Epidemic of adenovirus-induced respiratory illness among US military recruits: epidemiologic and immunologic risk factors in healthy, young adults.

Adenovirus (Ad)-induced acute respiratory illnesses resurged among civilian adults and selected military training populations in the United States during the late 1990s. We examined the epidemiologic and immunologic correlates of Ad-induced respiratory illnesses during a large outbreak at an Army basic training installation in southeast United States during a 9-day period in November 1997. A total of 79 recruits hospitalized with acute respiratory illnesses were evaluated during the outbreak period; confirmation of Ad infection by isolation of Ad-like cytopathic agents from throat cultures was detected in 71 (90%) of these patients. Serotyping of 19 (27%) of these 71 isolates identified the etiologic agent to be Ad type 4 (Ad4). In addition, 30 (81%) of 37 patients in whom paired sera were collected demonstrated significant increases (i.e., 4-fold or higher) in serum anti-Ad4 neutralizing antibodies. Anti-Ad4 immunity in new recruits was found to be very low (15 to 22%). A case-control study involving 66 of the 79 hospitalized cases and 189 non-ill controls from the same units was conducted. A lower risk of hospitalization for acute respiratory illnesses was documented for female recruits (odds ratio[OR] = 0.47, P <.05) whereas, a higher risk was noted for smokers (OR = 1.89, P <.05). Unit (training company) attack rates as high as 8 to 10% per week were documented and the outbreak quickly subsided after live, oral Ad types 4 and 7 vaccination was resumed in November 1997. Re-establishment of a military Ad vaccination program is critical for control of Ad-induced acute respiratory illnesses.

Health assessment of U.S. military personnel deployed to Bosnia-Herzegovina for operation joint endeavor.

In anticipation of U.S. forces deploying to Bosnia-Herzegovina, plans were established to conduct medical surveillance of all military service members. This surveillance would provide the Department of Defense with an overview of the hospitalization and outpatient morbidity experience of U.S. forces. Standardized collection of medical data from all U.S. camps using 14 diagnostic categories based on International Classification of Diseases, 9th Revision, codes began in March 1996. Special assessments for hantavirus and tick-borne encephalitis (TBE) infection risk were also conducted. The average disease and nonbattle injury rate for U.S. forces was 7.1 per 100 soldiers per week. Injuries accounted for 28% of medical visits, whereas undefined/other visits accounted for 33%. The majority of remaining visits were for respiratory (14%), dermatologic (10%), and gastrointestinal (6%) complaints. There was one confirmed and one suspected case of hemorrhagic fever with renal syndrome; only 0.1% of individuals (2 of 1,913) tested seroconverted to hantavirus during deployment. No cases of TBE were reported, and the overall low seroconversion rate (0.42%, 4 seroconversions among 959 unimmunized personnel) reflected a very low risk of infection with TBE-related viruses. Operation Joint Endeavor and follow-on Operations Joint Guard and Joint Forge have been extremely healthy deployments.

Hyponatremia associated with overhydration in U.S. Army trainees.

This report describes a series of hyponatremia hospitalizations associated with heat-related injuries and apparent over-hydration. Data from the U.S. Army Inpatient Data System were used to identify all hospitalizations for hyposmolality/hyponatremia from 1996 and 1997. Admissions were considered as probable cases of overhydration hyponatremia if this was the only, or primary, diagnosis or if it was associated with any heat-related diagnosis. Seventeen medical records were identified, and the events leading to hospitalization were analyzed. The average serum sodium level was 122 +/- 5 mmol/L (range, 115-130 mmol/L). All 17 patients were soldiers attending training schools. Seventy-seven percent of hyponatremia cases occurred in the first 4 weeks of training. Nine patients had water intake rates equal to or exceeding 2 quarts per hour. Most patients were in good health before developing hyponatremia. The most common symptoms were mental status changes (88%), emesis (65%), nausea (53%), and seizures (31%). In 5 of 6 cases in which extensive history was known, soldiers drank excess amounts of water before developing symptoms and as part of field treatment. The authors conclude that hyponatremia resulted from too aggressive fluid replacement practices for soldiers in training status. The fluid replacement policy was revised with consideration given to both climatic heat stress and physical activity levels. Field medical policy should recognize the possibility of overhydration. Specific evacuation criteria should be established for exertional illness.

