Evaluation of Erysipelothrix rhusiopathiae vaccines in pigs by intradermal challenge and immune responses

In a vaccine trial, pigs were challenged intradermally with eight E. rhusiopathiae strains of serovars 1a, 1b or 2 given concurrently. The strains were derived from six herds affected with vaccine breakdowns in 1997-1999, one herd without vaccine breakdown and a serovar 2 reference strain. Responses to two commercial bacterins (one implicated in the vaccine breakdowns), and two experimental bacterins (based on field isolates from affected herds) showed distinct differences in protection, particularly in clinical responses measured at 72 h. Less protection was afforded against serovar 1 challenge by the vaccine implicated in the vaccine breakdowns. Antibody and cell-mediated immune (CMI) responses were significantly different between treatments, and highlighted a similar post-vaccinal antibody response was produced against serovar 2 lysate by all vaccines, but only those providing significant protection against serovar 1 [corrected] produced significantly elevated antiserovar I lysate [corrected] antibodies. Vaccination in general significantly reduced CMI responses to the mitogens concanavalin A and phytohaemagglutinin. This experimental pig challenge system was readily able to confirm suboptimal performance of a commercial bacterin that had passed potency tests in mice but was associated with vaccine failure in commercial herds. This vaccine was also the most immunosuppressive to CMI responses associated with E. rhusiopathiae-specific and non-specific stimulation. The best vaccine response was associated with the highest mean serovar 1 antibody response and the highest CMI response (by lymphoproliferation assay) to serovar 2.

Histone deacetylases in acute myeloid leukaemia show a distinctive pattern of expression that changes selectively in response to deacetylase inhibitors

Histone deacetylase inhibitors (HDIs) are a new class of drugs with significant antileukemic activity. To explore mechanisms of disease-specific HDI activity in acute myeloid leukaemia (AML), we have characterised expression of all 18 members of the histone deacetylase family in primary AML blasts and in four control cell types, namely CD34+ progenitors from umbilical cord, either quiescent or cycling (post-culture), cycling CD34+ progenitors from GCSF-stimulated adult donors and peripheral blood mononuclear cells. Only SIRT1 was consistently overexpressed (>2 fold) in AML samples compared with all controls, while HDAC6 was overexpressed relative to adult, but not neo-natal cells. HDAC5 and SIRT4 were consistently underexpressed. AML blasts and cell lines, exposed to HDIs in culture, showed both histone hyperacetylation and, unexpectedly, specific hypermethylation of H3 lysine 4. Such treatment also modulated the pattern of HDAC expression, with strong induction of HDAC11 in all myeloid cells tested and with all inhibitors (valproate, butyrate, TSA, SAHA), and lesser, more selective, induction of HDAC9 and SIRT4. The distinct pattern of HDAC expression in AML and its response to HDIs is of relevance to the development of HDI-based therapeutic strategies and may contribute to observed patterns of clinical response and development of drug resistance.

Diabetes services in the UK: fourth national survey; are we meeting NSF standards and NICE guidelines?

BACKGROUND

Previous surveys of children's diabetes service provision in the UK have shown gradual improvements but continuing deficiencies.

AIM

To determine whether further improvements in services have occurred.

METHODS

A questionnaire was mailed to all paediatricians in the UK identified as providing care for children and adolescents with diabetes. Responses were compared with results of three previous surveys, and with recommendations in the Diabetes NSF and the NICE type 1 diabetes guidelines.

RESULTS

Replies were received from 187 consultant paediatricians in 169 centres looking after children; 89% expressed a special interest in diabetes, 98% saw children in a designated diabetic clinic, and 95% clinics now have more than 40 patients. In 98% of the clinics there was a specialist nurse (82% now children's trained), but 61% clinics had a nurse:patient ratio <1:100; 39% of clinics did not have a paediatric dietician and in 78% there was no access to psychology/psychiatry services in clinics. Glycated haemoglobin was measured routinely at clinics in 86%, annual screening for retinopathy performed in 80%, and microalbuminuria in 83%. All centres now have local protocols for ketoacidosis, but not for children undergoing surgery (90%) or severe hypoglycaemia (74%). Mean clinic HbA1c levels were significantly lower in the clinics run by specialists (8.9%) than generalists (9.4%). There have been incremental improvements over the last 14 years since the surveys began, but only two clinics met all the 10 previously published recommendations on standards of care.

