection, a major cause of neurodevelopmental disability. We aimed to assess the safety and efficacy of a replication-defective investigational CMV vaccine, V160, in CMV-seronegative women.

METHODS

This phase 2b, randomised, double-blind, placebo-controlled study was conducted at 90 sites in seven countries (USA, Finland, Canada, Israel, Spain, Russia, and Australia). Eligible participants were generally healthy, CMV-seronegative, non-pregnant, 16-35-year-old women of childbearing potential with exposure to children aged 5 years or younger. Participants were randomly assigned using central randomisation via an interactive response technology system 1:1:1 to one of three groups: V160 three-dose regimen (V160 at day 1, month 2, and month 6), V160 two-dose regimen (V160 on day 1, placebo at month 2, and V160 at month 6), or placebo (saline solution at day 1, month 2, and month 6). The primary outcomes were the efficacy of three doses of V160 in reducing the incidence of primary CMV infection during the follow-up period starting 30 days after the last dose of vaccine using a fixed event rate design, and the safety and tolerability of the two-dose and three-dose V160 regimens. We planned to test the efficacy of a two-dose regimen of V160 in reducing the incidence of primary CMV infection only if the primary efficacy hypothesis was met. Analyses for the primary efficacy endpoint were performed on the per-protocol efficacy population; safety analyses included all randomly assigned participants who received study vaccine. The primary efficacy hypothesis was tested at prespecified interim and final analyses. The study was ongoing and efficacy data continued to accrue at the time of final testing of the primary efficacy hypothesis. Vaccine efficacy was re-estimated after final testing of the primary efficacy hypothesis based on all available efficacy data at end of study. This trial is registered at ClinicalTrials.gov (NCT03486834) and EudraCT (2017-004233-86) and is complete.

FINDINGS

Between April 30, 2018, and Aug 30, 2019, 7458 participants were screened, of whom 2220 were randomly assigned to the V160 three-dose group (n=733), V160 two-dose group (n=733), or placebo group (n=734). A total of 523 participants in the V160 three-dose group and 519 in the placebo group were included in the final hypothesis testing. Of these, there were 11 cases of CMV infection in the V160 three-dose group and 20 cases in the placebo group. The vaccine efficacy for the V160 three-dose group was 44·6% (95% CI -15·2 to 74·8) at the final testing of the primary efficacy hypothesis, a result corresponding to failure to demonstrate the primary efficacy hypothesis. On the basis of this result, the study was terminated for futility. The re-estimate of vaccine efficacy for the V160 three-dose group based on all available efficacy data at end of study (556 participants in the V160 three-dose group and 543 in the placebo group) was 42·4% (95% CI -13·5 to 71·1). A total of 728 participants in the V160 three-dose group, 729 in the V160 two-dose group, and 732 in the placebo group were included in the safety analyses. The most common solicited injection-site adverse event was injection-site pain (680 [93%] in the V160 three-dose group, 659 [90%] in the V160 two-dose group, and 232 [32%] in the placebo group). The most common solicited systemic adverse event was fatigue (457 [63%] in the V160 three-dose group, 461 [63%] in the V160 two-dose group, and 357 [49%] in the placebo group). No vaccine-related serious adverse events or deaths were reported.

INTERPRETATION

V160 was generally well tolerated and immunogenic; however, three doses of the vaccine did not reduce the incidence of primary CMV infection in CMV-seronegative women compared with placebo. This study provides insights into the design of future CMV vaccine efficacy trials, particularly for the identification of CMV infection using molecular assays.

FUNDING

Merck Sharp & Dohme, a subsidiary of Merck & Co, Rahway, NJ, USA (MSD).

A phase I randomized, double-blind, placebo-controlled study to evaluate the safety, tolerability, and immunogenicity of a live-attenuated quadrivalent dengue vaccine in flavivirus-naïve and flavivirus-experienced healthy adults

Dengue (DENV) is a mosquito-borne virus with four serotypes causing substantial morbidity in tropical and subtropical areas worldwide. V181 is an investigational, live, attenuated, quadrivalent dengue vaccine. In this phase 1 double-blind, placebo-controlled study, the safety, tolerability, and immunogenicity of V181 in baseline flavivirus-naïve (BFN) and flavivirus-experienced (BFE) healthy adults were evaluated in two formulations: TV003 and TV005. TV005 contains a 10-fold higher DENV2 level than TV003. Two-hundred adults were randomized 2:2:1 to receive TV003, TV005, or placebo on Days 1 and 180. Immunogenicity against the 4 DENV serotypes was measured using a Virus Reduction Neutralization Test (VRNT₆₀) after each vaccination and out to 1 year after the second dose. There were no discontinuations due to adverse events (AE) or serious vaccine-related AEs in the study. Most common AEs after TV003 or TV005 were headache, rash, fatigue, and myalgia. Tri- or tetravalent vaccine-viremia was detected in 63.9% and 25.6% of BFN TV003 and TV005 participants, respectively, post-dose 1 (PD1). Tri- or tetravalent dengue VRNT₆₀ seropositivity was demonstrated in 92.6% of BFN TV003, 74.2% of BFN TV005, and 100% of BFE TV003 and TV005 participants PD1. Increases in VRNT₆₀ GMTs were observed after the first vaccination with TV003 and TV005 in both flavivirus subgroups for all dengue serotypes, and minimal increases were measured PD2. GMTs in the TV003 and TV005 BFE and BFN groups remained above the respective baselines and placebo through 1-year PD2. These data support further development of V181 as a single-dose vaccine for the prevention of dengue disease.

Etiologies of Acute Undifferentiated Febrile Illnesses in and near Iquitos from 1993 to 1999 in the Amazon River Basin of Peru

The objective of this study was to determine the etiology of febrile illnesses among patients from October 1, 1993 through September 30, 1999, in the urban community of Iquitos in the Amazon River Basin of Peru. Epidemiological and clinical data as well as blood samples were obtained from consenting patients at hospitals, health clinics and private residences. Samples were tested for arboviruses in cell cultures and for IgM and IgG antibodies by ELISA. Blood smears were examined for malaria, and sera were tested for antibodies to Leptospira spp. by ELISA and microscopic agglutination. Among 6,607 febrile patients studied, dengue viruses caused 14.6% of the cases, and Venezuelan equine encephalitis virus caused 2.5%, Oropouche virus 1.0%, Mayaro virus 0.4%, and other arboviruses caused 0.2% of the cases. Also, 22.9% of 4,844 patients tested were positive for malaria, and of 400 samples tested, 9% had evidence of acute leptospirosis. Although the study was not designed to assess the importance of these pathogens as a cause of human morbidity in the total population, these results indicate that arboviruses, leptospirosis, and malaria were the cause of approximately 50% of the febrile cases. Although the arboviruses that were diagnosed can produce asymptomatic infections, our findings increased the overall understanding of the relative health burden of these infections, as well as baseline knowledge needed for designing and implementing further studies to better assess the health impact and threat of these pathogens in the Amazon Basin of Peru.

Cold-Chain Adaptability During Introduction of Inactivated Polio Vaccine in Bangladesh, 2015

Background.

Introduction of inactivated polio vaccine creates challenges in maintaining the cold chain for vaccine storage and distribution.

Methods.

We evaluated the cold chain in 23 health facilities and 36 outreach vaccination sessions in 8 districts and cities of Bangladesh, using purposive sampling during August–October 2015. We interviewed immunization and cold-chain staff, assessed equipment, and recorded temperatures during vaccine storage and transportation.

Results.

All health facilities had functioning refrigerators, and 96% had freezers. Temperature monitors were observed in all refrigerators and freezers but in only 14 of 66 vaccine transporters (21%). Recorders detected temperatures >8°C for >60 minutes in 5 of 23 refrigerators (22%), 3 of 6 cold boxes (50%) transporting vaccines from national to subnational depots, and 8 of 48 vaccine carriers (17%) used in outreach vaccination sites. Temperatures <2°C were detected in 4 of 19 cold boxes (21%) transporting vaccine from subnational depots to health facilities and 14 of 48 vaccine carriers (29%).

Conclusions.

Bangladesh has substantial cold-chain storage and transportation capacity after inactivated polio vaccine introduction, but temperature fluctuations during vaccine transport could cause vaccine potency loss that could go undetected. Bangladesh and other countries should strive to ensure consistent and sufficient cold-chain storage and monitor the cold chain during vaccine transportation at all levels.

