Unusually high illness severity and short incubation periods in two foodborne outbreaks of Salmonella Heidelberg infections with potential coincident Staphylococcus aureus intoxication.

We describe the investigation of two temporally coincident illness clusters involving salmonella and Staphylococcus aureus in two states. Cases were defined as gastrointestinal illness following two meal events. Investigators interviewed ill persons. Stool, food and environmental samples underwent pathogen testing. Alabama: Eighty cases were identified. Median time from meal to illness was 5·8 h. Salmonella Heidelberg was identified from 27 of 28 stool specimens tested, and coagulase-positive S. aureus was isolated from three of 16 ill persons. Environmental investigation indicated that food handling deficiencies occurred. Colorado: Seven cases were identified. Median time from meal to illness was 4·5 h. Five persons were hospitalised, four of whom were admitted to the intensive care unit. Salmonella Heidelberg was identified in six of seven stool specimens and coagulase-positive S. aureus in three of six tested. No single food item was implicated in either outbreak. These two outbreaks were linked to infection with Salmonella Heidelberg, but additional factors, such as dual aetiology that included S. aureus or the dose of salmonella ingested may have contributed to the short incubation periods and high illness severity. The outbreaks underscore the importance of measures to prevent foodborne illness through appropriate washing, handling, preparation and storage of food.

First Report of "Candidatus Liberibacter solanacearum" on Field Tomatoes in the United States.

In August 2008, 30% of tomato (Solanum lycopersicum) plants in plots in Lubbock County, Texas showed yellowing, lateral stem dieback, upward leaf curling, enlargement of stems, adventitious roots, and swollen nodes. Yellowing in leaves was similar to that seen with zebra chip disease (ZC) of potato that was confirmed in a potato field 112 km away in July 2008 and was associated with a 'Candidatus Liberibacter' species (1), similar to findings earlier in 2008 in New Zealand and California (2,3). Tissue from four symptomatic plants of cv. Spitfire and two of cv. Celebrity were collected and DNA was extracted from midribs and petioles with a FastDNA Spin Kit (Qbiogene, Inc., Carlsbad, CA,). PCR amplification was done with 16S rRNA gene primers OA2 and OI2c, which are specific for "Ca. Liberibacter solanacearum" from potato and tomato and amplify a 1.1-kb fragment of the 16S rRNA gene of this new species (1,3). Amplicons of 1.1 kb were obtained from all samples and these were sequenced in both orientations (McLab, San Francisco, CA). Sequences of the 16S rRNA gene were identical for both Spitfire and Celebrity and were submitted to the NCBI as GenBank Accession Nos. FJ939136 and FJ939137, respectively. On the basis of a BLAST search, sequence alignments revealed 99.9% identity with a new species of 'Ca. Liberibacter' from potato (EU884128 and EU884129) in Texas (1); 99.7% identity with the new species "Ca. Liberibacter solanacearum" described from potato and tomato (3) in New Zealand (EU849020 and EU834130, respectively) and from the potato psyllid Bactericera cockerelli in California (2) (EU812559, EU812556); 97% identity with 'Ca L. asiaticus' from citrus in Malaysia (EU224393) and 94% identity with both 'Ca. L. africanus' and 'Ca. L. americanus' from citrus (EU921620 and AY742824, respectively). A neighbor-joining cladogram constructed using the 16S rRNA gene fragments delineated four clusters corresponding to each species, and these sequences clustered with "Ca. L. solanacearum". A second PCR analysis was conducted with the CL514F/CL514R primer pair, which amplifies a sequence from the rplJ and rplL ribosomal protein genes of "Ca. L. solanacearum". The resulting 669-bp products were 100% identical to a sequence reported from tomato in Mexico (FJ498807). This sequence was submitted to NCBI (GU169328). ZC, a disease causing losses to the potato industry, is associated with a 'Candidatus Liberibacter' species (1-3) and was reported in Central America and Mexico in the 1990s, in Texas in 2000, and more recently in other states in the United States (4). In 2008, a "Ca. Liberibacter solanacearum" was detected on Capsicum annuum, S. betaceum, and Physalis peruviana in New Zealand (3). Several studies have shown that the potato psyllid, B. cockerelli, is a potential vector for this pathogen (2,4). To our knowledge, this is the first report of "Ca. Liberibacter solanacearum" in field tomatoes showing ZC-like foliar disease symptoms in the United States. References: (1). J. A. Abad et al. Plant Dis. 93:108, 2009 (2) A. K. Hansen et al. Appl. Environ. Microbiol. 74:5862, 2008. (3) L. W. Liefting et al. Plant Dis. 93:208, 2009. (4) G. A. Secor et al. Plant Dis. 93:574, 2009.