CONCLUSIONS

The survey shows continuing improvements in organisational structure of services for children with diabetes but serious deficiencies remain. Publication and dissemination of the results of the previous surveys may have been associated with these improvements and similar recurrent service review may be applicable to services for other chronic childhood conditions.

Myxoedema coma

Myxoedema coma is a rare and extreme presentation of hypothyroidism. It has a poor prognosis due to multisystem decompensation, and demands prompt but careful management in a high-dependency / intensive care setting. Early recognition of hypercapnia, hyponatraemia, and sepsis are especially important. Treatment should begin on suspicion of the diagnosis and can be life-saving. Intravenous thyroid hormone replacement is required at first, with steroid cover, although the optimum dose regimen remains unclear.

A 125Te and 23Na NMR investigation of the structure and crystallisation of sodium tellurite glasses

125Te static nuclear magnetic resonance (NMR) and 23Na and 125Te magic angle spinning (MAS) NMR have been used, in conjunction with X-ray diffraction, to examine the structure and crystallisation behaviour of glasses of composition xNa2O.(1-x)TeO2 (0.075 x 0.4). The MAS NMR 23Na spectra from the glasses are broad and featureless but shift by approximately +5 ppm with increased x, i.e. as the system becomes more ionic. The static 125Te NMR spectra show an increase in axial symmetry with increasing x, indicating a shift from predominantly [TeO4] to [TeO3] structural units. The 23Na and 125Te spectra from the crystallised samples have been fitted to obtain information on the sites in the metastable crystal phases, which are the first to form on heating and which are therefore more closely related to the glass structure than thermodynamically stable crystal phases. New sodium tellurite phases are reported, including a sodium stabilised, face centred cubic phase related to delta-TeO2; a metastable form of Na2Te4O9 containing 3 sodium and 4 tellurium sites; and a metastable form of Na2Te2O5 containing 2 sodium sites. There is evidence of oxidation of TeIV to TeVI occurring in glasses with high values of x and, at x=0.40 and 0.50 (outside the glass forming range), some sodium metatellurate (Na2TeO4) is formed at the same time as sodium metatellurite (Na2TeO3). The 125Te shift is very sensitive to environment within the sodium tellurite system, covering more than 320 ppm, with anisotropies varying from 640 to 1540 ppm. The lack of features in the 125Te spectra of the glass phases, combined with the large shift range and high but variable anisotropy, means than it is not possible to obtain a unique fit to any presumed species present. Furthermore, the chemical shift anisotropy parameters for three of the four Te sites in the Na2Te4O9 phase are found to lie outside the range used for previous simulations of glass spectra.

Reduced forearm reactive hyperaemia in normoalbuminuric subjects with Type 1 diabetes and retinopathy

AIM

To determine whether the forearm vasodilatory response to reactive hyperaemia (RH) is reduced in normoalbuminuric subjects with Type 1 diabetes mellitus and retinopathy compared with subjects with no retinopathy.

METHODS

Forearm RH, an indicator of endothelial function, was measured, using strain-gauge plethysmography, in 39 normoalbuminuric subjects (22 with retinopathy) with long-standing Type 1 diabetes mellitus.

RESULTS

were evaluated in relation to conventional risk factors for atherosclerosis, and C-reactive protein (CRP), which we have recently determined to be an independent correlate of forearm RH.

RESULTS

Forearm RH was decreased in subjects with retinopathy compared with those with no retinopathy (219 +/- 182 vs. 473 +/- 355, P < 0.01). Both retinopathy and CRP proved to be independent and negative predictors, and explain 27% of the variance, in forearm RH.

CONCLUSION

Retinopathy in subjects with Type 1 diabetes mellitus may reflect a generalized process of endothelial dysfunction, even in the absence of microalbuminuria.