Respiratory Infections in the U.S. Military: Recent Experience and Control

This comprehensive review outlines the impact of military-relevant respiratory infections, with special attention to recruit training environments, influenza pandemics in 1918 to 1919 and 2009 to 2010, and peacetime operations and conflicts in the past 25 years. Outbreaks and epidemiologic investigations of viral and bacterial infections among high-risk groups are presented, including (i) experience by recruits at training centers, (ii) impact on advanced trainees in special settings, (iii) morbidity sustained by shipboard personnel at sea, and (iv) experience of deployed personnel. Utilizing a pathogen-by-pathogen approach, we examine (i) epidemiology, (ii) impact in terms of morbidity and operational readiness, (iii) clinical presentation and outbreak potential, (iv) diagnostic modalities, (v) treatment approaches, and (vi) vaccine and other control measures. We also outline military-specific initiatives in (i) surveillance, (ii) vaccine development and policy, (iii) novel influenza and coronavirus diagnostic test development and surveillance methods, (iv) influenza virus transmission and severity prediction modeling efforts, and (v) evaluation and implementation of nonvaccine, nonpharmacologic interventions.

Molecular Epidemiology of Adenovirus Type 21 Respiratory Strains Isolated From US Military Trainees (1996-2014)

BACKGROUND

The circulation of human adenovirus type 21 (HAdV21) in the United States has been documented since the 1960s in association with outbreaks of febrile respiratory illness (FRI) in military boot camps and civilian cases of respiratory disease.

METHODS

To describe the molecular epidemiology of HAdV21 respiratory infections across the country, 150 clinical respiratory isolates obtained from continuous surveillance of military recruit FRI, and 23 respiratory isolates recovered from pediatric and adult civilian cases of acute respiratory infection were characterized to compile molecular typing data spanning 37 years (1978-2014).

RESULTS

Restriction enzyme analysis and genomic sequencing identified 2 clusters of closely related genomic variants readily distinguishable from the prototype and designated 21a-like and 21b-like. A-like variants predominated until 1999. A shift to b-like variants was noticeable by 2007 after a 7-year period (2000-2006) of cocirculation of the 2 genome types. US strains are phylogenetically more closely related to European and Asian strains isolated over the last 4 decades than to the Saudi Arabian prototype strain AV-1645 isolated in 1956.

CONCLUSIONS

Knowledge of circulating HAdV21 variants and their epidemic behavior will be of significant value to local and global FRI surveillance efforts.

Lack of effectiveness of the 23-valent polysaccharide pneumococcal vaccine in reducing all-cause pneumonias among healthy young military recruits: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Streptococcus pneumoniae infections have periodically caused significant morbidity and outbreaks among military personnel, especially trainees. This study evaluated the effectiveness of the 23-valent polysaccharide pneumococcal vaccine (PPV23) in reducing pneumonia in healthy military trainees.

METHODS

From 2000-2003, 152723 military trainees from 5 US training camps were enrolled in a double-blind, placebo-controlled trial of PPV23. Participants were closely monitored during basic training for radiographically confirmed pneumonia etiology and loss-of-training days. Participants were also followed using electronic medical encounter data until 1 June 2007 for three additional outcomes: any-cause pneumonia, any acute respiratory disease, and meningitis.

RESULTS

Comparison of demographic data by study arm suggested the randomization procedures were sound. During basic training, 371 study participants developed radiographically confirmed pneumonia. None had evidence of S. pneumoniae infection, but other etiologies included adenovirus (38%), Chlamydophila pneumoniae (9%), and Mycoplasma pneumoniae (8%). During the follow-up period, many study participants, in both the vaccine and placebo groups, had clinical encounters for the medical outcomes of interest. However, Cox's proportional hazard modeling revealed no evidence of a protective vaccine effect during recruit training (radiographically confirmed pneumonia) or up to 6.7 years after enrollment (any-cause pneumonia, any acute respiratory disease, or meningitis).

CONCLUSIONS

Data from this large, double-blind, placebo controlled trial do not support routine use of PPV23 among healthy new military trainees. This clinical trial was registered at clinicaltrials.gov (registration number NCT02079701, http://www.clinicaltrials.gov/ct2/show/NCT02079701?term=NCT02079701&rank=1).

A review of evaluations of electronic event-based biosurveillance systems

Electronic event-based biosurveillance systems (EEBS’s) that use near real-time information from the internet are an increasingly important source of epidemiologic intelligence. However, there has not been a systematic assessment of EEBS evaluations, which could identify key uncertainties about current systems and guide EEBS development to most effectively exploit web-based information for biosurveillance. To conduct this assessment, we searched PubMed and Google Scholar to identify peer-reviewed evaluations of EEBS’s. We included EEBS’s that use publicly available internet information sources, cover events that are relevant to human health, and have global scope. To assess the publications using a common framework, we constructed a list of 17 EEBS attributes from published guidelines for evaluating health surveillance systems. We identified 11 EEBS’s and 20 evaluations of these EEBS’s. The number of published evaluations per EEBS ranged from 1 (Gen-Db, GODsN, MiTAP) to 8 (GPHIN, HealthMap). The median number of evaluation variables assessed per EEBS was 8 (range, 3–15). Ten published evaluations contained quantitative assessments of at least one key variable. No evaluations examined usefulness by identifying specific public health decisions, actions, or outcomes resulting from EEBS outputs. Future EEBS assessments should identify and discuss critical indicators of public health utility, especially the impact of EEBS’s on public health response.

Dramatic decline of respiratory illness among US military recruits after the renewed use of adenovirus vaccines

BACKGROUND

In late 2011, after a 12-year hiatus, oral vaccines against adenovirus types 4 (Ad4) and 7 (Ad7) were again produced and administered to US military recruits. This study examined the impact of the new adenovirus vaccines on febrile respiratory illness (FRI) and adenovirus rates and investigated if new serotypes emerged. FRI rates and their associated hospitalizations had markedly risen since vaccine production ceased in 1999.

METHODS

From 1996 to 2013, the Naval Health Research Center conducted FRI surveillance at 8 military recruit training centers in the United States. During this period, 58 103 FRI pharyngeal swab specimens were studied, yielding 37 048 adenovirus-positive cases, among which 64% were typed.

RESULTS

During the 2 years after reintroduction of the vaccines, military trainees experienced a 100-fold decline in adenovirus disease burden (from 5.8 to 0.02 cases per 1000 person-weeks, P < .0001), without evidence that vaccine pressure had increased the impact of adenovirus types other than Ad4 and Ad7. Although the percentage of type 14 increased following reintroduction of the vaccination, the actual number of cases decreased. We estimate that the vaccines prevent approximately 1 death, 1100-2700 hospitalizations, and 13 000 febrile adenovirus cases each year among the trainees.

CONCLUSIONS

These data strongly support the continued production and use of Ad4 and Ad7 vaccines in controlling FRI among US military trainees. Continued surveillance for emerging adenovirus subtypes is warranted.

Fish oil improves motor function, limits blood-brain barrier disruption, and reduces Mmp9 gene expression in a rat model of juvenile traumatic brain injury

The effects of an oral fish oil treatment regimen on sensorimotor, blood-brain barrier, and biochemical outcomes of traumatic brain injury (TBI) were investigated in a juvenile rat model. Seventeen-day old Long-Evans rats were given a 15mL/kg fish oil (2.01g/kg EPA, 1.34g/kg DHA) or soybean oil dose via oral gavage 30min prior to being subjected to a controlled cortical impact injury or sham surgery, followed by daily doses for seven days. Fish oil treatment resulted in less severe hindlimb deficits after TBI as assessed with the beam walk test, decreased cerebral IgG infiltration, and decreased TBI-induced expression of the Mmp9 gene one day after injury. These results indicate that fish oil improved functional outcome after TBI resulting, at least in part from decreased disruption of the blood-brain barrier through a mechanism that includes attenuation of TBI-induced expression of Mmp9.

Notes from the field: Department of Defense response to a multistate outbreak of fungal meningitis--United States, October 2012

On October 1, 2012, the Department of Defense (DoD) learned of a multistate outbreak of fungal meningitis in persons who received injections of methylprednisolone acetate (MPA) from a single compounding pharmacy. Ten patients with fungal meningitis after epidural steroid injection (ESI) were initially identified in Tennessee and North Carolina. No military treatment facilities had received MPA from this pharmacy. However, clinics receiving implicated MPA lots were located throughout the United States, and active duty military service members and other DoD health-care beneficiaries could have been exposed through health-care services purchased outside of the DoD health-care system. Therefore, a timely method was needed to determine whether exposure to implicated MPA had occurred among DoD personnel who used purchased care.