Condom use in the year following a sexually transmitted disease clinic visit.

Consistent condom use can prevent sexually transmitted infections (STIs), but few studies have measured how the prevalence of consistent use changes over time. We measured the prevalence and correlates of consistent condom use over the course of a year. We did a secondary analysis of data from an HIV prevention trial in three sexually transmitted disease clinics. We assessed condom use during four three-month intervals for subjects and across their partnerships using unconditional logistic regression. Condom use was also assessed for subjects during all three-month intervals combined. The 2125 subjects reported on 5364 three-month intervals including 7249 partnership intervals. Condoms were always used by 24.1% of subjects and 33.2% of partnerships during a three-month interval. Over the year, 82% used condoms at least once but only 5.1% always used condoms. Always use of condom was more likely for subjects who had sex only once (66.5%) compared with >30 times (6.4%); one-time partnerships (64.1%) compared with main partnerships (22.2%); and in new partnerships (44.0%) compared with partnerships that were not new (24.5%). Although consistent condom use may prevent STIs, condoms were rarely used consistently during the year of follow-up.

Disseminated meningococcal infection in HIV-seropositive patients.

OBJECTIVE: Although increasing numbers of infections due to various bacterial pathogens have been described in HIV-infected individuals, there have been few reports to date of disseminated Neisseria meningitidis infections in such individuals. We describe here the presentation and clinical course of systemic meningococcal infection in two HIV-1-seropositive men and the response to meningococcal vaccine in one. DESIGN AND METHODS: Retrospective analysis of case reports of two patients identified in a municipal hospital in Denver, Colorado, USA, and evaluation by enzyme-linked immunosorbent assay of antibody response to quadrivalent (A, C, Y, W-135) meningococcal vaccine. RESULTS: A 27-year-old HIV-seropositive man with bacteremic group Y meningococcal pneumonia and a 45-year-old man with AIDS and group B meningococcal arthritis both responded to short-term antibiotic therapy without recurrence. The second patient responded to meningococcal vaccination with seroconversion to all four serogroups. CONCLUSIONS: Disseminated meningococcal infection, although rare in HIV-infected individuals, may present with a variety of clinical manifestations and responds well to antibiotic therapy. Meningococcal vaccine appears to be immunogenic in such individuals.

Readiness of high-risk populations in the HIV Network for Prevention Trials to participate in HIV vaccine efficacy trials in the United States.

OBJECTIVE: To determine the willingness of populations at high risk of HIV-1 infection to participate in HIV vaccine efficacy trials, determine factors influencing decision-making, and evaluate knowledge levels of vaccine trial concepts. DESIGN: Cross-sectional study. METHODS: HIV-1-negative homosexual men, male and female injecting drug users and non-injecting women at heterosexual risk were recruited in eight cities in the United States (n=4892). RESULTS: A substantial proportion of the study population (77%) would definitely (27%) or probably (50%) be willing to participate in a randomized vaccine efficacy trial. Increased willingness was associated with high-risk behaviors, lower education level, being uninsured or covered by public insurance, and not having been in a previous vaccine preparedness study. Altruism and a desire for protection from the vaccine were major motivators for participation. Major concerns included positive HIV-1 antibody test due to vaccine, safety of the vaccine, and possible problems with insurance or foreign travel. Baseline knowledge of vaccine trial concepts was low. CONCLUSIONS: It is likely that high-risk volunteers will be willing to enroll in HIV vaccine efficacy trials. A variety of participant and community educational strategies are needed to address participant concerns, and to ensure understanding of key concepts prior to giving consent for participation.

