Military immunizations. Past, present, and future prospects.

The United States military immunizes its forces against a variety of infectious diseases of military importance. Military vaccines can be divided into several categories: (1) routinely administered vaccines for recruits and the total force; (2) deployment-specific vaccines, (3) occupational vaccines based on specific job-associated risks, and (4) experimental limited use vaccines for special contingency situations. New vaccines based on new technological advances are being developed to meet the continuous requirements of the military.

Rapid serodiagnosis of leptospirosis using the IgM-specific Dot-ELISA: comparison with the microscopic agglutination test.

The dot enzyme-linked immunosorbent assay (Dot-ELISA) was compared to the microscopic agglutination test (MA test) for the diagnosis of human leptospirosis. Of 177 sera from 68 soldiers who trained in the Republic of Panama, 102 sera were positive in the MA test and 93 of these sera were positive in the IgM-specific Dot-ELISA. Incidence of infection was 50 of 68 patients with the MA test and 48 of 68 in the IgM Dot-ELISA. Five MA test-positive sera were reactive only in the IgG-specific Dot-ELISA, suggesting previous exposure. All 21 infecting serovars of Leptospira interrogans, as determined by positive reactions in the MA test or culture of blood and urine specimens, were reactive in the Dot-ELISA. Of 75 sera negative in the MA test, 61 were nonreactive in the Dot-ELISA. However, 9 of these 14 Dot-ELISA-positive/MA test-negative sera were acute samples from patients whose later sera were MA test-positive. Positive reactions in the IgM Dot-ELISA occurred in 2 of 30 control, 4 of 10 Lyme disease, 1 of 11 relapsing fever, and 1 of 8 yaws sera; 10 syphilis patient sera were nonreactive. The IgM-specific Dot-ELISA appears to be sensitive and specific for the serodiagnosis of acute leptospirosis. In addition, this rapid test is inexpensive, simple to perform, utilizes minute volumes of killed leptospiral antigen and is easily adaptable to field use.

Cutaneous leishmaniasis associated with jungle training.

In November 1977, 627 soldiers belonging primarily to the First Battalion, 82nd Airborne Division, stationed at Fort Bragg, were sent to the Canal Zone, Panama, for jungle warfare training. A medical surveillance program incorporating pre- and post-evaluations over a 6-month period with dermatologic examinations, questionnaires, and serologic tests was established. Ten cases of cutaneous leishmaniasis (1.6/100 men) were diagnosed by positive Leishmania culture. The demonstrated lack of sensitivity and specificity of the indirect fluorescent antibody test and the direct agglutination test render these serological methods useless as diagnostic screening methods in the early stages of this disease.

American cutaneous leishmaniasis: a comparison of three sodium stibogluconate treatment schedules.

Thirty-six patients with American cutaneous leishmaniasis were randomized to receive intravenous sodium stibogluconate for 10 days at a dose of 600 mg antimony (Sb) per day by one of three schedules: once daily by rapid infusion (A), by continuous 24 hr infusion (B), or in divided doses every eight hours by rapid infusion (C). Patients not cured after initial treatment were rerandomized to one of the other treatment schedules. An additional 19 patients who were not part of the randomized study received standard (STD) sodium stibogluconate treatment (600 mg Sb once daily by rapid infusion for 10 days, identical with schedule A). In the randomized study, the overall cure rate after the first course of treatment was 64%, but was higher for schedule A (100%) than for B (50%) or C (42%) (P less than 0.01). Considering all courses of treatment, schedule A was more effective (94%) than B (53%) or C (43%) (P less than 0.01). Paradoxically, patients in group A had a higher cure rate than patients in group STD (42% after the first course of treatment and 51% when all courses of treatment were considered). Side effects were mild and well tolerated. Total side effects were more frequent in groups B + C (52%) than A + STD (23%) due to an increased incidence of subjective complaints (26% vs. 10%, P less than 0.05) in patients receiving other than once daily rapid infusion. We conclude that giving the same total amount of sodium stibogluconate in three divided doses or by continuous infusion offers no advantage over standard, once daily treatment of American cutaneous leishmaniasis.

An outbreak of hookworm infection associated with military operations in Grenada.

During 1983, a multinational military intervention took place on Grenada. After deployment, troops from several U.S. Army units noted signs and symptoms consistent with soil-transmitted helminthic infection. Of 684 soldiers screened five to seven weeks post-deployment, over 20% reported abdominal pain and/or diarrhea during or after the action. Eosinophilia of at least 10% was observed in 119 (22.5%) of 529 soldiers evaluated further; eosinophilia of 5-9% was documented in another 126 (23.8%) of the 529 soldiers. Stool examinations confirmed hookworm infection in 35 soldiers. One case of strongyloidiasis was also documented. Infection was attributed to ground exposure near homes with compromised sanitation. Units that joined the operation after the initial assault phase were at low risk of hookworm infection.

Circumcision as a risk factor for urethritis in racial groups.

