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Biomedical subjects

K C Hyams

Publications and source records attributed to K C Hyams.

At least 73 records · Page 4Linked to original sources
PubMed1994

Diarrheal disease aboard a U.S. Navy ship after a brief port visit to a high risk area.

In August 1988, a study was conducted to determine the etiology and risk factors associated with travelers' diarrhea among U.S. military personnel after a 5-day port visit to Alexandria, Egypt. Twenty-one percent of the 2,747 evaluated crew members of the USS John F. Kennedy reported an episode of acute diarrhea, which led to 155 sick-call visits and at least 110 lost man-days. The most common pathogen identified was enterotoxigenic Escherichia coli, and all isolated bacterial enteropathogens were sensitive to quinolone drugs. Independent risk factors for the development of diarrhea included: (1) consuming any meal ashore and specifically eating meats, desserts, or a buffet meal; and (2) a recent history of travelers' diarrhea. These data indicate that even brief port visits to developing countries pose a major threat to the health of U.S. shipboard personnel.

Acute Disease↗
PubMed1993

Tuberculosis infection among young adults entering the US Navy in 1990.

BACKGROUND: From 1958 through 1969, more than 1.2 million US Navy recruits received tuberculin skin tests; 5.2 per 100 were tuberculin reactors. Subsequent analyses predicted a downward trend in the risk of tuberculosis infection in the United States. We sought to determine the current prevalence of tuberculin reactors by sex, race/ethnic group, and birthplace among young adult residents of the United States entering the US Navy. METHODS: Recruits routinely receive a tuberculin skin test on entering US Navy recruit training in Great Lakes, Ill, Orlando, Fla, or San Diego, Calif. In January and February 1990, 2416 young men and women (mean age, 20.6 years) received tuberculin skin tests and completed questionnaires eliciting demographic and tuberculosis risk factor data. A tuberculin reactor was defined as a subject having 10 mm or greater induration to a skin test with 5 tuberculin units, purified protein derivative, administered intradermally by the Mantoux method. RESULTS: Fifty-five of 2214 men (2.5 per 100; 95% confidence interval, 1.9 to 3.2 per 100) and five of 202 women (2.5 per 100; 95% confidence interval, 0.8 to 5.8 per 100) were tuberculin reactors. For men, the prevalence was greater in blacks (5.2 per 100), Hispanics (5.4 per 100), and Asian/Pacific Islanders (26.4 per 100) than in whites (0.8 per 100) and greater in foreign-born recruits (19.2 per 100) than in recruits born in the United States (1.6 per 100). Women had the same pattern of prevalence by race/ethnic group and birthplace. CONCLUSIONS: The prevalence of tuberculosis reactors declined as predicted among young adults, especially the white US-born recruits, entering the US Navy. Although the prevalence also declined among nonwhites and the foreign-born recruits, a substantial proportion continue to enter adulthood with preexisting tuberculosis infection.

Adult↗
PubMed1993

Second generation hepatitis C virus assays: performance when testing African sera.

Sera were collected from 426 volunteers in Uganda at high and low risk for acquisition of hepatitis C virus (HCV). All samples were tested by the Ortho HCV second generation ELISA (S1) and by the INNOTEST HCV Ab second generation enzyme immunoassay, (S2), (Innogenetics, Antwerpen, Belgium). Sera that were repeatedly reactive by either screening assay were further tested by each of two different HCV supplemental/confirmatory assays: a second generation recombinant immunoblot assay (RIBA, Ortho Diagnostics), (C1), and a line immunoassay (INNO-LIA HCV-Ab, Innogenetics), (C2). In these populations there were 16 true positives, 351 true negatives, and 59 indeterminate results. Fifty-nine point four percent (253/426) of the samples were repeatedly reactive by the S1 test, while only 2.6% (11/426) were repeatedly reactive by S2. Test S1 produced a high false positive rate, a low positive predictive value, a specificity of 49.3%, and had a sensitivity of 100%. In contrast, the S2 screening assay had much higher specificity (98.8%), but lacked in sensitivity (31.3%). This poor sensitivity of S2 was based almost exclusively on the fact that the C2 supplemental test classified 9 samples as confirmed positive when the homologous screening assay classified these samples as negative; several of these were not confirmed when using a new generation INNO-LIA. Both the screening tests S1 and S2, and the supplemental assays C1 and C2 exhibited a significant degree of discordance, and neither of the screening tests alone would be adequate for use in these populations.

Adult↗
PubMed1993

Ciprofloxacin versus ceftriaxone in the treatment of multiresistant typhoid fever.