Multicenter trial of fleroxacin versus ceftriaxone in the treatment of uncomplicated gonorrhea.

In a multicenter, randomized, open, comparative trial, patients with uncomplicated gonorrhea were treated with 400 mg of oral fleroxacin or 250 mg of intramuscular ceftriaxone. A total of 458 men and 447 women were enrolled. Of these, 312 men (68%) and 245 women (55%) were evaluable for efficacy. The treatment groups were demographically similar. Among evaluable men, fleroxacin eradicated 154 of 155 (99%; 95% confidence interval [CI]: 98.1-100%) urethral and 2 of 2 pharyngeal infections, while ceftriaxone eradicated 156 of 156 (95% CI: 99.4-100%) urethral and 5 of 5 pharyngeal infections. Among evaluable women, fleroxacin eradicated 127 of 128 (99%; 95% CI: 97.7-100%) cervical, 20 of 20 anorectal, 16 of 16 urethral, and 7 of 7 pharyngeal infections, while ceftriaxone eradicated 108 of 108 (95% CI: 99.1-100%) cervical, 24 of 24 anorectal, 25 of 25 urethral, and 9 of 9 pharyngeal infections. Adverse events were reported by 68 (16%) of 426 subjects in the fleroxacin group and 20 (5%) of 380 in the ceftriaxone group (p < 0.0001). The most common adverse events reported by the patients who received fleroxacin were nausea (5%), headache (3%), and vaginitis (3%). One patient had severe vomiting, 19 participants had adverse reactions classified as moderate, and 48 patients had mild adverse reactions. Fleroxacin was highly effective in the treatment of uncomplicated gonorrhea and represents an oral alternative to ceftriaxone. Adverse events were more common with fleroxacin than with ceftriaxone.

Preparations for AIDS vaccine trials. Developing brief valid screening instruments for HIV-related sexual risk behavior among gay and bisexual men.

Enrolling and tracking cohorts for HIV vaccine efficacy trials requires that participants disclose behaviors that place them at risk for exposure to HIV. Brief screening procedures have been suggested for this purpose. In a previous study gay and bisexual men in three U.S. cities reported unprotected anal intercourse on a brief screening instrument. Screen reports were compared to subsequent in-depth, face-to-face interview data; 29% of the men who reported unprotected anal intercourse during the interview failed to disclose this behavior during screening. For recruitment into an HIV vaccine feasibility study at the same study sites, screening procedures were modified to encourage accurate reporting: to lessen stigma, low risk as well as high risk sexual behaviors were assessed, and screens were administered by trained study staff who presented it as a tool for understanding the gay community. Failures to disclose risk decreased to 18%, a rate that, while lower than in the previous study, remains high. Men less likely to disclose unprotected sex during the screen engaged in fewer high risk sexual behaviors, had more stringent norms regarding sexual safety, and were less identified with the gay community than were men who disclosed unprotected sex. Failure to disclose risk may have significant implications for participant selection and behavior tracking during vaccine trials. More systematic assessments that are sensitive to target communities may facilitate disclosure.

Cryosurgical denervation of the heart: acute and chronic effects.

