Enhanced risk of illness during the 1918 influenza pandemic after previous influenza-like illnesses in three military populations.

The reasons for the unprecedented mortality during the 1918 influenza pandemic remain poorly understood. We examined morbidity records from three military cohorts from years prior to and during the 1918 pandemic period to assess the effects of previous respiratory illnesses on experiences during the pandemic. Clinical registers and morbidity lists were examined to identify all medical encounters for acute respiratory illnesses in students at two U.S. military officer training academies and Australian soldiers deployed in Europe. Influenza-like illness prior to the major pandemic wave of 1918 predisposed Australian soldiers [relative risk (RR) 1·37, 95% confidence interval (CI) 1·18-1·60, P < 0·0001] and US officer trainees at West Point (RR 3·10, 95% CI 2·13-4·52, P < 0·0001) and Annapolis (RR 2·03, 95% CI 1·65-2·50, P < 0·0001) to increased risks of medically treated illnesses in late 1918. The findings suggest that susceptibility to and/or clinical expressions of the 1918 pandemic influenza virus depended on previous experiences with respiratory infectious agents. The findings are consistent with observations during the 2009 pandemic in Canada and may reflect antibody-dependent enhancement of influenza infection.

Pacific islands which escaped the 1918-1919 influenza pandemic and their subsequent mortality experiences.

Very few Pacific islands escaped the 1918-1919 influenza pandemic. Subsequent influenza epidemics in the established colonial outposts of American Samoa and New Caledonia infected many but killed very few persons whereas the extraordinarily isolated Niue, Rotuma, Jaliut and Yule islands experienced high mortality influenza epidemics (>3% of population) following 1918. These dichotomous outcomes indicate that previous influenza exposure and degree of epidemiological isolation were important mortality risk factors during influenza epidemics on Pacific islands.

The nature, incidence, and impact of eye injuries among US military personnel: implications for prevention.

OBJECTIVES: To assess incidence rates of eye injuries in the US Armed Forces and to identify demographic and occupational correlates of risk. DESIGN: Retrospective population-based study. SETTING: US military medical facilities worldwide. PARTICIPANTS: All individuals in the US Armed Forces during 1998. MAIN OUTCOME MEASURES: Incidence rates of hospitalizations and ambulatory visits for eye injuries. RESULTS: The incidence rate of ambulatory visits (983 per 100 000 person-years) for eye injuries was 58 times higher than the incidence rate of hospitalizations (17 per 100 000 person-years) for eye injuries. Orbital floor fractures, contusions, and open wounds to the ocular adnexa and orbit accounted for 85% of eye injuries resulting in hospitalization, while 80% of ambulatory visits were for superficial wounds and foreign bodies. Hospitalization rates varied widely across demographic subgroups. Men had twice the incidence rate as women, and the youngest age group (17-24 years) had 6 times the incidence rate of the oldest age group (35-65 years). Together, motor vehicle crashes and fights caused nearly half of the hospitalizations. Ambulatory rates varied significantly in relation to occupation but not to demography. Tradespeople (eg, metal body machinist, welder, and metalworker) had incidence rates 3 to 4 times higher than the overall population rate. CONCLUSIONS: Hospitalization and ambulatory data provide different views of the morbidity associated with eye injuries. General safety precautions and behavior modification, rather than eye-specific interventions, are indicated to prevent the most serious eye injuries. However, the consistent use of eye protection during known hazardous occupational activities could prevent much of the morbidity associated with the less serious, yet more common, eye injuries.

Incidence of recurrent diagnoses of Chlamydia trachomatis genital infections among male and female soldiers of the US Army.

BACKGROUND/OBJECTIVES: Few studies of Chlamydia trachomatis incidence, especially among men, and most studies of C. trachomatis in US military populations are cross sectional prevalence surveys. A population based retrospective cohort was used to determine risk factors for repeat diagnoses of genital C. trachomatis infections among male and female soldiers with previous C. trachomatis infections. METHODS: All active duty soldiers diagnosed with C. trachomatis genital infections between 1994 and 1998. Cohort members were passively followed until repeat diagnoses of C. trachomatis infection, termination of army service, or the end of the study. RESULTS: Among 11,771 soldiers with initial diagnoses of chlamydia, the crude rate of repeat diagnoses was 52.0 per 1000 person years. Women and men aged 20-24 were at greatest unadjusted risk of reinfection. After adjustment, women aged 20-24 and men aged 25-29 were at higher risk than their younger or older counterparts. CONCLUSIONS: Results of this study suggest that both male and female soldiers who are diagnosed with chlamydia infections have relatively high risks of reinfection through their 20s.