Contributions of the Global Emerging Infections Surveillance and Response System Network to global health security in 2011

In its 15th year, the Global Emerging Infections Surveillance and Response System (GEIS) continued to make significant contributions to global public health and emerging infectious disease surveillance worldwide. As a division of the US Department of Defense's Armed Forces Health Surveillance Center since 2008, GEIS coordinated a network of surveillance and response activities through collaborations with 33 partners in 76 countries. The GEIS was involved in 73 outbreak responses in fiscal year 2011. Significant laboratory capacity-building initiatives were undertaken with 53 foreign health, agriculture and/or defense ministries, as well as with other US government entities and international institutions, including support for numerous national influenza centers. Equally important, a variety of epidemiologic training endeavors reached over 4,500 individuals in 96 countries. Collectively, these activities enhanced the ability of partner countries and the US military to make decisions about biological threats and design programs to protect global public health as well as global health security.

Effectiveness of seasonal influenza vaccines against influenza-associated illnesses among US military personnel in 2010-11: a case-control approach

INTRODUCTION

Following the 2009 influenza A/H1N1 (pH1N1) pandemic, both seasonal and pH1N1 viruses circulated in the US during the 2010-2011 influenza season; influenza vaccine effectiveness (VE) may vary between live attenuated (LAIV) and trivalent inactivated (TIV) vaccines as well as by virus subtype.

MATERIALS AND METHODS

Vaccine type and virus subtype-specific VE were determined for US military active component personnel for the period of September 1, 2010 through April 30, 2011. Laboratory-confirmed influenza-related medical encounters were compared to matched individuals with a non-respiratory illness (healthy controls), and unmatched individuals who experienced a non-influenza respiratory illness (test-negative controls). Odds ratios (OR) and VE estimates were calculated overall, by vaccine type and influenza subtype.

RESULTS

A total of 603 influenza cases were identified. Overall VE was relatively low and similar regardless of whether healthy controls (VE = 26%, 95% CI: -1 to 45) or test-negative controls (VE = 29%, 95% CI: -6 to 53) were used as comparison groups. Using test-negative controls, vaccine type-specific VE was found to be higher for TIV (53%, 95% CI: 25 to 71) than for LAIV (VE = -13%, 95% CI: -77 to 27). Influenza subtype-specific analyses revealed moderate protection against A/H3 (VE = 58%, 95% CI: 21 to 78), but not against A/H1 (VE = -38%, 95% CI: -211 to 39) or B (VE = 34%, 95% CI: -122 to 80).

CONCLUSION

Overall, a low level of protection against clinically-apparent, laboratory-confirmed, influenza was found for the 2010-11 seasonal influenza vaccines. TIV immunization was associated with higher protection than LAIV, however, no protection against A/H1 was noted, despite inclusion of a pandemic influenza strain as a vaccine component for two consecutive years. Vaccine virus mismatch or lower immunogenicity may have contributed to these findings and deserve further examination in controlled studies. Continued assessment of VE in military personnel is essential in order to better inform vaccination policy decisions.

Spatial dimensions of dengue virus transmission across interepidemic and epidemic periods in Iquitos, Peru (1999-2003)

Background

Knowledge of spatial patterns of dengue virus (DENV) infection is important for understanding transmission dynamics and guiding effective disease prevention strategies. Because movement of infected humans and mosquito vectors plays a role in the spread and persistence of virus, spatial dimensions of transmission can range from small household foci to large community clusters. Current understanding is limited because past analyses emphasized clinically apparent illness and did not account for the potentially large proportion of inapparent infections. In this study we analyzed both clinically apparent and overall infections to determine the extent of clustering among human DENV infections.

Methodology/Principal Findings

We conducted spatial analyses at global and local scales, using acute case and seroconversion data from a prospective longitudinal cohort in Iquitos, Peru, from 1999–2003. Our study began during a period of interepidemic DENV-1 and DENV-2 transmission and transitioned to epidemic DENV-3 transmission. Infection status was determined by seroconversion based on plaque neutralization testing of sequential blood samples taken at approximately six-month intervals, with date of infection assigned as the middate between paired samples. Each year was divided into three distinct seasonal periods of DENV transmission. Spatial heterogeneity was detected in baseline seroprevalence for DENV-1 and DENV-2. Cumulative DENV-3 seroprevalence calculated by trimester from 2001–2003 was spatially similar to preexisting DENV-1 and DENV-2 seroprevalence. Global clustering (case-control Ripley's K statistic) appeared at radii of ∼200–800 m. Local analyses (Kuldorf spatial scan statistic) identified eight DENV-1 and 15 DENV-3 clusters from 1999–2003. The number of seroconversions per cluster ranged from 3–34 with radii from zero (a single household) to 750 m; 65% of clusters had radii >100 m. No clustering was detected among clinically apparent infections.

Conclusions/Significance

Seroprevalence of previously circulating DENV serotypes can be a predictor of transmission risk for a different invading serotype and, thus, identify targets for strategically placed surveillance and intervention. Seroprevalence of a specific serotype is also important, but does not preclude other contributing factors, such as mosquito density, in determining where transmission of that virus will occur. Regardless of the epidemiological context or virus serotype, human movement appears to be an important factor in defining the spatial dimensions of DENV transmission and, thus, should be considered in the design and evaluation of surveillance and intervention strategies.

To target prevention and control strategies for dengue fever, it is essential to understand how the virus travels through the city. We report spatial analyses of dengue infections from a study monitoring school children and adult family members for dengue infection at six-month intervals from 1999–2003, in the Amazonian city of Iquitos, Peru. At the beginning of the study, only DENV serotypes 1 and 2 were circulating. Clusters of infections of these two viruses were concentrated in the northern region of the city, where mosquito indices and previous DENV infection were both high. In 2002, DENV-3 invaded the city, replacing DENV-1 and -2 as the dominant strain. During the invasion process, the virus spread rapidly across the city, at low levels. After this initial phase, clusters of infection appeared first in the northern region of the city, where clusters of DENV-1 and DENV-2 had occurred in prior years. Most of the clusters we identified had radii >100 meters, indicating that targeted or reactive treatment of these high-risk areas might be an effective proactive intervention strategy. Our results also help explain why vector control within 100 m of a dengue case is often not successful for large-scale disease prevention.

Climate teleconnections and recent patterns of human and animal disease outbreaks

Background

Recent clusters of outbreaks of mosquito-borne diseases (Rift Valley fever and chikungunya) in Africa and parts of the Indian Ocean islands illustrate how interannual climate variability influences the changing risk patterns of disease outbreaks. Although Rift Valley fever outbreaks have been known to follow periods of above-normal rainfall, the timing of the outbreak events has largely been unknown. Similarly, there is inadequate knowledge on climate drivers of chikungunya outbreaks. We analyze a variety of climate and satellite-derived vegetation measurements to explain the coupling between patterns of climate variability and disease outbreaks of Rift Valley fever and chikungunya.

Methods and Findings

We derived a teleconnections map by correlating long-term monthly global precipitation data with the NINO3.4 sea surface temperature (SST) anomaly index. This map identifies regional hot-spots where rainfall variability may have an influence on the ecology of vector borne disease. Among the regions are Eastern and Southern Africa where outbreaks of chikungunya and Rift Valley fever occurred 2004–2009. Chikungunya and Rift Valley fever case locations were mapped to corresponding climate data anomalies to understand associations between specific anomaly patterns in ecological and climate variables and disease outbreak patterns through space and time. From these maps we explored associations among Rift Valley fever disease occurrence locations and cumulative rainfall and vegetation index anomalies. We illustrated the time lag between the driving climate conditions and the timing of the first case of Rift Valley fever. Results showed that reported outbreaks of Rift Valley fever occurred after ∼3–4 months of sustained above-normal rainfall and associated green-up in vegetation, conditions ideal for Rift Valley fever mosquito vectors. For chikungunya we explored associations among surface air temperature, precipitation anomalies, and chikungunya outbreak locations. We found that chikungunya outbreaks occurred under conditions of anomalously high temperatures and drought over Eastern Africa. However, in Southeast Asia, chikungunya outbreaks were negatively correlated (p<0.05) with drought conditions, but positively correlated with warmer-than-normal temperatures and rainfall.

Conclusions/Significance

Extremes in climate conditions forced by the El Niño/Southern Oscillation (ENSO) lead to severe droughts or floods, ideal ecological conditions for disease vectors to emerge, and may result in epizootics and epidemics of Rift Valley fever and chikungunya. However, the immune status of livestock (Rift Valley fever) and human (chikungunya) populations is a factor that is largely unknown but very likely plays a role in the spatial-temporal patterns of these disease outbreaks. As the frequency and severity of extremes in climate increase, the potential for globalization of vectors and disease is likely to accelerate. Understanding the underlying patterns of global and regional climate variability and their impacts on ecological drivers of vector-borne diseases is critical in long-range planning of appropriate disease and disease-vector response, control, and mitigation strategies.