A newly developed procedure for total cardiac denervation employing cryosurgical techniques is described. Thirty-three dogs underwent cryosurgical cardiac denervation. Twenty-seven survived the procedure and were divided into three groups. Completeness of denervation was evaluated by recording hemodynamic responses to sodium nitroprusside-induced hypotension, phenylephrine-induced hypertension, and direct cardiac autonomic nerve stimulations acutely (group I, n = 11) and 2 weeks after denervation (group II, n = 5). Serial drug infusion studies were performed during an 8-month period in group III animals (n = 11). Myocardial biopsies for catecholamine content were done in groups II and III. Both direct and reflex hemodynamic responses to autonomic neural stimulation were abolished in the acutely denervated hearts. Furthermore, at 2 weeks, direct neural stimulation was without effect, and myocardial catecholamine content was 95% depleted (p less than 0.001). Serial drug infusion studies revealed a changing spectrum of responses, suggesting the onset of reinnervation by 8 months following the procedure. Myocardial catecholamine content was 85% depleted at that time (p less than 0.001). Cryosurgical cardiac denervation is an effective technique offering the advantages of safety, simplicity, and completeness.

Double-inlet ventricle presenting in infancy. I. Survival without definitive repair.

Survival before definitive operations was studied in 191 infants with double-inlet ventricle presenting before 1 year of age (1973 to 1988, median follow-up 8.5 years). The morphologic spectrum was broad, with a great prevalence of associated lesions. The actuarial survival rate before definitive repair was 57% at 1 year, 43% at 5 years, and 42% at 10 years, worse than prior reports because of the younger age at entry into our series. Analysis of univariate risk factors established that right atrial isomerism (18% of the group, relative risk 2.9), common atrioventricular orifice (42%, 2.0), pulmonary atresia (20%, 3.4), obstruction of the systemic outflow tract (18%, 2.5), and extracardiac anomalous pulmonary venous connection (13%, 3.1) were strongly associated with poorer survival. Pulmonary stenosis (40%, 0.35), balanced pulmonary blood flow (9%, 0.40), and presentation at an older age (3%, 0.42 to 0.18) were beneficial (p less than 0.05 to 0.0001). Multivariate analysis allowed the creation of patient-specific curves for prediction of survival for different anatomic and physiologic variants of double-inlet ventricle. A simple additive index was then derived from the multivariate Cox coefficients to enable stratification of risk for these morphologic subgroups of patients and so assist in the making of clinical decisions in infancy.

Recombinant alpha-2 interferon gel treatment of recurrent herpes genitalis.

Topical recombinant alpha-2 interferon treatment of recurrent genital herpes was studied in a randomized, double-blind, placebo controlled clinical trial. Three hundred and eighty-seven patients were treated at eight study centers with either interferon gel or placebo four times daily for four days. Interferon therapy caused a 26% decrease in the duration of viral shedding. For male patients, there were also significant decreases in the time to crusting (17%) and duration of pain (34%) and itching (21%). For patients with recurrent genital herpes, treatment with topical interferon was found to be effective in decreasing the duration of viral shedding and, for males, pain, itching and time to crusting.

Cardiac cryosurgery: effects of myocardial temperature on cryolesion size.

Cryothermic ablation of myocardium and portions of the specialized cardiac conduction tissue has been employed successfully for the treatment of both supraventricular and ventricular tachyarrhythmias. As more uses have been found for cardiac cryosurgery, increasing flexibility of the cryothermia system has been required. The present study was designed to develop a method for electively increasing or decreasing the dimensions and volume of cryolesions by altering adjacent myocardial temperatures. Fourteen dogs were subjected to cardiopulmonary bypass, and standard cryothermic exposures (4 mm cryoprobe, -60 degrees C for 120 seconds) were used to create cryolesions on the left ventricular free wall. The dimensions and volumes of cryolesions created at myocardial temperatures of 37 degrees, 32 degrees, and 6 degrees to 12 degrees C (hypothermic cardioplegic arrest) were compared. Cryolesions created at 6 degrees to 12 degrees C with the dogs under cardioplegic arrest were significantly larger (P less than 0.05) than cryolesions created t 37 degrees or 32 degrees C in the perfused beating heart. This information may be useful in improving the results of myocardial cryoablation, particularly in procedures requiring the ablation of large regions of myocardium or regions deep below the epicardial or endocardial surface.

Noninvasive radionuclide assessment of cardiac function in patients with peripheral vascular disease.