Hospitalizations for all causes of U.S. military service members in relation to participation in Operations Joint Endeavor and Joint Guard, Bosnia-Herzegovina, January 1995 to December 1997.

Since December 1995, the United States has deployed military forces to Bosnia-Herzegovina to participate for varying periods in peacekeeping operations. Throughout the operations, medical surveillance data have been routinely integrated in the Defense Medical Surveillance System. For this analysis, all individuals who served in the U.S. armed forces between January 1995 and December 1997 were characterized as participants or nonparticipants in the Bosnia-Herzegovina operations. Each participant's service was divided into predeployment, deployment, and postdeployment phases. End points for analyses were hospitalizations (all causes) in military hospitals. The crude hospitalization rate among nonparticipants (80.9 per 1,000 person-years [p-yrs]) exceeded the rate among participants (56.6 per 1,000 p-yrs). Among participants, the crude hospitalization rate during deployment (84.4 per 1,000 p-yrs) exceeded the rates before deployment (54.7 per 1,000 p-yrs) and after deployment (49.9 per 1,000 p-yrs). Proportional hazards regression procedures were used to control for confounding effects in comparisons of participants and nonparticipants, to account for transitions in deployment-phase exposures at appropriate calendar times, and to adjust for changes in hospitalization criteria that were implemented during the study. Although the crude hospitalization rate after deployment was lower than the rate before deployment, adjusted relative risks were elevated during and after deployment (relative to before deployment).

Efficacy testing of recombinant human immunodeficiency virus (HIV) gp160 as a therapeutic vaccine in early-stage HIV-1-infected volunteers. rgp160 Phase II Vaccine Investigators.

A phase II efficacy trial was conducted with recombinant human immunodeficiency virus (HIV) type 1 envelope glycoprotein gp160 (rgp160) in 608 HIV-infected, asymptomatic volunteers with CD4+ cell counts >400 cells/mm3. During a 5-year study, volunteers received a 6-shot primary series of immunizations with either rgp160 or placebo over 6 months, followed by booster immunizations every 2 months. Repeated vaccination with rgp160 was safe and persistently immunogenic. Adequate follow-up and acquisition of endpoints allowed for definitive interpretation of the trial results. There was no evidence that rgp160 has efficacy as a therapeutic vaccine in early-stage HIV infection, as measured at primary endpoints (50% decline in CD4+ cell count or disease progression to Walter Reed stage 4, 5, or 6) or secondary endpoints. A transient improvement was seen in the secondary CD4 endpoint for the vaccination compared with the placebo arm, but this did not translate into improved clinical outcome.

Injuries in the military: a review and commentary focused on prevention.

BACKGROUND: In November 1996, the Armed Forces Epidemiological Board (AFEB) Injury Prevention and Control Work Group issued a report that cited injuries as the leading cause of morbidity and mortality among military service members. This article reviews the types and categories of military morbidity and mortality data examined by the AFEB work group and the companion Department of Defense (DoD) Injury Surveillance and Prevention Work Group. This article further uses the injury data reviewed to illustrate the role of surveillance and research in injury prevention. The review provides the context for discussion of the implications of the AFEB work group's findings for the prevention of injuries in the military. METHODS: The AFEB work group consisted of 11 civilian injury epidemiologists, health professionals and scientists from academia, and other non-DoD government agencies, plus six military liaison officers. Injury data from medical databases were provided to the civilian experts on the AFEB work group by the all-military DoD Injury Surveillance and Prevention Work Group. The AFEB work group assessed the value of each database to the process of prevention and made recommendations for improvement and use of each data source. RESULTS: Both work groups found that injuries were the single leading cause of deaths, disabilities, hospitalizations, outpatient visits, and manpower losses among military service members. They also identified numerous data sources useful for determining the causes and risk factors for injuries. Those data sources indicate that training injuries, sports, falls, and motor vehicle crashes are among the most important causes of morbidity for military personnel. CONCLUSIONS: While the work group recommends ways to prevent injuries, they felt the top priority for injury prevention must be the formation of a comprehensive medical surveillance system. Data from this surveillance system must be used routinely to prioritize and monitor injury and disease prevention and research programs. The success of injury prevention will depend not just on use of surveillance but also partnerships among the medical, surveillance, and safety agencies of the military services as well as the military commanders, other decision makers, and service members whose direct actions can prevent injuries and disease.