A randomized trial comparing ceftriaxone (3 g given parenterally per day for 7 days) to ciprofloxacin (500 mg given orally twice a day for 7 days) in the treatment of blood culture positive typhoid fever was conducted. Twenty patients were openly randomized to receive ciprofloxacin and 22 to receive ceftriaxone. The outcome was classified as clinical failure in 6 patients (27%) in the ceftriaxone group, but in none in the ciprofloxacin group (p = 0.01). The mean duration of fever was four days in the ciprofloxacin group and about five days in the ceftriaxone group (p = 0.04). In the six patients in the ceftriaxone group who experienced failure, therapy was switched to ciprofloxacin and the patients became afebrile and asymptomatic within 48 hours. Patients with resistant strains of Salmonella typhi and patients with sensitive strains responded equally well to ciprofloxacin therapy. Analysis of a subset of 12 of the multiresistant strains revealed that resistance was encoded for by a transferable 180 kilobase plasmid. Ciprofloxacin represents a useful treatment option in areas where multiresistant strains are likely to be encountered.

Bacteriophage Typing↗
PubMed1993

Interpreting a single antistreptolysin O test: a comparison of the "upper limit of normal" and likelihood ratio methods.

Single serologic tests may occasionally influence clinicians in making diagnoses. The antistreptolysin O (ASO) test is a frequently used tool for detecting recent Streptococcus pyogenes infection and is helpful in the diagnosis of diseases like rheumatic fever. Using data from a 1989 prospective study of 600 healthy male military recruits, in which 43% experienced S. pyogenes upper respiratory tract infection (2-dilution rise in ASO), this report compared two methods of interpreting a single ASO titer. Using the "upper limit of normal" (80 percentile) method, recruits with an ASO titer of greater than 400 showed evidence of recent S. pyogenes infection. This method had a sensitivity and specificity of only 65.9 and 81.9% respectively. In contrast to the "yes-no" dichotomy of the "upper limit of normal" method, the likelihood ratio method statistics were ASO value specific, more consistent with clinical judgment, and better emphasized the caution clinicians must use in interpreting a single ASO test.

Antistreptolysin↗
PubMed1993

Evaluation of five hepatitis C virus screening tests and two supplemental assays: performance when testing sera from sexually transmitted diseases clinic attendees in the USA.

The performances of five screening tests (recombinant peptide-based first and second generation tests from Abbott and Ortho, and a synthetic peptide-based test from Biochem Immunosystems) and two supplemental tests: recombinant peptide- based, Abbott neutralization test and Chiron second generation recombinant immunoblot assay (RIBA 2), were evaluated for their ability to detect hepatitis C virus (HCV) antibodies in a population of 276 individuals attending a sexually transmitted diseases (STD) clinic in the USA. Although the five screening tests produced a variable number (35-62) of repeatedly reactive samples, only 13% (36/276) were classified as true positives by the supplemental tests. Thirty-four of the 36 were reactive by all screening tests and 32 of the true positives were reactive by both supplemental tests, while 2 did not neutralize but were reactive in the RIBA 2 test. Of the remaining 2 of the true positives which were discordant by several of the screening assays, 1 was confirmed by both supplemental assays but the other required a chemiluminescent enhancement technique to show positivity in RIBA 2. The sensitivities of the first and second generation Abbott and Ortho tests ranged from 97% to 100% and that of the Biochem test was 94%. The specificities of these tests ranged from 89.2% to 99.6%. The second generation Ortho test presented 9.4% (26/276) false positives. The use of second generation Ortho as a screening test would lead to an excessive number of confirmatory false positives. the positive predictive values of the screening tests ranged from 58.1% to 97.1%. Although the synthetic peptide based Biochem test exhibited the best overall indices, the presence of 2 false negative results would prevent its use as a singular screening test. Nevertheless its high specificity may lend itself to be used as a second screening test before confirmatory testing with RIBA 2.

Journal Article↗
PubMed1993

Characterization of enterotoxigenic Escherichia coli isolated from U.S. troops deployed to the Middle East.

Enterotoxigenic Escherichia coli (ETEC) was a common cause of traveler's diarrhea in U.S. soldiers in the Middle East in 1989 and 1990. To determine which bacterial components would be useful in a vaccine, potential protective antigens (toxin, colonization factor antigen [CFA], and serotype) from 189 ETEC isolates were examined. Nearly half of the isolates expressed both ETEC toxins, 39% had only heat-stable enterotoxin (ST), and 17% had heat-labile enterotoxin (LT). CFA/I was the least common colonization factor antigen (11%), CFA/II was common (34%), as was CFA/IV (31%), and 24% expressed none of these CFAs. Fifty-seven O:H serotypes were found. Serotype O6:H16 was the most common, occurring in 29% of the ETEC isolates, usually with LT-ST and CFA/II. Generally, CFA/II was associated with expression of both toxins, CFA/IV was associated with expression of ST, and none of the CFAs was routinely found with LT. We conclude that ETEC from soldiers in the Middle East expressed a variety of antigens and that an effective vaccine will require multiple protective antigens.