Interannual climate variability associated with the El Niño/Southern Oscillation (ENSO) phenomenon and regional climatic circulation mechanisms in the equatorial Indian Ocean result in significant rainfall and ecological anomaly patterns that are major drivers of spatial and temporal patterns of mosquito-borne disease outbreaks. Correlation and regression analyses of long time series rainfall, vegetation index, and temperature data show that large scale anomalies occur periodically that may influence mosquito vector populations and thus spatial and temporal patterns of Rift Valley fever and chikungunya outbreaks. Rift Valley fever outbreak events occurred after a period of ∼3–4 months of persistent and above-normal rainfall that enabled vector habitats to flourish. On the other hand, chikungunya outbreaks occurred during periods of high temperatures and severe drought over East Africa and the western Indian Ocean islands. This is consistent with highly populated environmental settings where domestic and peri-domestic stored water containers were the likely mosquito sources. However, in Southeast Asia, approximately 52% of chikungunya outbreaks occurred during cooler-than-normal temperatures and were significantly negatively correlated with drought. Besides climate variability, other factors not accounted for such as vertebrate host immunity may contribute to spatio-temporal patterns of outbreaks.

Influenza-like illness surveillance on the California-Mexico border, 2004-2009

BACKGROUND

Since 2004, the Naval Health Research Center, with San Diego and Imperial counties, has collaborated with the US Centers for Disease Control and Prevention to conduct respiratory disease surveillance in the US-Mexico border region. In 2007, the Secretariat of Health, Mexico and the Institute of Public Health of Baja California joined the collaboration.

OBJECTIVES

The identification of circulating respiratory pathogens in respiratory specimens from patients with influenza-like illness (ILI).

METHODS

Demographic, symptom information and respiratory swabs were collected from enrollees who met the case definition for ILI. Specimens underwent PCR testing and culture in virology and bacteriology.

RESULTS

From 2004 through 2009, 1855 persons were sampled. Overall, 36% of the participants had a pathogen identified. The most frequent pathogen was influenza (25%), with those aged 6-15 years the most frequently affected. In April 2009, a young female participant from Imperial County, California, was among the first documented cases of 2009 H1N1. Additional pathogens included influenza B, adenovirus, parainfluenza virus, respiratory syncytial virus, enterovirus, herpes simplex virus, Streptococcus pneumoniae, and Streptococcus pyogenes.

CONCLUSIONS

The US-Mexico border is one of the busiest in the world, with a large number of daily crossings. Due to its traffic, this area is an ideal location for surveillance sites. We identified a pathogen in 36% of the specimens tested, with influenza A the most common pathogen. A number of other viral and bacterial respiratory pathogens were identified. An understanding of the incidence of respiratory pathogens in border populations is useful for development of regional vaccination and disease prevention responses.

Serum penicillin G levels are lower than expected in adults within two weeks of administration of 1.2 million units

When introduced in the 1950s, benzathine penicillin G (BPG) was shown to be effective in eradicating group A beta-hemolytic streptococcus (GAS) for at least 3 weeks after administration. Several studies since the 1990s suggest that at 3-4 weeks serum penicillin G levels are less than adequate (below MIC(90) of 0.016 µg/ml). We studied these levels for 4 weeks after the recommended dose of BPG in military recruits, for whom it is used as prophylaxis against GAS. The 329 subjects (mean age 20 years) each received 1.2 million units BPG IM and gave sera 1 day post injection and twice more at staggered time points over 4 weeks. Serum penicillin G levels were measured by liquid chromatography/tandem mass spectometry. The half-life of serum penicillin G was 4.1 days. By day 11, mean levels were <0.02 µg/ml, and by day 15<0.01 µg/ml. Levels in more than 50% of the subjects were below 0.02 µg/ml on day 9, and <.01 µg/ml on day 16. There was no demonstrable effect of subject body-surface area nor of the four different lots of BPG used. These data indicate that in healthy young adults serum penicillin G levels become less than protective <2½ weeks after injection of 1.2 million units of BPG. The findings require serious consideration in future medical and public health recommendations for treatment and prophylaxis of GAS upper respiratory tract infections.

Local changes in rates of group A Streptococcus disease and antibiotic resistance are associated with geographically widespread strain turnover events

This study addresses the effects of dynamic strain turnover and antibiotic prophylaxis on rates of group A Streptococcus (GAS) antibiotic resistance and disease. The authors analyzed the strain distributions, disease rates, and patterns of antibiotic resistance of 802 GAS isolates collected from 2002 through 2007. These samples were collected from patients with GAS infection symptoms at 10 military facilities. Macrolide resistance peaked at 25% during 2004, due to the geographically widespread dominance of a single resistant strain (M75). The resistant strain was not retained regardless of local patterns of macrolide use, and resistance rates decreased upon replacement of M75 with macrolide-susceptible strains. Disease rates were similarly correlated with dominance of specific M types. Statistical analysis revealed temporal correlations between strain distributions at multiple locations. Only the most common strains yielded enough data at multiple sites for statistically significant comparison of temporal fluctuations in dominance, but these (including M44, M3, M18, M118, and M6) all yielded highly significant temporal correlations of 90% or greater on yearly scales. As expected given the complexity and variability of strain distributions on shorter time scales, analysis on a monthly scale yielded lower degrees of positive correlation (31-62%), but in this case all significant correlations were still positive. Shifts in antibiotic resistance profiles and disease rates at specific sites appear to be associated with strain replacements happening on larger scales, independent of antibiotic use at individual sites.

Capacity-building efforts by the AFHSC-GEIS program

Capacity-building initiatives related to public health are defined as developing laboratory infrastructure, strengthening host-country disease surveillance initiatives, transferring technical expertise and training personnel. These initiatives represented a major piece of the Armed Forces Health Surveillance Center, Division of Global Emerging Infections Surveillance and Response System (AFHSC-GEIS) contributions to worldwide emerging infectious disease (EID) surveillance and response. Capacity-building initiatives were undertaken with over 80 local and regional Ministries of Health, Agriculture and Defense, as well as other government entities and institutions worldwide. The efforts supported at least 52 national influenza centers and other country-specific influenza, regional and U.S.-based EID reference laboratories (44 civilian, eight military) in 46 countries worldwide. Equally important, reference testing, laboratory infrastructure and equipment support was provided to over 500 field sites in 74 countries worldwide from October 2008 to September 2009. These activities allowed countries to better meet the milestones of implementation of the 2005 International Health Regulations and complemented many initiatives undertaken by other U.S. government agencies, such as the U.S. Department of Health and Human Services, the U.S. Agency for International Development and the U.S. Department of State.

Department of Defense influenza and other respiratory disease surveillance during the 2009 pandemic

The Armed Forces Health Surveillance Center's Division of Global Emerging Infections Surveillance and Response System (AFHSC-GEIS) supports and oversees surveillance for emerging infectious diseases, including respiratory diseases, of importance to the U.S. Department of Defense (DoD). AFHSC-GEIS accomplishes this mission by providing funding and oversight to a global network of partners for respiratory disease surveillance. This report details the system's surveillance activities during 2009, with a focus on efforts in responding to the novel H1N1 Influenza A (A/H1N1) pandemic and contributions to global public health. Active surveillance networks established by AFHSC-GEIS partners resulted in the initial detection of novel A/H1N1 influenza in the U.S. and several other countries, and viruses isolated from these activities were used as seed strains for the 2009 pandemic influenza vaccine. Partners also provided diagnostic laboratory training and capacity building to host nations to assist with the novel A/H1N1 pandemic global response, adapted a Food and Drug Administration-approved assay for use on a ruggedized polymerase chain reaction platform for diagnosing novel A/H1N1 in remote settings, and provided estimates of seasonal vaccine effectiveness against novel A/H1N1 illness. Regular reporting of the system's worldwide surveillance findings to the global public health community enabled leaders to make informed decisions on disease mitigation measures and controls for the 2009 A/H1N1 influenza pandemic. AFHSC-GEIS's support of a global network contributes to DoD's force health protection, while supporting global public health.