Attention to detail: injuries at altitude among U.S. Army Military static line parachutists.

Altitude injuries, defined as injuries sustained by military static line parachutists before ground impact, have not been reviewed for 50 years. There are indications that these injuries are increasing at Fort Bragg, North Carolina. Between May 1, 1994, and April 30, 1996, surveillance was conducted for parachute-related injuries and altitude injuries at Fort Bragg. The incidence of all jump-related injuries was 8.1/1,000 aircraft exits. Significant risk factors for injury included being 30 years of age or older (p < 0.001) and being female (p = 0.003). The overall incidence of altitude injuries was noted to be 0.46/1,000 aircraft exits. Risk factors for altitude injury included being 40 years of age or older (p = 0.005) and in the rank of E-1 to E-3 (p = 0.0001). Fifty-four percent of injuries occurred during exiting before complete parachute deployment, and 46% occurred during the opening shock of the parachute. Mechanisms of injury included static line entanglement (33%), riser/suspension-line entanglement (46%), aircraft strikes (21%), unsecured equipment strikes (1%), and opening shock deceleration (1%). The majority of severe altitude injuries are caused by riser/suspension-line entanglement (63%) and involve the knee joint (37%). Although the incidence of altitude injury is quite small, the potential risk for career-threatening and/or life-threatening injury is great. This risk can be reduced by appropriate training and attention to detail.

Rubella outbreak, Fort Bragg, North Carolina, 1995: a clash of two preventive strategies.

An outbreak of rubella occurred among visiting German troops involved in a combined military exercise at Fort Bragg, North Carolina, in April 1995. Public health and military operational concerns centered on the significant contact the German soldiers had had with host battalion dependents and the impact of the outbreak on the exercise. Ten of the 120 German soldiers were found to be nonimmune; six of these soldiers developed clinical rubella. The four nonimmune soldiers who did not develop skin rashes had received serum immune globulin within 12 hours of identification of the index case. The impact of this outbreak on the Fort Bragg community and its military operations, and the methods used to control the outbreak and salvage the military mission, are described.

Military parachuting injuries: a literature review.

This article is a literature review of the aspects of military parachuting related to occupational medicine and focuses on 'conventional' military static line parachuting using a round parachute. The analysis of injuries resulting from military parachuting provide an excellent example of military occupational medicine practice. The techniques of military parachuting are described in order to illustrate the potential mechanisms of injury, and a number of 'classical' parachuting injuries are described. Finally some recommendations are made for the recording of parachute injuries which would assist in the international comparison of injury rates and anatomical distribution.

Parachuting injuries during Operation Royal Dragon, Big Drop III, Fort Bragg, North Carolina, May 15/16, 1996.

On the night of May 15/16, 1996, the largest parachute assault of United States (US) and United Kingdom (UK) airborne forces in 52 years occurred at Fort Bragg, North Carolina. This paper describes the injuries sustained in that operation. A total of 4,754 (US, N = 3,066; UK, N = 1,688) aircraft exits were made, causing a total of 137 (US, N = 73; UK, N = 64) injuries in 117 personnel (US = 68; UK = 49). There were 15 hospital admissions (US = 8; UK = 7; p = 0.37) and no fatalities. The combined exit injury incidence was 24.6 injured soldiers per 1,000 exits. The US exit injury rate was 22 injured per 1,000 aircraft exits and the UK rate was 29 injured soldiers per 1,000 aircraft exits. This difference was not statistically significant (p = 0.25). Lower extremity sprains, strains, and fractures accounted for the majority of injuries in US and UK forces. UK soldiers sustained significantly more of these potentially incapacitating injuries than US troops, 16.1 per 1,000 exits versus 9.1 per 1,000 exits, respectively (chi 2 = 4.07; p = 0.043; relative risk [RR] = 1.70; 95% confidence interval [CI] = 1.01, 2.86). The UK forces sustained significantly more closed head injuries than US forces, 7.1 per 1,000 exits versus 2.3 per 1,000 exits, respectively (chi 2 = 6.4; p = 0.011; RR = 3.13; 95% CI = 1.23, 7.93). The UK forces also had significantly more soldiers with multiple injuries than US forces (RR = 9.15; 95% CI = 2.5, 39.7). Factors that may have influenced differences in injury incidence include differences in weight of personal equipment and possible differences between the drop zones.