Use of cancer susceptibility testing among primary care physicians

Primary care physicians (PCPs) are assuming greater roles in cancer risk assessment and susceptibility testing of patients. The objective of this study was to assess the beliefs and practices of PCPs relative to genetic susceptibility testing for cancer. A cross-sectional survey was mailed to 726 PCPs in community-based practices in southeastern Pennsylvania and southern New Jersey. Data were collected on physician background, cognitive and psychosocial factors, practice environment, and patient factors. The main outcome measure was physician self-reported recommendation or referral of patients for cancer genetic susceptibility testing in a 12-month period prior to the survey. Of those surveyed, 475 (65%) PCPs responded. Complete survey data were available for 433 PCPs. Multivariable analyses show that factors positively associated with PCP recommendation/referral included: patient inquiry about their need for genetic testing for cancer (p < 0.001); PCP belief that patient age is the best predictor of cancer risk (p = 0.01); PCP self-reported frequency of collecting patient diet information (p = 0.01) and medical history information (p = 0.01); and PCP participation in an integrated health system (p = 0.01). PCP use of cancer genetic susceptibility testing may be influenced by patient inquiry, provider beliefs about factors that affect cancer risk, provider collection of risk-assessment data, and provider practice environment.

Spinal cord atrophy and disability in multiple sclerosis over four years: application of a reproducible automated technique in monitoring disease progression in a cohort of the interferon beta-1a (Rebif) treatment trial

BACKGROUND

Pathology in the cervical spinal cord is considered an important cause of disability in multiple sclerosis. However, the majority of serial studies have failed to find a correlation between spinal cord atrophy and disability.

OBJECTIVES

To use a highly reproducible and accurate method to quantify spinal cord area change on three dimensional magnetic resonance imaging and relate this to disability change in patients with multiple sclerosis.

METHODS

38 patients with multiple sclerosis (20 with the relapsing-remitting (RRMS) form and 18 with the secondary progressive (SPMS) form) were imaged at baseline and at months 6, 12, 18, and 48 during two treatment trials of the high dose subcutaneous thrice weekly interferon beta-1a (IFNbeta, Rebif). Thirty one healthy subjects were also imaged at baseline. Upper cervical cord area (UCCA) was measured using Sobel edge detection.

RESULTS

The intraobserver coefficient of variation of the method was 0.42%. A significant reduction in UCCA was detected at month 6 in the placebo group (p = 0.04) and at month 12 for INFbeta (p = 0.03). The mean reduction of UCCA at month 48 was 5.7% for patients initially on placebo who received treatment at 24 months (RRMS) or at 36 months (SPMS), and 4.5% for those on IFNbeta throughout the study (p = 0.35). The change in UCCA was significantly correlated with change in the expanded disability status scale at month 12 (r = 0.4, p = 0.016), month 18 (r = 0.32, p = 0.05), and month 48 (r = 0.4, p = 0.016) in the total cohort.

CONCLUSIONS

Despite the small number of patients studied and the possible confounding effects of interferon treatment, this study showed that edge detection is reproducible and sensitive to changes in spinal cord area, and that this change is related to changes in clinical disability. This suggests a role for measurement of spinal cord atrophy in monitoring disease progression and possible treatment effects in clinical trails.

Low temperature episodes in development of blowflies: implications for postmortem interval estimation

Traditionally the calculation of accumulated degree days or hours (ADD or ADH) involves the concept of a minimum threshold temperature below which development ceases. Hence in fluctuating conditions, where temperatures drop below this threshold, there may be periods of time when development is taken to be zero. This has important implications when the calculation of postmortem interval (PMI) is based on the ADD or ADH of larval dipterans. Normal development of larvae of the blowflies Calliphora vicina Robineau-Desvoidy and C. vomitoria L. (Diptera: Calliphoridae) at 20 degrees C was interrupted by cold episodes. The expectation was that total development time would increase by the period at low (therefore no development) temperature but the total ADD or ADH should be the same as non-cold treated cohorts. The results, however, showed that total ADH for both species decreased linearly with increasing temperature with no evidence of any minimum threshold temperature effect. The increased ADH at low temperatures may be due to either continued but reduced development or a delay in development restarting after the cold episode. Use of ADH in PMI estimations has shortcomings particularly during the winter period where low temperatures are involved or where there are sudden summer cold spells during the development period. As blowfly development progresses from egg to pupa such errors will be compounded.

Diabetes UK funded surveys of the structural provision of primary care diabetes services in the UK

AIM

To describe diabetes service provision in primary care in the UK.

METHODS

Postal questionnaires were sent to all UK primary care organizations (PCOs), and to a sample of general practices in England and all practices in Wales and Scotland. The data collection period ended on 30 April 2001.