Malaria and other vector-borne infection surveillance in the U.S. Department of Defense Armed Forces Health Surveillance Center-Global Emerging Infections Surveillance program: review of 2009 accomplishments

Vector-borne infections (VBI) are defined as infectious diseases transmitted by the bite or mechanical transfer of arthropod vectors. They constitute a significant proportion of the global infectious disease burden. United States (U.S.) Department of Defense (DoD) personnel are especially vulnerable to VBIs due to occupational contact with arthropod vectors, immunological naiveté to previously unencountered pathogens, and limited diagnostic and treatment options available in the austere and unstable environments sometimes associated with military operations. In addition to the risk uniquely encountered by military populations, other factors have driven the worldwide emergence of VBIs. Unprecedented levels of global travel, tourism and trade, and blurred lines of demarcation between zoonotic VBI reservoirs and human populations increase vector exposure. Urban growth in previously undeveloped regions and perturbations in global weather patterns also contribute to the rise of VBIs. The Armed Forces Health Surveillance Center-Global Emerging Infections Surveillance and Response System (AFHSC-GEIS) and its partners at DoD overseas laboratories form a network to better characterize the nature, emergence and growth of VBIs globally. In 2009 the network tested 19,730 specimens from 25 sites for Plasmodium species and malaria drug resistance phenotypes and nearly another 10,000 samples to determine the etiologies of non-Plasmodium species VBIs from regions spanning from Oceania to Africa, South America, and northeast, south and Southeast Asia. This review describes recent VBI-related epidemiological studies conducted by AFHSC-GEIS partner laboratories within the OCONUS DoD laboratory network emphasizing their impact on human populations.

The AFHSC-Division of GEIS Operations Predictive Surveillance Program: a multidisciplinary approach for the early detection and response to disease outbreaks

The Armed Forces Health Surveillance Center, Division of Global Emerging Infections Surveillance and Response System Operations (AFHSC-GEIS) initiated a coordinated, multidisciplinary program to link data sets and information derived from eco-climatic remote sensing activities, ecologic niche modeling, arthropod vector, animal disease-host/reservoir, and human disease surveillance for febrile illnesses, into a predictive surveillance program that generates advisories and alerts on emerging infectious disease outbreaks. The program’s ultimate goal is pro-active public health practice through pre-event preparedness, prevention and control, and response decision-making and prioritization. This multidisciplinary program is rooted in over 10 years experience in predictive surveillance for Rift Valley fever outbreaks in Eastern Africa. The AFHSC-GEIS Rift Valley fever project is based on the identification and use of disease-emergence critical detection points as reliable signals for increased outbreak risk. The AFHSC-GEIS predictive surveillance program has formalized the Rift Valley fever project into a structured template for extending predictive surveillance capability to other Department of Defense (DoD)-priority vector- and water-borne, and zoonotic diseases and geographic areas. These include leishmaniasis, malaria, and Crimea-Congo and other viral hemorrhagic fevers in Central Asia and Africa, dengue fever in Asia and the Americas, Japanese encephalitis (JE) and chikungunya fever in Asia, and rickettsial and other tick-borne infections in the U.S., Africa and Asia.

U.S. Government engagement in support of global disease surveillance

Global cooperation is essential for coordinated planning and response to public health emergencies, as well as for building sufficient capacity around the world to detect, assess and respond to health events. The United States is committed to, and actively engaged in, supporting disease surveillance capacity building around the world. We recognize that there are many agencies involved in this effort, which can become confusing to partner countries and other public health entities. This paper aims to describe the agencies and offices working directly on global disease surveillance capacity building in order to clarify the United States Government interagency efforts in this space.

Arboviral etiologies of acute febrile illnesses in Western South America, 2000-2007

BACKGROUND

Arthropod-borne viruses (arboviruses) are among the most common agents of human febrile illness worldwide and the most important emerging pathogens, causing multiple notable epidemics of human disease over recent decades. Despite the public health relevance, little is know about the geographic distribution, relative impact, and risk factors for arbovirus infection in many regions of the world. Our objectives were to describe the arboviruses associated with acute undifferentiated febrile illness in participating clinics in four countries in South America and to provide detailed epidemiological analysis of arbovirus infection in Iquitos, Peru, where more extensive monitoring was conducted.

METHODOLOGY/FINDINGS

A clinic-based syndromic surveillance system was implemented in 13 locations in Ecuador, Peru, Bolivia, and Paraguay. Serum samples and demographic information were collected from febrile participants reporting to local health clinics or hospitals. Acute-phase sera were tested for viral infection by immunofluorescence assay or RT-PCR, while acute- and convalescent-phase sera were tested for pathogen-specific IgM by ELISA. Between May 2000 and December 2007, 20,880 participants were included in the study, with evidence for recent arbovirus infection detected for 6,793 (32.5%). Dengue viruses (Flavivirus) were the most common arbovirus infections, totaling 26.0% of febrile episodes, with DENV-3 as the most common serotype. Alphavirus (Venezuelan equine encephalitis virus [VEEV] and Mayaro virus [MAYV]) and Orthobunyavirus (Oropouche virus [OROV], Group C viruses, and Guaroa virus) infections were both observed in approximately 3% of febrile episodes. In Iquitos, risk factors for VEEV and MAYV infection included being male and reporting to a rural (vs urban) clinic. In contrast, OROV infection was similar between sexes and type of clinic.

CONCLUSIONS/SIGNIFICANCE

Our data provide a better understanding of the geographic range of arboviruses in South America and highlight the diversity of pathogens in circulation. These arboviruses are currently significant causes of human illness in endemic regions but also have potential for further expansion. Our data provide a basis for analyzing changes in their ecology and epidemiology.

Influenza and respiratory disease surveillance: the US military's global laboratory-based network

Please cite this paper as: Jeremy Sueker et al. (2010) Influenza and respiratory disease surveillance: the US military’s global laboratory‐based network. Influenza and Other Respiratory Viruses 4(3), 155–161.

The US Department of Defense influenza surveillance system now spans nearly 500 sites in 75 countries, including active duty US military and dependent populations as well as host‐country civilian and military personnel. This system represents a major part of the US Government’s contributions to the World Health Organization’s Global Influenza Surveillance Network and addresses Presidential Directive NSTC‐7 to expand global surveillance, training, research and response to emerging infectious disease threats. Since 2006, the system has expanded significantly in response to rising pandemic influenza concerns. The expanded system has played a critical role in the detection and monitoring of ongoing H5N1 outbreaks worldwide as well as in the initial detection of, and response to, the current (H1N1) 2009 influenza pandemic. This article describes the system, details its contributions and the critical gaps that it is filling, and discusses future plans.

Seasonal influenza vaccine and protection against pandemic (H1N1) 2009-associated illness among US military personnel

Introduction

A novel A/H1N1 virus is the cause of the present influenza pandemic; vaccination is a key countermeasure, however, few data assessing prior seasonal vaccine effectiveness (VE) against the pandemic strain of H1N1 (pH1N1) virus are available.

Materials and Methods

Surveillance of influenza-related medical encounter data of active duty military service members stationed in the United States during the period of April–October 2009 with comparison of pH1N1-confirmed cases and location and date-matched controls. Crude odds ratios (OR) and VE estimates for immunized versus non-immunized were calculated as well as adjusted OR (AOR) controlling for sex, age group, and history of prior influenza vaccination. Separate stratified VE analyses by vaccine type (trivalent inactivated [TIV] or live attenuated [LAIV]), age groups and hospitalization status were also performed. For the period of April 20 to October 15, 2009, a total of 1,205 cases of pH1N1-confirmed cases were reported, 966 (80%) among males and over one-half (58%) under 25 years of age. Overall VE for service members was found to be 45% (95% CI, 33 to 55%). Immunization with prior season's TIV (VE = 44%, 95% CI, 32 to 54%) as well as LAIV (VE = 24%, 95% CI, 6 to 38%) were both found to be associated with protection. Of significance, VE against a severe disease outcome was higher (VE = 62%, 95% CI, 14 to 84%) than against milder outcomes (VE = 42%, 95% CI, 29 to 53%).

Conclusion

A moderate association with protection against clinically apparent, laboratory-confirmed Pandemic (H1N1) 2009-associated illness was found for immunization with either TIV or LAIV 2008–09 seasonal influenza vaccines. This association with protection was found to be especially apparent for severe disease as compared to milder outcome, as well as in the youngest and older populations. Prior vaccination with seasonal influenza vaccines in 2004–08 was also independently associated with protection.

Epidemiology of dengue virus in Iquitos, Peru 1999 to 2005: interepidemic and epidemic patterns of transmission

Background

Comprehensive, longitudinal field studies that monitor both disease and vector populations for dengue viruses are urgently needed as a pre-requisite for developing locally adaptable prevention programs or to appropriately test and license new vaccines.