Reemergence of adenovirus type 4 acute respiratory disease in military trainees: report of an outbreak during a lapse in vaccination.

From 23 April to 13 May 1995, an outbreak of acute respiratory disease (ARD) hospitalizations occurred in basic training soldiers at Fort Jackson, South Carolina. Weekly hospitalization rates for the most affected military unit reached 11.6%. Virus isolation and serologic studies from a sample of patients identified the agent as adenovirus type 4. Prior to starting vaccinations against adenovirus types 4 and 7 in 1971, these serotypes were the major causes of ARD in basic trainees. No outbreaks were reported when the vaccines were used. A logistical error temporarily interrupted vaccine production, and newly arriving trainees received no adenovirus vaccines from the summer of 1994 through late March 1995. This outbreak occurred in unvaccinated soldiers. The sole manufacturer has permanently stopped adenovirus vaccine production. All type 4 vaccine supplies are now depleted. This outbreak demonstrates continued susceptibility of military recruits to adenovirus type 4 and warns of future outbreaks.

Prevalence of antibodies to adenovirus serotypes 4 and 7 among unimmunized US Army trainees: results of a retrospective nationwide seroprevalence survey.

The 1996 production halt of adenovirus types 4 and 7 vaccines prompted concerns about the resurgence of large respiratory disease outbreaks among US military basic trainees. This serosurvey was conducted to assess the current susceptibility of the trainee population to these viruses. A stratified, random sample (n=303) of trainees' sera was tested using a quantitative colorimetric microneutralization assay to demonstrate antibody titers considered to provide immunologic protection against each adenovirus type. Results were analyzed for relationships between susceptibility and 4 demographic factors-gender, race, prior military service, and age. Results showed that 66% and 73% of trainees were susceptible to serotypes 4 and 7, respectively. Nearly 90% were susceptible to at least one serotype. Susceptibility was significantly (P<.05) related to lack of prior military service and younger age. Consistent with a serosurvey conducted 20 years ago, these results demonstrated significant susceptibility to two vaccine-preventable causes of disease. These findings may have civilian implications.

Survey of U.S. Army soldiers' knowledge, attitudes, and practices regarding personal protection measures to prevent arthropod-related diseases and nuisance bites.

This study examined U.S. Army soldiers' knowledge, attitudes, and practices regarding personal protection measures (PPMs) to prevent arthropod-related diseases and nuisance bites. Soldiers attending 1 of 13 U.S. Army training courses either completed a written questionnaire (N = 1,007) or participated in a group interview (N = 65). Respondents primarily used repellents to prevent nuisance insect bites (55%) rather than to prevent disease (38.7%). Less than one-third correctly identified the military-issue repellents to be used on skin (31.7%) or clothing (26.1%). More than half (57.6%) thought that commercial products were better than military-issue repellents, but most (74.2%) reported that they did not have enough or any information about the U.S. military's system of PPMs. Soldiers have poor knowledge of U.S. military doctrine regarding PPMs and still prefer to use commercial products. A focused strategy to ensure the appropriate use of PPMs by service members should be developed, implemented, and evaluated.

Laboratory evaluation of a dot-blot enzyme immunoassay for serologic confirmation of illness due to Rickettsia conorii.

Of the 169 United States Army soldiers who deployed on a field training exercise to a remote area of Botswana for two weeks in January 1992, more than 30% developed a febrile illness within five days of their return. A diagnosis of South African tick typhus was suggested by soldiers' exposure to ticks, as well as the presence of eschars and vesicles at the site of tick bites, and tender regional lymphadenopathies. This high attack rate, experienced during such a short exposure period, emphasizes the hazard of illness due to Rickettsia conorii to persons visiting endemic areas. A rapid, diagnostic, semiquantitative enzyme immunoassay (DS) for detection of IgG and IgM antibodies to R. conorii was performed on 209 acute and convalescent sera from soldiers in the outbreak and on 75 control sera. For the acute sera from soldiers meeting the probable case definition of having both regional lymphadenopathy and tick bite eschar, as judged by an IgG indirect fluorescent antibody (IFA) test, the resulting sensitivity and specificity of the DS test were 100% and 48%, respectively. In the analysis of the acute sera, the DS test identified as reactive more of the probable cases (62%) than either the IgG (16%) or IgM (55%) IFAs. This simple and rapid diagnostic test could be useful in establishing a preliminary diagnosis of R. conorii rickettsiosis in remote settings when immediate confirmation by IFA is impossible.

Military preventive medicine and medical surveillance in the post-cold war era.