Disorders of the peripheral vascular system often are associated with heart disease which may increase operative risk. The purpose of this study was to investigate the clinical usefulness of radionuclide angiocardiography for evaluation of cardiac function in patients with vascular disorders. This simple procedure provides measurements of cardiac output, pulmonary blood volume, and left ventricular end-diastolic volume, stroke volume, and ejection fraction with no significant risk or discomfort to the patient. A total of 22 patients with vascular disorders were studied by this technique. Five patients had systemic arteriovenous malformations. The cardiac output, end-diastolic volume, and stroke volume were documented to be greater than normal in these patients before operation. In three patients studied following closure of the arteriovenous fistula, the cardiac output, left ventricular end-diastolic volume, and stroke volume decreased. Postoperative changes in left ventricular ejection fraction were variable. A group of 17 patients with atherosclerotic vascular disease underwent cardiac evaluation. In nine patients with no history of cardiac disease, the lowest ejection fraction of 0.45 occurred in a patient with a saccular thoracic aneurysm, the only patient of the 22 who died after operation. A wide variation in ejection fraction was observed in patients with a history of cardiac disease which ranged from 0.32 to 0.86. Objective documentation of cardiac function by radionuclide angiocardiography would appear to enhance the management of patients with peripheral vascular disorders.

Prediction of cervical intraepithelial neoplasia grade 2-3 using risk assessment and human papillomavirus testing in women with atypia on papanicolaou smears.

OBJECTIVE: To determine whether human papillomavirus (HPV) DNA testing and risk assessment can predict cervical intraepithelial neoplasia (CIN) 2-3 on biopsies in women with atypia on Papanicolaou smears. METHODS: One hundred ninety-five consenting women were referred for colposcopy because of atypia on Papanicolaou smears between September 1997 and April 1999. Before colposcopy, women completed risk assessments and had cervical swabs collected for HPV testing using the Hybrid Capture-II assay (Digene Corporation, Silver Spring, MD). Associations of demographic and clinical variables were assessed by chi(2) analysis, and logistic regression was used to assess factors associated with CIN 2-3. The cost-effectiveness of routine colposcopy versus reflex HPV testing by either conventional or liquid-based Papanicolaou smear media was compared. RESULTS: Cervical intraepithelial neoplasia was diagnosed in 70 of 195 women (35.9%), 55 (28.2%) with CIN 1 and 15 (7.7%) with CIN 2-3. High-risk HPV types were detected in 31.3% of all subjects, 36.4% of those with CIN 1, and 93.3% of those with CIN 2-3. By logistic regression, CIN 2-3 was associated only with detection of high-risk HPV (odds ratio 110.08, 95% confidence interval 8.35, 999. 00). The sensitivity of high-risk HPV for detecting CIN 2-3 was 93. 3%, specificity 73.9%, positive predictive value 23.0%, and negative predictive value 99.3%. The cost of reflex HPV testing using conventional smear or liquid-based media was less than routine colposcopy ($4809 and $4308, respectively, versus $4875 per case detected). CONCLUSIONS: Triage based on HPV testing would result in referral of approximately 31% of patients to colposcopy and appears to be a sensitive and cost-effective alternative to colposcopy.

Topical podofilox for the treatment of condylomata acuminata in women.

The purpose of this study was to determine the efficacy and safety of 0.5% podofilox solution (Condylox) for the treatment of genital warts in women. Thirty-seven women with anogenital warts applied the solution to the surface of these warts twice daily for 3 days, followed by 4 drug-free days. A minimum of two and a maximum of four treatment cycles were given. The subjects were evaluated weekly for the first 4 weeks and again at 6 and 10 weeks. At the end of 10 weeks, the mean number of warts per patient was reduced from 6.27 to 1.1, and half of the patients were completely cleared of warts. Only eight of 37 subjects (21.6%) developed new warts during the study period. Approximately 15% of patients reported "severe" local reactions to the treatment after the first treatment cycle, but this was reduced to only 5% by the last treatment cycle. During the same period, the patients reporting no side effects increased from 44 to 86%. The only woman who discontinued the study did so because of dizziness and epigastric discomfort, probably unrelated to drug use. Thus, 0.5% podofilox solution appears to be an effective treatment for condylomata acuminata, with acceptable side effects that are local and temporary.