An accelerated schedule for tick-borne encephalitis vaccine: the American Military experience in Bosnia.

Tick-borne encephalitis (TBE) is a viral illness endemic to the Balkan region. United States military forces were deployed to Bosnia in early 1996 as part of Operation Joint Endeavor, a U.S.-led multinational peace-keeping operation. To counteract the TBE threat, an inactivated, parenteral vaccine (FSME-Immun Inject; Immuno AG, Vienna, Austria) was offered to soldiers at high risk on a volunteer basis in an accelerated, 3-dose schedule (0, 7, and 28 days). Passive adverse reaction surveillance was conducted on 3,981 vaccinated personnel. Paired sera from a randomly selected group of 1,913 deployed personnel (954 who received vaccine and 959 who were unvaccinated) were tested for antibodies to TBE by an ELISA. Three-dose recipients demonstrated an 80% seroconversion rate (4-fold or greater increase in anti-TBE titers). By comparison, the TBE infection rate in the unvaccinated cohort was found to be only 0.42% (4 of 959). Only 0.18% of vaccinees reported self-limited symptoms. An accelerated immunization schedule appears to be an acceptable option for military personnel or travelers on short-term notice to TBE-endemic areas.

Parachuting injury surveillance, Fort Bragg, North Carolina, May 1993 to December 1994.

Surveillance for parachute-related injuries was conducted at Fort Bragg, North Carolina, between May 1993 and December 1994. During this 20-month period, lower-extremity injuries (27% of all injuries), axial skeletal (back and neck) strains and sprains (19.3%), and closed head injuries (18.4%) were the leading causes of injury. The incidence of injuries requiring emergency care was 8/1,000 jumps. This rate is well within the jump injury planning estimate, suggesting that airborne training and operations are conducted in a safe and effective manner at Fort Bragg.

The life of Brigadier General Theodore C. Lyster.

Theodore C. Lyster is a familiar name to aerospace medicine physicians. His early recognition of the unique physical requirements of aviators, the specialized training necessary for flight surgeons, and the need for altitude physiology research provided the foundation on which the specialty of aviation medicine was built. Lyster's medical career, however, encompassed much more than aviation medicine. From his earliest assignment as a contract physician in Cuba in 1899 until his entry into private practice in 1921, he was heavily involved with the fight against yellow fever. In the era before medical residencies were commonplace, Lyster sought out training in ophthalmology and otolaryngology in the U.S. and abroad. His clinical and organizational abilities made him a valuable asset during the construction of the Panama Canal and during World War I. Lyster's many talents and his philosophy about aviation medicine make him a worthy role model for flight surgeons today.

Safety and immunogenicity of the oral, whole cell/recombinant B subunit cholera vaccine in North American volunteers.

A newly formulated, oral, inactivated whole cell plus recombinant B subunit (WC/rBS) cholera vaccine was evaluated in US military personnel. In the first study, 74 subjects were given two doses 14 days apart. In the second study, 186 subjects were randomized into four groups; two groups received vaccine with either full (4 g) or half (2 g) strength bicarbonate buffer, and two groups received either full or half strength buffer without vaccine. Mild gastrointestinal symptoms were associated with full buffer (P = .02) but not with the vaccine. In the first study, 36% of all subjects and 55% with low prevaccination titers (< 1:40) had a > or = 2-fold rise in vibriocidal antibody level; > 80% of subjects developed a 4-fold rise in anti-cholera toxin (CT) titers. Post-vaccination IgA and IgG anti-CT titers were approximately 1.5-fold higher among persons receiving full strength buffer (P = .05). The WC/rBS vaccine is safe and immunogenic in North Americans, although some mild gastrointestinal symptoms occur with the high concentration of buffer necessary to protect the B subunit from gastric acid denaturation. Prior immunity to cholera conferred by parenteral vaccine decreased vibriocidal antibody response.