Methodology and Principal Findings

We report the results from such a study spanning 5 years in the Amazonian city of Iquitos, Peru where DENV infection was monitored serologically among ∼2,400 members of a neighborhood-based cohort and through school-based absenteeism surveillance for active febrile illness among a subset of this cohort. At baseline, 80% of the study population had DENV antibodies, seroprevalence increased with age, and significant geographic variation was observed, with neighborhood-specific age-adjusted rates ranging from 67.1 to 89.9%. During the first 15 months, when DENV-1 and DENV-2 were co-circulating, population-based incidence rates ranged from 2–3 infections/100 person-years (p-years). The introduction of DENV-3 during the last half of 2001 was characterized by 3 distinct periods: amplification over at least 5–6 months, replacement of previously circulating serotypes, and epidemic transmission when incidence peaked at 89 infections/100 p-years.

Conclusions/Significance

Neighborhood-specific baseline seroprevalence rates were not predictive of geographic incidence patterns prior to the DENV-3 introduction, but were closely mirrored during the invasion of this serotype. Transmission varied geographically, with peak incidence occurring at different times among the 8 geographic zones in ∼16 km² of the city. The lag from novel serotype introduction to epidemic transmission and knowledge of spatially explicit areas of elevated risk should be considered for more effective application of limited resources for dengue prevention.

To develop prevention (including vaccines) and control programs for dengue fever, a significant mosquito-borne disease in the tropics, there is an urgent need for comprehensive long term field epidemiological studies. We report results from a study that monitored ∼2,400 school children and some adult family members for dengue infection at 6 month intervals from 1999 to 2005, in the Amazonian city of Iquitos, Peru. At enrollment, ∼80% of the participants had a previous infection with DENV serotypes 1 and 2 or both. During the first 15 months, about 3 new infections for every 100 participants were observed among the study participants. In 2001, DENV-3, a serotype not previously observed in the region, invaded Iquitos in a process characterized by 3 distinct periods: amplification over at least a 5–6 month period, replacement of previously circulating serotypes, and epidemic transmission when incidence peaked. Incidence patterns of new infections were geographically distinct from baseline prevalence rates prior to arrival of DENV-3, but closely mirrored them during the invasion. DENV transmission varied geographically corresponding to elevated mosquito densities. The invasion of a novel serotype is often characterized by 5–6 months of silent transmission before traditional surveillance programs detect the virus. This article sets the stage for subsequent publications on dengue epidemiology.

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

Military recruits experience a high incidence of febrile respiratory illness (FRI), leading to significant morbidity and lost training time. Adenoviruses, group A Streptococcus pyogenes, and influenza virus are implicated in over half of the FRI cases reported at recruit training center clinics, while the etiology of the remaining cases is unclear. In this study, we explore the carriage rates and disease associations of adenovirus, enterovirus, rhinovirus, Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis in military recruits using high-density resequencing microarrays. The results showed that rhinoviruses, adenoviruses, S. pneumoniae, H. influenzae, and N. meningitidis were widely distributed in recruits. Of these five agents, only adenovirus showed significant correlation with illness. Among the samples tested, only pathogens associated with FRI, such as adenovirus 4 and enterovirus 68, revealed strong temporal and spatial clustering of specific strains, indicating that they are transmitted primarily within sites. The results showed a strong negative association between adenoviral FRI and the presence of rhinoviruses in recruits, suggesting some form of viral interference.

Global Infectious Disease Surveillance at DoD Overseas Laboratories, 1999-2007

The United States Department of Defense Global Emerging Infections Surveillance and Response System (DoD-GEIS) conducted a review in 2008 of projects funded by DoD-GEIS at five partner overseas laboratories from 1999 through 2007. During this period, the annual overseas programming budget grew from US$1.038 million to US$21 million. The review describes the distribution of project priorities and geographic locations over the years, the types of outcomes the projects generated, and the frequency with which they involved collaboration with other public health agencies and organizations, including CDC and WHO. Areas for further program strengthening are identified.

Viral agents responsible for febrile respiratory illnesses among military recruits training in tropical Singapore

Background

Military personnel are highly susceptible to febrile respiratory illnesses (FRI), likely due to crowding, stress and other risk factors present in the military environment.

Objective

Our objective was to investigate the viral etiological agents responsible for FRI among military recruits training in a tropical climate in Singapore.

Study design

From March 2006 through April 2007, a total of 1354 oropharyngeal (throat) swabs were collected from military recruits who reported sick with an oral temperature of ≥38 °C and a cough and/or sore throat. Real-time polymerase chain reaction (PCR) was used to assay for the presence of influenza A and B viruses and adenoviruses (H-AdV), and conventional PCR used for the remaining respiratory viruses in all specimens.

Results

Influenza A virus was the dominant infection with a laboratory-confirmed incidence of 24% (326/1354) and a predominance of the H3N2 subtype. The temporal pattern for influenza A virus infections coincided with the nation-wide pattern in the civilian community. Detection rates of 12% (159/1354) and 2.7% (5/1354) were obtained for influenza B virus and other respiratory viruses, respectively.

Conclusions

The laboratory findings identified influenza A virus as the primary causative viral agent for FRI in the Singapore military, in strong contrast to findings from temperate countries and countries where recruits are often vaccinated for influenza. Our results suggest that influenza vaccination should be considered as a requirement to reduce the incidence of influenza infections. This is the first report describing respiratory infections in a tropical military setting, in a developed country in Asia.

Adenovirus 36 seropositivity is strongly associated with race and gender, but not obesity, among US military personnel

BACKGROUND

Although several studies have shown a positive association between evidence of anti-adenovirus 36 (Ad-36) antibodies (Ad-36 exposure) and (1) obesity and (2) serum cholesterol in animals, there is limited research demonstrating this association in humans. There is also limited research on transmission, presentation and demographics of Ad-36 infection.

DESIGN

(1) Body mass (body mass index (BMI)), (2) fasting serum cholesterol and triglyceride levels and (3) demographic characteristics were compared between Ad-36 seropositive and seronegative groups. The majority of subjects were matched as cases versus controls on a number of demographic variables.

SUBJECTS

A total of 150 obese and 150 lean active-duty military personnel were studied.

MEASUREMENTS

Subjects completed a questionnaire regarding demographic and behavioral characteristics. Subject serum samples were tested by serum neutralization assay for the presence of anti-Ad-36 antibodies.

RESULTS

In all, 34% of obese and 39% of lean subjects had Ad-36 exposure, an insignificant difference. Serum cholesterol and triglyceride levels were significantly higher among the obese subjects than among the lean, but there were no associations between serum cholesterol and triglyceride levels and Ad-36 exposure. Positive associations were found between Ad-36 exposure and age, race and gender.

CONCLUSION

The study stands in contrast to previous work that has shown a positive relationship between Ad-36 exposure and (1) obesity, and (2) levels of serum cholesterol and triglycerides. In this study there was no association in either case. Unanticipated relationships between Ad-36 exposure and age, race and gender were found, and this is the first time that such a link between Ad-36 exposure and demographics has been found.

Etiology of acute undifferentiated febrile illness in the Amazon basin of Ecuador

We conducted a longitudinal observational study of 533 patients presenting to two hospitals in the Ecuadorean Amazon basin with acute undifferentiated febrile illness (AUFI) from 2001 through 2004. Viral isolation, reverse transcription-polymerase chain reaction (RT-PCR), IgM seroconversion, and malaria smears identified pathogens responsible for fever in 122 (40.1%) of 304 patients who provided both acute and convalescent blood samples. Leptospirosis was found in 40 (13.2%), malaria in 38 (12.5%), rickettsioses in 18 (5.9%), dengue fever in 16 (5.3%), Q fever in 15 (4.9%), brucellosis in 4 (1.3%), Ilhéus infection in 3 (1.0%), and Venezuelan equine encephalitis (VEE), Oropouche, and St. Louis encephalitis virus infections in less than 1% of these patients. Viral isolation and RT-PCR on another 229 participants who provided only acute samples identified 3 cases of dengue fever, 2 of VEE, and 1 of Ilhéus. None of these pathogens, except for malaria, had previously been detected in the study area.

Exploration of the effectiveness of social distancing on respiratory pathogen transmission implicates environmental contributions

Background. In both military and civilian settings, transmission of respiratory pathogens may be due to person-to-person and environmental contributions. This possibility was explored in a military training setting, where rates of febrile respiratory illness (FRI) often reach epidemic levels.

Methods. Population size and FRI rates were monitored over 10 months in the units of 50–90 individuals. Some units were open to the influx of potentially infectious convalescents (hereafter referred to as “open units,” and some were closed to such an influx (hereafter referred to as “closed units”). Virologic testing and polymerase chain reaction analysis were used to detect adenovirus on surface structures.