Candida mediastinitis after a cardiac operation.

Candida mediastinitis is a rare condition characterized by a high mortality and chronic morbidity, Including the present review, only 39 cases have been described, 67% occurring after a cardiac operation. Candida mediastinitis has a 55% mortality in the postoperative setting and a mortality of 92% among patients without a prior cardiac procedure. Although no patient survived Candida mediastinitis without surgical drainage of the mediastinum, survival was 85% among 13 patients who underwent operative mediastinal drainage. Chronic wound infection developed in 6 survivors of operative drainage without muscle flap closure, but in all patients closed with vascularized flaps, healing ultimately occurred. Aggressive surgical management with mediastinal drainage, sternal debridement, and early wound closure with vascularized flaps are essential to minimize the otherwise high morbidity and mortality of Candida mediastinitis.

Ventricular cryosurgery: short-term effects on intramural electrophysiology.

The acute effects of cryothermia on regional electrophysiology were examined in order to devise a means of localizing and monitoring the intramural progression of ventricular cryolesions during a two-minute period of cryothermia application. Intramural unipolar electrograms were recorded from multipoint plunge electrodes placed in the left ventricle in 15 dogs. Epicardial, intramural, and endocardial applications of cryothermia were then employed, and changes in the unipolar peak-to-peak amplitude (UPPA) of electrograms were recorded. The location and depth of the ultimate permanent cryolesion could be predicted by noting locations of those electrograms demonstrating a decrease in the UPPA to less than 30% of the control values. Such electrophysiological monitoring of the region of myocardium undergoing cryothermic ablation provides a means of limiting the ultimate cryolesion to the desired location and depth within the ventricular wall. This allows precise placement of cryolesions in specific areas of the left ventricle for the treatment of ventricular tachyarrhythmias by selectively ablating arrhythmogenic ventricular myocardium without inducing injury in surrounding nonarrhythmogenic myocardium.

Results of valve replacement with mechanical and biological prostheses in chronic renal dialysis patients.

BACKGROUND: Whether biological or mechanical valves should be used in patients on chronic dialysis therapy remains to be clearly defined. METHODS: A retrospective review was performed on 19 consecutive patients from our institution with end-stage renal disease on chronic peritoneal or hemodialysis undergoing aortic (n = 12), mitral (n = 5), or aortic-mitral (n = 2) valve replacement. RESULTS: The 9 biological and 10 mechanical valve patients had similar ages (56.5 versus 56.6 years) and cardiovascular risk factors. The overall estimated Kaplan-Meier survival was 60% +/- 12% at 12 months and 42% +/- 14% at 60 months. Mechanical valve patients had a significantly higher rate of postoperative cerebrovascular accidents or bleeding complications (10/10 versus 0/9; chi 2 = 17.0; p < 0.001). No subsequent reoperations were required for biological valve failure at a mean follow-up of 32 +/- 53 months. CONCLUSIONS: These results demonstrate that in patients with end-stage renal disease, use of mechanical valves is associated with significant risk of complications, whereas biological valve failure from prosthetic dysfunction is unusual. Overall survival is poor in both groups of patients. Therefore, preference should be given to biological valve instead of mechanical valve prostheses in patients on chronic renal dialysis.

Electrophysiologic effects of surgical isolation of the right ventricle.