RESULTS

Seventy-nine per cent of the PCOs and 40% of the practices provided usable information. There is evidence that respondents were not significantly biased in relation to their interest in diabetes care. Diabetes was included as a Health Improvement Programme (or equivalent) priority by 62% of PCOs and had been identified as a clinical governance priority by 27%. Sixty-five per cent had information about the ethnic composition of their general population, 57% had an estimate of the number of people with diabetes. Sixty-nine per cent had a local diabetes register but this was said to cover the entire local population in only 64% of these. At least one audit of diabetes care had been carried out (in the previous 5 years) in 75% and, in 76%, clinical guidelines on diabetes care were made available to practices. In the practices, 80% had a designated lead person for diabetes. Seventy-three per cent had at least one general practitioner with a special interest and 87% at least one nurse. Seventy-two per cent of practices ran specific diabetes clinics and 51% had a screening policy. Eighty-six per cent considered that they had adequate systems in place for the delivery of diabetes care. However, only 6% were able to offer a dedicated diabetes telephone help or advice line and only 9% an evening out of hours clinic. Regular practice meetings were held to discuss diabetes in 35%, whereas 39% had a formal shared care protocol. Fourteen per cent held regular joint meetings with the hospital-based team and in 38% there was membership of Diabetes UK for at least one partner or the practice itself. A third (34%) of responding practices were unsure whether a Local Diabetes Services Advisory Group or equivalent existed in their area. Geographical differences in service provision were identified with, for example, practices in London having fewer components in place that were specifically related to the provision of diabetes care. Single-handed practices, wherever they were situated, had in place fewer staff and facilities specifically for diabetes care.

Changes in third ventricular size with neuroendoscopic third ventriculostomy: a blinded study

The objective was to study the relation between changes in cerebral ventricular size and clinical outcome after neuroendoscopic third ventriculostomy (NTV) in both primary (no previous surgery) and secondary (previous CSF diversion for hydrocephalus) NTV. Changes in ventricular size were related to the need for further surgery for CSF diversion. A blinded retrospective study of the pre-NTV and post-NTV sizes of the ventricles in an unselected series of patients undergoing this procedure was done. A decrease in third ventricular size was seen in significantly more patients in the primary group than in the secondary group. Median change in third ventricle width for those who did not require further CSF diversion was significantly greater than those with no clinical benefit (p=0.01). Positive predictive power for successful outcome was highest for measures of the third ventricle; 73% and 68% for third ventricle width and height respectively, 88% for anterior to posterior commissure distance. In conclusion, third ventricular size reduces after NTV. The use of such a change as an arbiter of success in this procedure is questionable as clinically successful cases can have no change in ventricular size. It is considered that clinical outcome is the most important guide to success or failure as reduction in ventricular size is by no means guaranteed. Radiological outcomes alone may be misleading and reliance on them should be avoided.

Dermatitis herpetiformis and neurological dysfunction

Dermatitis herpetiformis and coeliac disease are gluten sensitive diseases, which have common immunopathological and genetic mechanisms. Neuropsychiatric complications have been reported in up to 26% of patients with coeliac disease. This is probably an overestimate, because of the chance associations with some common neurological conditions such as epilepsy. The pathogenesis is speculative but it has been postulated that gluten is neurotoxic possibly via immune mechanisms. The frequency of neurological dysfunction in patients with dermatitis herpetiformis has not been characterised. Patients with dermatitis herpetiformis might be expected to be particularly susceptible to neuronal damage as some continue to consume gluten when their dermatological symptoms are controlled by dapsone. Thirty five patients were recruited with dermatitis herpetiformis from dermatology clinics at St Mary's Hospital, London and Queen's Medical Centre, Nottingham and investigated for evidence of neurological abnormality. All patients underwent a full neurological examination and were asked about their neurological and general medical history by means of a structured questionnaire. Serum samples were taken and screened for the presence of anti-neuronal antibodies (anti-Hu and Yo) as well as anti-gliadin (IgA and G) anti-endomysial (IgA), and anti-tissue transglutaminase (IgA) antibodies. Neurophysiological tests were carried out where appropriate. Only two patients were identified with unexplained neurological abnormalities (one essential tremor, and one chorea). Two other patients had a history of migraine. The patient with chorea also had borderline/equivocally positive anti-Hu antibodies by immunofluorescence assay. All other samples were negative for anti-neuronal antibodies. Fifteen patients were positive for anti-gliadin antibodies (IgA and/or IgG), four for anti-endomysial antibodies (monkey oesophagus or umbilical cord), and six for anti-tissue transglutaminase antibodies. The presence of these antibodies did not correlate with the presence of neurological abnormalities. No cases of "gluten ataxia" were identified. In conclusion, there was no convincing evidence for immune mediated neurological damage in this pilot study of dermatitis herpetiformis.