Antigens, Bacterial↗
PubMed1993

The risk of measles, mumps, and varicella among young adults: a serosurvey of US Navy and Marine Corps recruits.

OBJECTIVES: To assess the risk of epidemic transmission and to guide immunization policy, the seroprevalence of antibody to measles, mumps, and varicella was determined in a group of young adults. METHODS: A cross-sectional study of 1533 US Navy and Marine Corps recruits was conducted in June 1989. Antibody status was determined with commercially available enzyme-linked immunosorbent assays. RESULTS: Direct sex and race adjustment to the 15- to 29-year-old US population resulted in seronegativity rates of 17.8% for measles, 12.3% for mumps, and 6.7% for varicella. Measles and mumps seronegativity rates were higher among Whites whereas varicella seronegativity was higher among non-Whites. Recruits enlisting from outside the 50 US states, especially those from island territories, were more likely to lack varicella antibody. The sensitivity of a positive history of vaccination or disease in predicting antibody status was less than 90% for all diseases. CONCLUSIONS: These results suggest a continued potential for epidemics, especially of measles, and the need for mandatory immunization policies. Immigrants to the United States, especially those from island territories, may be a high-risk group that could benefit from varicella vaccination.

Adolescent↗
PubMed1993

Respiratory disease among military personnel in Saudi Arabia during Operation Desert Shield.

OBJECTIVES: The purpose of this study was to determine whether respiratory disease due to crowded living conditions and high levels of suspended and blowing sand had a major adverse impact on US military personnel during Operation Desert Shield. METHODS: A questionnaire survey was administered to 2598 combat troops stationed in Northeast Saudi Arabia for a mean of 102 days. Samples of surface sand from seven different locations were analyzed by scanning electron microscopy and x-ray diffraction. RESULTS: Among surveyed troops, 34.4% reported a sore throat, 43.1% complained of a cough, 15.4% complained of chronic rhinorrhea, and 1.8% were unable to perform their routine duties because of upper respiratory symptoms. Evaluation of sleeping accommodations indicated that complaints of a sore throat and cough were most closely associated with sleeping in air-conditioned buildings; in contrast, complaints of rhinorrhea were associated with exposure to the outdoor environment while living in tents. Sand samples consisted mostly of quartz, with just 0.21% by weight of respirable size (< 10 microns in diameter). CONCLUSIONS: These findings indicate that upper respiratory complaints were frequent among Operation Desert Shield troops and were related both to the troops' housing and to their exposure to the outside environment.

Adolescent↗
PubMed1993

Diarrheal and respiratory disease aboard the hospital ship, USNS-Mercy T-AH 19, during Operation Desert Shield.

Diarrhea and respiratory disease were common problems among ground troops deployed to the Middle East during Operation Desert Shield. In order to determine the prevalence and impact of diarrheal and upper respiratory disease among shipboard personnel during this period, an epidemiologic survey was conducted on the hospital ship, USNS Mercy T-AH 19. An episode of acute diarrhea was reported by 46% of the surveyed population, and 79% reported upper respiratory symptoms. Six percent of personnel were temporarily unable to perform scheduled duties due to gastrointestinal symptoms and 7% due to respiratory symptoms. Officers were at increased risk of experiencing an episode of diarrhea, and female crew members more often reported respiratory complaints. Improved strategies to prevent diarrhea and respiratory disease among shipboard personnel are needed.

Adolescent↗
PubMed1993

Etiology of acute diarrhea among United States military personnel deployed to South America and west Africa.

A study of acute diarrhea was conducted from 1985 to 1987 among U.S. military personnel participating in routine shipboard exercises in South America and West Africa and ground troops deployed to coastal Ecuador. An enteropathogen was identified in 146 (51%) of 289 acute cases of diarrhea. Enterotoxigenic Escherichia coli, found in 50 (17%) patients with diarrhea, was the most commonly identified enteropathogen. Viral enteropathogens were also found in a high percentage of acute cases of diarrhea: rotavirus was detected in 11% of the patients and Norwalk virus infection in 10%. Most enteric pathogens were acquired in equal frequencies in South America and West Africa, except for rotavirus infection which was identified more often in West Africa and enteroaggregative E. coli infection which was identified more often in South America. Bacterial enteropathogens were frequently resistant to trimethoprim/sulfamethoxazole, but no resistance to quinolone drugs was observed, indicating that quinolone drugs have become important agents for the treatment of diarrhea in South America and West Africa.