Surgical isolation of the entire right ventricular free-wall was performed in ten dogs to evaluate the effects of the procedure on a variety of electrophysiologic measurements. Complete surgical isolation of the right ventricle was confirmed by determining that right ventricular electrical activity was not conducted to the remainder of the heart and that electrical activity in the atria or left ventricle did not conduct to the right ventricle. Right ventricular isolation caused no change in right ventricular or left ventricular pacing thresholds, in effective refractory periods of the right ventricle or left ventricle, or in right ventricular free-wall conduction time. Moreover, the normal conduction time from the right atrium to the left ventricle was 139 +/- 5 msec (mean +/- standard error) preoperatively and 135 +/- 5 msec postoperatively (p is not significant), showing that atrial-to-left ventricular synchrony was unaltered by isolation of the right ventricle. However, following isolation, the right ventricle could not be electrically fibrillated in 9 of 10 animals, a finding that may have important implications in the future development of surgical procedures to control chronic, life-threatening ventricular tachyarrhythmias.

Extent of undiagnosed HIV infection in hospitalized patients: assessment by linkage of seroprevalence and surveillance methods.

Routine screening of hospitalized patients for human immunodeficiency virus (HIV) infection has been suggested as a method to identify undiagnosed HIV infection. To evaluate HIV seroprevalence and rates and risk factors for undiagnosed HIV infection among inpatients at an urban hospital, we linked a blinded HIV seroprevalence survey with data from a health care systemwide HIV surveillance registry. Consecutive nonobstetric adult inpatients admitted over four months had remnant samples of serum and plasma obtained and demographic and clinical data abstracted from hospital registration and outpatient encounter billing files. After linkage with the HIV registry, patient data were assigned a study code, individual identifiers were removed, and specimens were tested for HIV-1 antibody. Of 2,825 eligible patients, 155 (5.5%) were HIV-seropositive: 139 (90%) with known infection and 16 (10%) with previously undiagnosed infection. Of those with previously undiagnosed infection, eight (5%) were newly diagnosed during hospitalization and eight (5%) remained undetected following hospitalization. For HIV-seropositive patients, previously undiagnosed infection was significantly more common among those with no use of the health care system in the past year than those with recent outpatient or inpatient visits (41.7% versus 4.6%, odds ratio [OR] = 14.9, 95% confidence intervals [CI] = 4.7, 47.1). Despite a relatively high hospital HIV seroprevalence, the rate of undiagnosed infection was low, suggesting that the percentage of the HIV epidemic remaining "undetected" may be smaller in some settings than suggested by previous studies of hospitalized patients. Linkage of surveillance data to blinded seroprevalence studies can be of value in estimating this "undetected" percentage and in evaluating the potential yield of routine HIV testing programs. Medical Subject Headings (MeSH): HIV infection, risk factors, HIV seroprevalence, inpatients, HIV screening, population surveillance.

Failure to disclose HIV risk among gay and bisexual men attending sexually transmitted disease clinics.

We analyzed data from a multisite study of 1,063 gay or bisexual men attending sexually transmitted disease clinics to evaluate factors predicting failure to disclose human immunodeficiency virus (HIV) risk behaviors to clinic staff and the extent of such failure. We compared data from a brief screening assessment on unprotected anal and oral sex with data on the same behaviors from a subsequent detailed interview. We also compared behavioral data from screening and the interview with data on diagnoses of rectal gonorrhea abstracted from medical charts. Of 523 men reporting unprotected anal sex at interview, 29% failed to report this behavior at screening. Men failing to disclose unprotected anal sex were also less likely to disclose engaging in unprotected oral sex. Among men reporting no unprotected anal sex, either at screening or interview, 1.6% were diagnosed with rectal gonorrhea. Logistic regression analyses comparing men who did and did not disclose at screening having engaged in unprotected anal sex showed that men who failed to disclose reported greater involvement in gay organizations, greater perceived peer support for condoms, fewer episodes of unprotected anal sex in the last four months, and lower rates of substance abuse treatment. Our data suggest that men who failed to disclose may have lower risk levels, and may be more integrated into the gay community. Brief interviews, as opposed to detailed ones, also may underestimate incidence of unsafe sex. Where feasible, HIV risk assessment and counseling and laboratory screening should be routinely provided to all clinic attendees, regardless of self-reports.