In response to the end of the cold war, the United States developed new foreign policy and national security strategies. As a result, many medical support concepts that were operative during the cold war were invalidated. Recently, the Chairman of the Joint Chiefs of Staff provided direction and guidance for long-range strategic planning (Joint Vision 2010). Medical support doctrine that is being developed within the framework of Joint Vision 2010 relies on currently unavailable preventive medicine and medical surveillance capabilities. This report analyzes the relevance and roles of military preventive medicine and medical surveillance in the context of post-cold war resource constraints and military medical support needs, presents the rationale for and objectives of a demand-reduction medical support strategy, and outlines the roles, responsibilities, and characteristics of a defense medical surveillance system.

Deployed US Army soldiers' knowledge and use of personal protection measures to prevent arthropod-related casualties.

The recommendation to use personal protection measures (PPMs) to prevent arthropod-related diseases and nuisance bites is a common element of travel medicine consultation.1-3 Prevention of arthropod-related casualties is especially important to the military, given the often intense exposure of service members to biting arthropods and the threat of personnel losses to mission success. In the 1980s, 75% deet (N,N-diethyl-m-toluamide) was the US military-issue insect repellent for use on skin and clothing. Collaboration between military and civilian researchers led to the implementation in 1991 of the current US military system of PPMs which has three components: topical application of 33% extended-duration deet, treatment of field uniforms with permethrin, and proper wearing of field uniforms.4-6 Compared to military-issue 75% topical deet, 33% extended-duration deet prevents bites up to three times longer (as long as 12 hours), is less greasy, and has lower plasticizing properties. Field uniforms treated with the contact toxicant, permethrin, are also necessary to minimize bites from crawling arthropods such as ticks and chiggers. Implementation of all three components of this system is a safe and effective means of reducing the threat posed by biting arthropods.7 We conducted a questionnaire survey to assess the degree of deployed soldiers' knowledge of the US military's system of PPMs and use of PPMs in general. Survey results may promote the development of better ways to advise and teach military and civilian travelers about the proper use of PPMs given the multitude of available products and practices.

Children of human immunodeficiency virus-infected members of the Army Reserve components.

OBJECTIVES: Little is known about the numbers of children who will be left without one or both parents because of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome. This report evaluates childbearing patterns among U.S. Army reserve component members, a group largely made up of men with limited contact with the military. METHODS: HIV status was determined from routinely collected data, with demographic information obtained from personnel records. Number of children was estimated from number of dependents reported. No information was available on the infection status of children or spouses of members. RESULTS: There were 1,884 HIV-positive members, with an estimated total of 843 children. Childbearing patterns varied across several demographic characteristics. Among 14 metropolitan statistical areas, the proportion reporting any children and the number of children of infected members per 100,000 varied substantially. CONCLUSIONS: This report documents the numbers of children of HIV-positive adults in this population and provides evidence that certain metropolitan areas will be disproportionately affected.

Suicide and HIV infection. Mortality follow-up of 4147 HIV-seropositive military service applicants.

OBJECTIVE: To examine the risk of suicide among individuals positive for the human immunodeficiency virus (HIV) following screening for evidence of HIV infection. Prior studies have reported a 7- to 36-fold increased risk of suicide for persons with the acquired immunodeficiency syndrome. DESIGN: Prospective cohort study. SETTING: Military service applicants from throughout the United States. MAIN OUTCOME MEASURE: Death from suicide. METHODS: The National Death Index was searched for mortality among 4147 HIV-positive military service applicants and 12437 HIV-negative applicants disqualified from military service due to other medical conditions (matched 1:3 on age, race, sex, and screening date and location) identified by the US Department of Defense between October 1985 and December 1993. Death certificates were obtained from individual states. Identifiers and HIV status of living applicants were known only by the Department of Defense. RESULTS: The HIV-positive applicants were 92% male, 37% white, and 56% black. Median age was 24 years (range, 17-57 years). Median follow-up time was 70 months (range, 0-99 months). Ten HIV-positive (49 per 100 000 person-years) and 24 HIV-negative applicants (36 per 100 000 person-years) died of suicide (rate ratio [RR], 1.35; 95% confidence interval [CI]= 0.58-2.93). Suicide rates among both HIV-positive (RR, 2.08; 95% CI, 1.00-3.82) and HIV-negative (RR, 1.67; 95% CI, 1.07-2.48) applicants are marginally higher than those for the US general population, after adjustment for age, race, and sex. Time from screening to death was less than 3 months for 3 of 10 HIV-positive and 2 of 24 HIV-negative applicants who died of suicide. CONCLUSIONS: The HIV-positive individuals do not appear to have a significantly increased risk of death from suicide in the months following HIV screening in this study population. Because suicide risk is reported to be greatly increased after symptomatic HIV disease is present, clinicians should consider asking persons with HIV infection about suicide risk factors during both initial counseling and subsequent medical care.