Acute Disease↗
PubMed1993

Acute sporadic hepatitis E in an Egyptian pediatric population.

A study was conducted to determine the etiology of acute hepatitis among 261 children (age range 1-11 years) living in Cairo, Egypt. A blood sample was obtained from each subject when initially evaluated and a questionnaire was used to collect demographic and risk factor data. Sera were tested by enzyme immunoassay for acute hepatitis A (anti-hepatitis A virus IgM), hepatitis B (anti-hepatitis B core antigen IgM and hepatitis B surface antigen [HBsAg]), hepatitis C (total anti-HCV), delta hepatitis (total anti-delta), and cytomegalovirus infection (anti-CMV IgM). In addition, hepatitis E virus (HEV) infection was diagnosed using a new Western blot technique to test patients with non-A, non-B hepatitis for anti-HEV IgM. Among 261 children, acute hepatitis A was diagnosed in 85 (32.6%) patients, acute hepatitis B in 19 (7.3%), delta hepatitis in 3 (1.1%), mixed hepatitis A and B infection in 2 (0.8%), CMV infection in 1 (0.4%), hepatitis E in 58 (22.2%), and non-A, non-B hepatitis of unknown type in 51 (19.5%). Forty-two (16.1%) subjects had HBsAg without other markers of acute infection. Risk factor analysis indicated that patients living in homes not connected to a municipal source of water were at increased risk of hepatitis E infection. These data provide additional evidence that hepatitis E virus is a common cause of acute sporadic hepatitis in children living in Egypt.

Acute Disease↗
PubMed1993

Three-year incidence study of retroviral and viral hepatitis transmission in a Peruvian prostitute population.

A Peruvian female prostitute population was evaluated over a 3-year period to determine the incidence and risk factors of retroviral and viral hepatitis transmission. At three survey periods, a questionnaire was administered and serum samples were obtained. A total of 966 subjects were studied, with 34% followed for 38 months, 22% followed for 18 months, and 44% evaluated just once. On initial evaluation, 3 (0.3%) had HIV-1 antibody, 170 (17.6%) had HTLV-I antibody, 578 (59.8%) had anti-HBc, and 7 (0.7%) had antibody to hepatitis C virus. The mean annual incidence of HTLV-I and hepatitis B infection was 1.6% and 4.7%, respectively. Univariate and logistic regression analysis of prevalence data indicated an association between sexual activity and HTLV-I and hepatitis B infection, but no independent risk factors were identified in cohort analysis. Parenteral risk factors were not associated with transmission, except for a small percentage of subjects who may have acquired hepatitis B infection from blood transfusions. These findings suggest that there is a high incidence of HTLV-I and hepatitis B infection from heterosexual contact in this female prostitute population.

Adult↗
PubMed1993

Leishmaniasis among Desert Storm veterans: a diagnostic and therapeutic dilemma.

Troops stationed in the Middle East during Operations Desert Shield/Storm were potentially exposed to leishmaniasis, a parasitic infection transmitted by sandflies. In this region, infection primarily causes cutaneous and, less often, visceral disease. Visceral leishmaniasis, which typically has an incubation period of several months, can be a difficult diagnosis as it presents with a wide range of symptoms and there are no non-invasive, reliable diagnostic tests. Cutaneous leishmaniasis is more easily diagnosed using culture and stained smears of biopsy and aspirate samples from skin lesions. Pentavalent antimonials are most often used to treat leishmaniasis; however, treatment is potentially toxic and not recommended except in cases of documented disease.

Humans↗
PubMed1993

The Navy Forward Laboratory during Operations Desert Shield/Desert Storm.

The Navy Forward Laboratory (NFL) was an advanced infectious disease laboratory which provided a theater-wide reference diagnostic capability during Operations Desert Shield/Storm. During Operation Desert Shield, when massive numbers of troops were being deployed, the NFL primarily supported medical personnel in the diagnosis and treatment of infectious diseases. During the war, the laboratory provided rapid biologic warfare diagnostic support. The NFL demonstrated the benefits of a comprehensive, on-site diagnostic laboratory when large numbers of troops are deployed to high-risk areas and demonstrated the importance of military medical research laboratories for training of scientists and physicians, threat assessment, and product development.

Humans↗