Results. The odds ratio (OR) associated with FRI in closed units, compared with open units, was 1.13 (95% confidence interval [CI], 0.99–1.28). The OR in units with a population greater than the median size, compared with units with a population lower than the median size was 1.38 (95% CI, 1.23–1.55). Between 5% and 9% of surface samples obtained from selected units harbored viable adenovirus.

Conclusions. FRI rates were not reduced in units that were closed to potentially contagious individuals. These findings imply that the primary source of the pathogen is likely environmental rather than human, and they underscore what is known about other virus types. Diligence in identifying the relative roles of different transmission routes is suggested for civilian settings similar to those described in the current study.

Abrupt emergence of diverse species B adenoviruses at US military recruit training centers

BACKGROUND

Adenoviruses (Ads) cause continuous outbreaks of acute respiratory disease (ARD) in US military training facilities. In 1996, the loss of vaccines targeting the dominant recruit-associated serotypes precipitated the reemergence of Ads in these populations. Between 1999 and 2002, serotype 4 accounted for >95% of Ads isolated from recruits and for >50% of ARD cases in training facilities (15,000 cases/year).

METHODS

Ads (n=1867) collected between 2002 and 2006 from recruits with ARD at 8 military training facilities in the United States were serotyped by serum neutralization and polymerase chain reaction.

RESULTS

The dominance of Ad4 continued through 2005, followed by a simultaneous emergence of diverse species B serotypes at the majority of sites. This included the subspecies B1 serotypes 3, 7, and 21 and the subspecies B2 serotype 14. Ad14 was the most prevalent species B serotype, appearing in high numbers at 3 sites and becoming dominant at 1.

CONCLUSIONS

Subspecies B2 Ads have rarely been associated with ARD, and only in Eurasia. This survey represents the first report of AdB2-associated ARD in the Western Hemisphere. The simultaneous emergence of several species B Ads suggests a common external source (the civilian population) and a decrease in preexisting immunity to species B Ads.

Genotype prevalence and risk factors for severe clinical adenovirus infection, United States 2004-2006

BACKGROUND

Recently, epidemiological and clinical data have revealed important changes with regard to clinical adenovirus infection, including alterations in antigenic presentation, geographical distribution, and virulence of the virus.

METHODS

In an effort to better understand the epidemiology of clinical adenovirus infection in the United States, we adopted a new molecular adenovirus typing technique to study clinical adenovirus isolates collected from 22 medical facilities over a 25-month period during 2004-2006. A hexon gene sequence typing method was used to characterize 2237 clinical adenovirus-positive specimens, comparing their sequences with those of the 51 currently recognized prototype human adenovirus strains. In a blinded comparison, this method performed well and was much faster than the classic serologic typing method.

RESULTS

Among civilians, the most prevalent adenovirus types were types 3 (prevalence, 34.6%), 2 (24.3%), 1 (17.7%), and 5 (5.3%). Among military trainees, the most prevalent types were types 4 (prevalence, 92.8%), 3 (2.6%), and 21 (2.4%).

CONCLUSIONS

For both populations, we observed a statistically significant increasing trend of adenovirus type 21 detection over time. Among adenovirus isolates recovered from specimens from civilians, 50% were associated with hospitalization, 19.6% with a chronic disease condition, 11% with a bone marrow or solid organ transplantation, 7.4% with intensive care unit stay, and 4.2% with a cancer diagnosis. Multivariable risk factor modeling for adenovirus disease severity found that age <7 years (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.4-7.4), chronic disease (OR, 3.6; 95% CI, 2.6-5.1), recent transplantation (OR, 2.7; 95% CI, 1.3-5.2), and adenovirus type 5 (OR, 2.7; 95% CI, 1.5-4.7) or type 21 infection (OR, 7.6; 95% CI, 2.6-22.3) increased the risk of severe disease.

Influenza vaccine effectiveness among US military basic trainees, 2005-06 season

Virtually all US military basic trainees receive seasonal influenza vaccine. Surveillance data collected from December 2005 through March 2006 were evaluated to estimate effectiveness of the influenza vaccine at 6 US military basic training centers. Vaccine effectiveness against laboratory-confirmed influenza was 92% (95% confidence interval 85%-96%).

Global surveillance of emerging Influenza virus genotypes by mass spectrometry

BACKGROUND

Effective influenza surveillance requires new methods capable of rapid and inexpensive genomic analysis of evolving viral species for pandemic preparedness, to understand the evolution of circulating viral species, and for vaccine strain selection. We have developed one such approach based on previously described broad-range reverse transcription PCR/electrospray ionization mass spectrometry (RT-PCR/ESI-MS) technology.

METHODS AND PRINCIPAL FINDINGS

Analysis of base compositions of RT-PCR amplicons from influenza core gene segments (PB1, PB2, PA, M, NS, NP) are used to provide sub-species identification and infer influenza virus H and N subtypes. Using this approach, we detected and correctly identified 92 mammalian and avian influenza isolates, representing 30 different H and N types, including 29 avian H5N1 isolates. Further, direct analysis of 656 human clinical respiratory specimens collected over a seven-year period (1999-2006) showed correct identification of the viral species and subtypes with >97% sensitivity and specificity. Base composition derived clusters inferred from this analysis showed 100% concordance to previously established clades. Ongoing surveillance of samples from the recent influenza virus seasons (2005-2006) showed evidence for emergence and establishment of new genotypes of circulating H3N2 strains worldwide. Mixed viral quasispecies were found in approximately 1% of these recent samples providing a view into viral evolution.

CONCLUSION/SIGNIFICANCE

Thus, rapid RT-PCR/ESI-MS analysis can be used to simultaneously identify all species of influenza viruses with clade-level resolution, identify mixed viral populations and monitor global spread and emergence of novel viral genotypes. This high-throughput method promises to become an integral component of influenza surveillance.

Molecular epidemiology of adenovirus type 4 infections in US military recruits in the postvaccination era (1997-2003)

BACKGROUND

Military recruits are at a higher risk of respiratory infection than their civilian counterparts. Continuous outbreaks of adenovirus (Ad)-associated acute respiratory disease were documented among US trainees before the implementation of serotype 4 (Ad4) and serotype 7 vaccines in 1971. The discontinuation of Ad vaccination programs in 1999 precipitated the reemergence of Ad in training sites, with Ad4 accounting for 98% of all diagnosed cases.

METHODS

A total of 724 Ad4 strains isolated from recruits presenting with febrile respiratory illness at 8 training sites nationwide between 1997 and 2003 were genome typed by restriction enzyme analysis.

RESULTS

Seven genome types were identified, all of which were distinct from the prototype Ad4p and the vaccine type 4p1. Results showed very different, and often stable, genome type distributions at different geographic sites, despite the homogeneity of the recruit source population.

CONCLUSIONS

The data support the hypothesis that reservoirs for Ad outbreaks are within recruit training sites or in their immediate environments, not in the incoming recruit population. Molecular characterization beyond serotype is critical to understanding the transmission dynamics of Ad infection in these unique susceptible populations and to the implementation of effective prevention approaches.

Application of broad-spectrum, sequence-based pathogen identification in an urban population

A broad spectrum detection platform that provides sequence level resolution of target regions would have a significant impact in public health, case management, and means of expanding our understanding of the etiology of diseases. A previously developed respiratory pathogen microarray (RPM v.1) demonstrated the capability of this platform for this purpose. This newly developed RPM v.1 was used to analyze 424 well-characterized nasal wash specimens from patients presenting with febrile respiratory illness in the Washington, D. C. metropolitan region. For each specimen, the RPM v.1 results were compared against composite reference assay (viral and bacterial culture and, where appropriate, RT-PCR/PCR) results. Across this panel, the RPM assay showed >or=98% overall agreement for all the organisms detected compared with reference methods. Additionally, the RPM v.1 results provide sequence information which allowed phylogenetic classification of circulating influenza A viruses in approximately 250 clinical specimens, and allowed monitoring the genetic variation as well as antigenic variability prediction. Multiple pathogens (2-4) were detected in 58 specimens (13.7%) with notably increased abundances of respiratory colonizers (esp. S. pneumoniae) during viral infection. This first-ever comparison of a broad-spectrum viral and bacterial identification technology of this type against a large battery of conventional "gold standard" assays confirms the utility of the approach for both medical surveillance and investigations of complex etiologies of illness caused by respiratory co-infections.

A cluster of Legionella-associated pneumonia cases in a population of military recruits

A Legionella cluster was identified through retrospective PCR analysis of 240 throat swab samples from X-ray-confirmed pneumonia cases. These were identified among young and otherwise healthy U.S. military recruits during population-based surveillance for pneumonia pathogens. Results were confirmed by sequence analysis. Cases clustered tightly, suggesting a local environmental etiology.