Epidemiology and control of acute respiratory diseases with emphasis on group A beta-hemolytic streptococcus: a decade of U.S. Army experience.

OBJECTIVE: To summarize the experiences of the U.S. Army regarding prevention and control, and frequencies, rates, trends, and determinants of febrile acute respiratory diseases (ARDs), particularly Group A beta-hemolytic streptococcus (GABHS). METHODOLOGY: Since 1966, the U.S. Army has conducted routine surveillance of ARDs among basic trainees. Since 1985, all trainees with fever and respiratory tract symptoms have been cultured for GABHS: Field investigations were conducted when outbreaks of acute respiratory or GABHS-associated illnesses were detected. Mass plus tandem benzathine penicillin prophylaxis were used to interdict and control training center GABHS outbreaks. RESULTS: During the period 1985 to 1994, there were 65,184 hospitalizations for acute febrile respiratory illnesses among Army trainees. The crude hospitalization rate was 0.45 per 100 trainees per week. The rate consistently declined over the period. Incremental declines were temporally associated with increased use of adenovirus immunizations and broader use of benzathine penicillin prophylaxis. During the period, 10,789 of 59,818 (18%) pharyngeal cultures were positive for GABHS: GABHS outbreaks were associated with diverse clinical manifestations including streptococcal toxic shock, acute rheumatic fever, and pneumonia. The emergence of mucoid colony morphology in clinical isolates was a consistent indicator of circulating virulent strains with epidemic potential. Outbreak-associated M types were M1, M3, M5, and M18. In response to six GABHS outbreaks, mass plus tandem benzathine penicillin chemoprophylaxis produced rapid and sustained GABHS control. ARD and GABHS recovery rates were lowest when benzathine penicillin prophylaxis was widely used. CONCLUSIONS: ARD rates among Army trainees have consistently declined to unprecedented levels. GABHS has reemerged as an important threat to military trainees. Benzathine penicillin chemoprophylaxis is safe and effective for interdicting and preventing GABHS outbreaks in closed, healthy young adult populations.

The U.S. Army HIV testing program: the first decade.

In response to the human immunodeficiency virus (HIV) epidemic, the U.S. military established comprehensive policies to protect individual and public health and to assure military readiness. Central to this effort was the creation of a total-force HIV screening program. As representative of these military programs, the U.S. Army's HIV testing program is described. The first decade of this program is assessed from financial, research, policy, and epidemic-control perspectives. We conclude that the government's investment has been a prudent one, leaving the U.S. military better positioned to counter the threats posed by the HIV pandemic.

Comparative mortality among US military personnel in the Persian Gulf region and worldwide during Operations Desert Shield and Desert Storm.

OBJECTIVE: To determine cause-specific mortality rates among US troops stationed in the Persian Gulf region and compare them with those of US troops serving elsewhere during Operations Desert Shield and Desert Storm. DESIGN: Retrospective cohort. POPULATION: US men and women on active duty from August 1, 1990, through July 31, 1991. MAIN OUTCOME MEASURES: Deaths occurring among all active-duty US military persons during the 1-year study period. Age-adjusted mortality rates among US troops stationed in the Persian Gulf region were compared with rates projected from mortality rates among troops on active duty elsewhere. RESULTS: A total of 1769 active-duty persons died during the study period, 372 in the Persian Gulf region and 1397 elsewhere. Of the 372 deaths in the Persian Gulf region, 147 (39.5%) occurred as a direct result of combat during the war, 194 (52.2%) resulted from injuries not incurred in battle, and 30 (8%) resulted from illness. Twenty-three of the deaths due to illness were considered unexpected or cardiovascular deaths. Based on age-adjusted mortality rates observed among US troops on active duty outside the Persian Gulf region, 165 deaths from unintentional injury and 32 deaths from illness (20 of which were unexpected or cardiovascular) would have been anticipated among Persian Gulf troops. CONCLUSION: Except for deaths from unintentional injury, US troops in the Persian Gulf region did not experience significantly higher mortality rates than US troops serving elsewhere. There were no clusters of unexplained deaths. The number and circumstances of nonbattle deaths among Persian Gulf troops were typical for the US military population.