Underuse of primary Mycobacterium avium complex and Pneumocystis carinii prophylaxis in the United States

BACKGROUND

Little is known about the rates of Mycobacterium avium complex (MAC) and Pneumocystis carinii (PCP) prophylaxis adherence to guidelines and how they have changed after introduction of effective antiretroviral therapy.

OBJECTIVE

To determine rates of primary prophylaxis for MAC and PCP and to evaluate the influence of sociodemographic characteristics, region, and provider experience.

DESIGN

National probability sample cohort of HIV patients in care.

SETTING

One hundred sixty HIV health care providers.

PATIENTS

A total of 2864 patients interviewed in 1996 to 1997 (68% response) and 2267 follow-up interviews, representing 65% of surviving sampled patients (median follow-up, 15.1 months).

MEASUREMENTS

Use of prophylactic drugs, most recent CD4 count, sociodemographics, and regional and total HIV patients/providers.

RESULTS

Of patients eligible for primary MAC prophylaxis (most recent CD4 count <50/mm(3) ), 41% at baseline and 40% at follow-up patients were treated. Of patients eligible for primary PCP prophylaxis (i.e., those with CD4 counts <200/mm(3) ), 64% and 72% were treated, respectively. MAC prophylaxis at baseline was less likely in African American (adjusted odds ratio [OR], 35; 95% confidence interval [CI], 0.20-0.59), Hispanic (OR, 27; 95% CI, 0.08-0.94) and less-educated (OR, 0.61; 95% CI, 0.36-1.0) patients and more likely in U. S. geographic regions in the Pacific West (OR, 4.9; 95% CI, 1.0-23) and Midwest (OR, 6.4; 95% CI, 1.2-33) and in practices with more HIV patients.

CONCLUSIONS

Most eligible patients did not receive MAC prophylaxis; PCP prophylaxis rates were better but still suboptimal. Our results support outreach efforts to African Americans, Hispanics, the less educated, and those in the northeastern United States and in practices with fewer HIV patients.

Long-term predictors of coronary artery disease and mortality in type 1 diabetes

We assessed clinical and biochemical predictors of death and/or cardiovascular disease in 147 type 1 diabetes mellitus (DM) patients followed-up for 14 years. At follow-up, 28 of patients (19%) had died, and 25 patients (18%) had developed or died of coronary artery disease (CAD). At baseline, those who died had significantly higher serum creatinine (p=0.001) and urine albumin/creatinine ratio (p=0.016), greater prevalence of retinopathy (p=0.006), lower serum apolipoprotein A1 (p=0.046), and lower daily insulin dose (p=0.024) than those who survived. CAD patients had a longer duration of diabetes (p<0.001), were older at the onset of diabetes and at presentation (p=0.001), and had higher prevalences of retinopathy (p=0.005) and neuropathy (p=0.016). The CAD group also had higher baseline serum creatinine (p=0.02), lower HDL cholesterol (p=0.004) and apolipoprotein A1 (p=0.007) and higher LDL cholesterol (p=0.028) and apolipoprotein B concentrations (p=0.027). Under logistic regression analysis (adjusted for age and sex), baseline urine albumin/creatinine ratio (p=0.003), presence of retinopathy (p=0.004), serum creatinine (p=0.028), and serum urea (p=0.034) were the most powerful predictors of mortality, while duration of diabetes (p<0.0001), baseline HDL cholesterol (p=0.012), serum creatinine (p=0.02), apolipoprotein B (p=0.038), LDL cholesterol (p=0.039), and systolic blood pressure (p=0.055) were the strongest predictors of CAD. These findings emphasize the role of abnormal lipoprotein metabolism in the development of CAD in type 1 DM. Indicators of renal impairment and the presence of retinopathy seem to be of greater importance in predicting overall mortality.