Asthma hospitalizations among US military personnel, 1994 to 2004

BACKGROUND

Acute asthma attacks strike unpredictably and may lead to hospitalization in otherwise healthy individuals. The burden of asthma hospitalization on the US health care system has greatly interested health care workers, many of whom see the incidence of asthma as increasing.

OBJECTIVES

To examine the annual incidence of hospitalization and the frequency of subsequent hospitalization for asthma among all active-duty US military personnel between 1994 and 2004 and to determine demographic and occupational risk factors of asthma hospitalization within this generally healthy US population.

METHODS

Annual demographic and occupational data were combined with electronic hospitalization records for patients with a discharge diagnosis of asthma. Using Cox proportional hazard modeling, the authors investigated demographic and occupational risk factors for asthma hospitalization.

RESULTS

Women, married persons, health care workers, enlisted personnel, US Army personnel, and older persons were found to have a significantly greater risk of asthma hospitalization. Yearly rates of hospitalization declined from 22.3 per 100,000 persons to 12.6 per 100,000 persons between 1994 and 2004.

CONCLUSIONS

Although these data have some limitations, they suggest that the burden of asthma hospitalizations in the large, healthy population of US military personnel has declined during the last decade. The decrease in hospitalization potentially reflects improved outpatient management strategies.

Using a resequencing microarray as a multiple respiratory pathogen detection assay

Simultaneous testing for detection of infectious pathogens that cause similar symptoms (e.g., acute respiratory infections) is invaluable for patient treatment, outbreak prevention, and efficient use of antibiotic and antiviral agents. In addition, such testing may provide information regarding possible coinfections or induced secondary infections, such as virally induced bacterial infections. Furthermore, in many cases, detection of a pathogen requires more than genus/species-level resolution, since harmful agents (e.g., avian influenza virus) are grouped with other, relatively benign common agents, and for every pathogen, finer resolution is useful to allow tracking of the location and nature of mutations leading to strain variations. In this study, a previously developed resequencing microarray that has been demonstrated to have these capabilities was further developed to provide individual detection sensitivity ranging from 10(1) to 10(3) genomic copies for more than 26 respiratory pathogens while still retaining the ability to detect and differentiate between close genetic neighbors. In addition, the study demonstrated that this system allows unambiguous and reproducible sequence-based strain identification of the mixed pathogens. Successful proof-of-concept experiments using clinical specimens show that this approach is potentially very useful for both diagnostics and epidemic surveillance.

Fifteen-year study of the changing epidemiology of methicillin-resistant Staphylococcus aureus

PURPOSE

The study's purpose was to elucidate the evolutionary, microbiologic, and clinical characteristics of methicillin-resistant Staphylococcus aureus (MRSA) infections.

METHODS

MRSA cases from military medical facilities in San Diego, from 1990 to 2004, were evaluated and categorized as community-acquired or nosocomial. Sequence type, staphylococcal chromosomal cassette gene type, and Panton-Valentine leukocidin gene status were determined for a subset of isolates.

RESULTS

Over the 15-year period, 1888 cases of MRSA were identified; 65% were community acquired. The incidence (155 infections/100000 person-year in 2004) and household-associated cases rapidly increased since 2002. Among persons with community-acquired MRSA, 16% were hospitalized and only 17% were initially given an effective antibiotic. Community-acquired MRSA cases compared with nosocomial MRSA cases were more often soft-tissue and less often urinary, lung, or bloodstream infections (P<.001). Patients with community-acquired MRSA were younger (22 vs 64 years, P<.001) and less likely to have concurrent medical conditions (9% vs 98%, P<.001). Clindamycin resistance increased among community-acquired MRSA isolates during 2003 and 2004 compared with previous years (79% vs 13%, P<.001). Genetically, nosocomial MRSA isolates were significantly different than those acquired in the community. Although community-acquired MRSA isolates were initially diverse by 2004, one strain (staphylococcal chromosomal cassette type IV, sequence type 8, Panton-Valentine leukocidin gene positive) became the predominant isolate.

CONCLUSIONS

Community-acquired and intrafamilial MRSA infections have increased rapidly since 2002. Our 15 years of surveillance revealed the emergence of distinct community-acquired MRSA strains that were genetically unrelated to nosocomial MRSA isolates from the same community.

Diagnostic discrimination of live attenuated influenza vaccine strains and community-acquired pathogenic strains in clinical samples

Live vaccines can generate false-positive results on common influenza assays including reverse transcriptase-PCR (RT-PCR), culture and antigen tests. This threatens the integrity of epidemiological data and may misdirect treatment and control efforts. We report the development of RT-PCR tests that distinguish live FluMist vaccine (FMV) strains from circulating influenza strains in clinical samples. Primers were validated using influenza-positive samples from unvaccinated patients, packaged FMV, and one PCR-positive asymptomatic vaccine. Furthermore, the assay was used to experimentally test our lab's collection of influenza-positive samples from the 2004-05 and 2005-06 influenza seasons and several 2005 preseason isolates to determine the rate of vaccine-derived false-positive results under differing epidemiological conditions. Analytical and clinical validations show that the assay is both sensitive and specific. Experimental results demonstrate that 51 out of 51 influenza-positive samples collected during influenza season from ill, previously-vaccinated military personnel represent real infections with circulating strains. Finally, the assay shows that four preseason influenza-positive samples were false positives resulting from vaccine shedding. The vaccine-discriminatory RT-PCR methods described here provide the first test designed to distinguish FMV strains from circulating strains. The results show that the test is effective, and demonstrate the importance of such tests in the age of live vaccines.

Genetic relationships among Mayaro and Una viruses suggest distinct patterns of transmission

Mayaro and Una viruses (MAYV, UNAV) are mosquito-borne alphaviruses that may cause an acute febrile illness characterized by headache, retro-orbital pain, and rash that may progress to a severe and prolonged arthralgia. MAYV was first isolated in Trinidad in 1954, and UNAV was first identified in northern Brazil in 1959. Since then, numerous isolates of these agents have been made from humans, wild vertebrates, and mosquitoes in several countries in northern South America. Serological evidence suggests that these viruses are also present in portions of Central America. Because little is known about the natural transmission cycle of MAYV and virtually nothing is known about UNAV transmission, 63 isolates covering the known geographic and temporal ranges were used in phylogenetic analyses to aid in understanding the molecular epidemiology. Approximately 2 kb from the E1 and E2 glycoprotein genes and the complete 3' non-coding region were sequenced. Phylogenetic analyses of these sequences indicated that two distinct genotypes of MAYV exist with a distinct clade consisting exclusively of UNAV (previously designated as a subtype of MAYV). One MAYV genotype (genotype D) contains isolates from Trinidad and the northcentral portion of South America including Peru, French Guiana, Surinam, Brazil, and Bolivia. All of these isolates are highly conserved with a nucleotide divergence of < 6%. The second MAYV genotype (genotype L) contains isolates only from Brazil that are highly conserved (< 4% nucleotide divergence) but are quite distinct (15-19%) from the first genotype isolates. These analyses provide possible explanations for the natural ecology and transmission of MAYV and UNAV.

Transmission dynamics and prospective environmental sampling of adenovirus in a military recruit setting

BackgroundHigh levels of morbidity caused by adenovirus among US military recruits have returned since the loss of adenovirus vaccines in 1999. The transmission dynamics of adenovirus have never been well understood, which complicates prevention efforts

MethodsEnrollment and end-of-study samples were obtained and active surveillance for febrile respiratory illnesses (FRIs) was performed for 341 recruits and support personnel. Environmental samples were collected simultaneously. Classic and advanced diagnostic techniques were used

ResultsSeventy-nine percent (213/271) of new recruits were seronegative for either adenovirus serotype 4 (Ad-4) or adenovirus serotype 7 (Ad-7). FRI caused by Ad-4 was observed in 25% (67/271) of enrolled recruits, with 100% of them occurring in individuals with enrollment titers <1:4. The percentage of recruits seropositive for Ad-4 increased from 34% at enrollment to 97% by the end of the study. Adenovirus was most commonly detected in the environment on pillows, lockers, and rifles

ConclusionsPotential sources of adenovirus transmission among US military recruits included the presence of adenovirus on surfaces in living quarters and extended pharyngeal viral shedding over the course of several days. The introduction of new recruits, who were still shedding adenovirus, into new training groups was documented. Serological screening could identify susceptible recruits for the optimal use of available vaccines. New high-throughput technologies show promise in providing valuable data for clinical and research applications