A retrospective population-based case-control study of sexually transmitted urethritis was conducted at a large military base over a 21-month period. During the study, 9,514 patients were seen for sexually transmitted disease. The analysis was restricted to active duty males and showed that Blacks had 14.8 times the incidence rate of gonococcal urethritis (GCU) and 4.7 times the rate of nongonococcal urethritis (NGU) compared to Whites. There were slightly fewer cases of NGU than GCU. A case-control study of active duty soldiers showed that both Black and White circumcised subjects were 1.65 times as likely to have NGU as uncircumcised subjects (95% CI: 1.37-2.00). However, circumcision was not associated with an increased incidence of GCU.

The military and hepatitis B.

Hepatitis B virus (HBV) is an important cause of morbidity in military forces. HBV threatens a safe blood supply for mass casualties, contributes to rising health care costs and presents an occupational risk to health care workers. The susceptibility of soldiers reflects that of other residents of their country of origin. In intermediate and high-prevalence regions, infections usually occur in young adults and follow exposure to an HBV carrier through blood or sexual contact. Control of HBV infections must rely on education regarding risk factors, screening of blood donors and immunization. Military populations provide unique opportunities for studying the epidemiology of hepatitis B and carrying out mass vaccination programmes.

Simultaneous administration of live, enteric-coated adenovirus types 4, 7 and 21 vaccines: safety and immunogenicity.

The safety of and the immune response to simultaneous administration of live, enteric-coated adenovirus type 4 (ADV-4), type 7 (ADV-7), and type 21 (ADV-21) vaccines were studied. Volunteers (476 men), randomly assigned to four study groups, received three vaccines (ADV-4, ADV-7, and ADV-21), two vaccines (ADV-4 and ADV-7), one vaccine (ADV-21), or no vaccine (placebo). Subjects were observed for three weeks, and no side effects due to vaccination occured. The percentages of susceptible subjects (those entering the study with a neutralizing antibody titer of less than 1:2 to each vaccine virus received) who seroconverted to ADV-4 were similar in both groups that received ADV-4 vaccine (78% of 77 subjects and 74% of 76). However, in the group that received three vaccines, only 62% of 77 subjects seroconverted to ADV-7, compared with 79% of 76 in the group that received two vaccines (P less than 0.05). Only 58% of 77 subjects in the three-vaccine group seroconverted to ADV-21, compared with 69% of 59 in the group that received one vaccine (P greater than 0.1).

A military community outbreak of hepatitis type A related to transmission in a child care facility.

An outbreak of hepatitis type A occurred among military personnel and dependents on a military post in Anchorage, Alaska, August 1976-April 1977. One hundred sixteen clinical cases of hepatitis were identified over a nine-month-period. Ninety-six per cent of those cases that were tested demonstrated IgM antibody to hepatitis A virus. A large child care facility was implicated as a major focus of hepatitis virus transmission. Sixty-four (55%) of the cases were directly or indirectly linked to the child care facility. The length of time that a child spent at the facility appeared to increase the child's risk of developing hepatitis and the risk of his transmitting the hepatitis A virus to other members of the immediate household.

Effect of spectinomycin use on the prevalence of spectinomycin-resistant and of penicillinase-producing Neisseria gonorrhoeae.

Because of the high prevalence of penicillinase-producing Neisseria gonorrhoeae in the Republic of Korea, spectinomycin has been used there in the primary treatment of gonococcal infections in U.S. military personnel since 1981, but there have been increasingly frequent reports of treatment failures with spectinomycin. We conducted a clinical study to determine the efficacy of spectinomycin treatment in 124 U.S. servicemen in the Republic of Korea who had urethral gonococcal infections. Ninety-seven patients were treated with spectinomycin alone and evaluated in a follow-up visit. In eight patients (8.2 percent), this treatment was unsuccessful. Antibiotic-sensitivity testing on isolates from seven of the patients with treatment failure demonstrated that six isolates were highly resistant to spectinomycin (minimal inhibitory concentration, greater than or equal to 100 micrograms per milliliter). None of the spectinomycin-resistant strains had become resistant to penicillin, either through the production of penicillinase or through a chromosomal mutation. Although the mechanism of spectinomycin resistance appears to be a chromosomal mutation, these isolates were generally sensitive to other antibiotics. The prevalence of resistance to spectinomycin resulted in the substitution of ceftriaxone for the primary treatment of gonorrhea acquired by U.S. military personnel in the Republic of Korea. We believe that the rapid emergence of spectinomycin resistance in this population mandates a cautious approach to widescale use of the drug and indicates a need to broaden current surveillance programs.

An efficacy trial of doxycycline chemoprophylaxis against leptospirosis.

Because leptospirosis has been an important cause of morbidity in U.S. soldiers training in the Republic of Panama, we conducted a randomized, double-blind, placebo-controlled field trial during the fall of 1982 to determine whether doxycycline was an effective chemoprophylactic agent against this infection. Doxycycline (200 mg) or placebo was administered orally on a weekly basis and at the completion of training to 940 volunteers from two U.S. Army units deployed in Panama for approximately three weeks of jungle training. Twenty cases of leptospirosis occurred in the placebo group (an attack rate of 4.2 per cent), as compared with only one case in the doxycycline group (attack rate, 0.2 per cent, P less than 0.001), yielding an efficacy of 95.0 per cent. This study demonstrated the value of doxycycline as a prophylactic drug against leptospirosis.