Identification of a conserved erythroid specific domain of histone acetylation across the alpha-globin gene cluster

We have analyzed the pattern of core histone acetylation across 250 kb of the telomeric region of the short arm of human chromosome 16. This gene-dense region, which includes the alpha-globin genes and their regulatory elements embedded within widely expressed genes, shows marked differences in histone acetylation between erythroid and non-erythroid cells. In non-erythroid cells, there was a uniform 2- to 3-fold enrichment of acetylated histones, compared with heterochromatin, across the entire region. In erythroid cells, an approximately 100-kb segment of chromatin encompassing the alpha genes and their remote major regulatory element was highly enriched in histone H4 acetylated at Lys-5. Other lysines in the N-terminal tail of histone H4 showed intermediate and variable levels of enrichment. Similar broad segments of erythroid-specific histone acetylation were found in the corresponding syntenic regions containing the mouse and chicken alpha-globin gene clusters. The borders of these regions of acetylation are located in similar positions in all three species, and a sharply defined 3' boundary coincides with the previously identified breakpoint in conserved synteny between these species. We have therefore demonstrated that an erythroid-specific domain of acetylation has been conserved across several species, encompassing not only the alpha-globin genes but also a neighboring widely expressed gene. These results contrast with those at other clusters and demonstrate that not all genes are organized into discrete regulatory domains.

Complete diagnostic evaluation in colorectal cancer screening: research design and baseline findings

BACKGROUND

While indicated by guidelines, complete diagnostic evaluation, or CDE (i.e., colonoscopy or combined flexible sigmoidoscopy plus barium enema X ray), is often not recommended and performed for persons with an abnormal screening fecal occult blood test (FOBT) result. We initiated a randomized trial to assess the impact of a physician-oriented intervention on CDE rates in primary care practices.

METHODS

In 1998, we identified 1,184 primary care physicians (PCPs) in 584 practices whose patients received FOBTs that are mailed annually by a managed care organization screening program. A total of 470 PCPs in 318 practices completed a baseline survey. Practices were randomly assigned either to a Control Group (N = 198) or to an Intervention Group (N = 120). Control Group practices received the screening program. Intervention Group practices received the screening program and the intervention (i.e., CDE reminder-feedback plus educational outreach). Practice CDE recommendation and performance rates are the primary outcomes to be measured in the study.

RESULTS

Baseline CDE recommendation and performance rates were low and were comparable in Control and Intervention Group practices (54 to 57% and 39 to 40%, respectively). PCPs in the practices tended to view FOBT screening and CDE favorably, but had concerns about screening efficacy, time involved in CDE, and patient discomfort and adherence. Control Group physicians were more likely than Intervention Group physicians to believe that a mail-out FOBT screening program helps in the practice of medicine.

CONCLUSIONS

We were able to enroll a high proportion of targeted primary care practices, measure practice characteristics and CDE rates at baseline, and develop and implement the intervention. Study outcome analyses will take into account baseline differences in practice characteristics.

Enhancing the specificity of the COBAS AMPLICOR CT/NG test for Neisseria gonorrhoeae by retesting specimens with equivocal results

The COBAS AMPLICOR CT/NG test for Neisseria gonorrhoeae cross-reacts with certain strains of nonpathogenic Neisseria species. In some strains, the target sequence is identical to that of N. gonorrhoeae, whereas other strains have a small number of mismatches within the regions recognized by the primers or probe used in the COBAS AMPLICOR NG test. These cross-reactive strains are occasionally present in urogenital specimens, causing false-positive results in the COBAS AMPLICOR NG test. Analysis of the data generated in a large multicenter clinical trial showed that 2.9% of the specimens gave signals between A(660)s of 0.2 and 3.5 but that one-half of these equivocal specimens did not contain N. gonorrhoeae. Most of these equivocal specimens were correctly classified as true positive or true negative by retesting in duplicate and defining a PCR-positive result as two of three results with an A(660) of > or =2.0. If specimens had been classified as positive or negative based on a single test result using a cutoff of an A(660) of 0.2, specificity would have ranged from 96.2 to 98.9% depending on specimen type, sex, and presence of symptoms. By employing the equivocal zone-retesting algorithm, specificity increased to 98.6 to 99.9% with little effect (0.1 to 4.9% decrease) on sensitivity in most specimen types, enabling the test to achieve a positive predictive value of at least 90% in populations with a prevalence of 4% or higher. In lower-prevalence populations, the test could be used to screen for presumptive infections that would have to be confirmed by an independent test.