Access to diagnostics in support of HIV/AIDS and tuberculosis treatment in developing countries

Cyclopentane peptide nucleic acid: Gold nanoparticle conjugates for the detection of nucleic acids in a microfluidic format

Routine patient testing for viral infections is critical to identify infected individuals for treatment and to prevent spreading of infections to others. Developing robust and reliable diagnostic tools to detect nucleic acids of viruses at the point-of-care could greatly assist the clinical management of viral infections. The remarkable stability and high binding affinity of peptide nucleic acids (PNAs) to target nucleic acids could make PNA-based biosensors an excellent starting point to develop new nucleic acid detection technologies. We report the application of cyclopentane-modified PNAs to capture target nucleic acids in a microfluidic channel, and the use of bioorthogonal PNAs conjugated to gold nanoparticles as probes to semi-quantitatively signal the presence of a target nucleic acid derived from HIV-1. The basic results presented could be used to develop more advanced devices to detect nucleic acids from viruses such as HIV, SARS-CoV-2, and a wide range of other human diseases.

Improving sepsis care in Africa: an opportunity for change?

Sepsis is common and represents a major public health burden with significant associated morbidity and mortality. However, despite substantial advances in sepsis recognition and management in well-resourced health systems, there remains a distinct lack of research into sepsis in Africa. The lack of evidence affects all levels of healthcare delivery from individual patient management to strategic planning at health-system level. This is particular pertinent as African countries experience some of the highest global burden of sepsis. The 2017 World Health Assembly resolution on sepsis and the creation of the Africa Sepsis Alliance provided an opportunity for change. However, progress so far has been frustratingly slow. The recurrent Ebola virus disease outbreaks and the COVID-19 pandemic on the African continent further reinforce the need for urgent healthcare system strengthening. We recommend that African countries develop national action plans for sepsis which should address the needs of all critically ill patients.

Clinico-pathological discrepancies in the diagnosis of causes of death in adults in Mozambique: A retrospective observational study

Background

Clinico-pathological discrepancies are more frequent in settings in which limited diagnostic techniques are available, but there is little information on their actual impact.

Aim

We assessed the accuracy of the clinical diagnoses in a tertiary referral hospital in sub-Saharan Africa by comparison with post-mortem findings. We also identified potential risk factors for misdiagnoses.

Methods

One hundred and twelve complete autopsy procedures were performed at the Maputo Central Hospital (Mozambique), from November 2013 to March 2015. We reviewed the clinical records. Major clinico-pathological discrepancies were assessed using a modified version of the Goldman and Battle classification.

Results

Major diagnostic discrepancies were detected in 65/112 cases (58%) and were particularly frequent in infection-related deaths (56/80 [70%] major discrepancies). The sensitivity of the clinical diagnosis for toxoplasmosis was 0% (95% CI: 0–37), 18% (95% CI: 2–52) for invasive fungal infections, 25% (95% CI: 5–57) for bacterial sepsis, 34% (95% CI: 16–57), for tuberculosis, and 46% (95% CI: 19–75) for bacterial pneumonia. Major discrepancies were more frequent in HIV-positive than in HIV-negative patients (48/73 [66%] vs. 17/39 [44%]; p = 0.0236).

Conclusions

Major clinico-pathological discrepancies are still frequent in resource constrained settings. Increasing the level of suspicion for infectious diseases and expanding the availability of diagnostic tests could significantly improve the recognition of common life-threatening infections, and thereby reduce the mortality associated with these diseases. The high frequency of clinico-pathological discrepancies questions the validity of mortality reports based on clinical data or verbal autopsy.

Comparison of a new in-house HIV-1 TaqMan real-time PCR and three commercial HIV-1 RNA quantitative assays

OBJECTIVES

The aim of this study was to compare the analytical performance of an In-House HIV-1 viral load determination technique with three commercial kits including COBAS^® AmpliPrep, RealStar^®, and RTA^® HIV-1 Real-Time PCR.

RESULTS

A total of 100 HIV-1 suspicious plasma samples were tested by the In-House TaqMan^® Real-Time PCR assay along with the above-mentioned kits. Comparative analysis between In-House and reference method (COBAS^® AmpliPrep/COBAS^® TaqMan^® HIV-1 Test version 2.0) showed high concordance with a mean difference of 0.08 log₁₀ copies/ml. All samples results were within -0.16-0.31 log₁₀ copies/ml. A suitable correlation was obtained with a coefficient (R²) of 0.82 between the In-House assay and RTA^® Kit, however, two positive samples were not detected. The lowest agreement was detected with RealStar^® HIV Kit 1.0 (R² = 0.49, r = 0.7).

CONCLUSIONS

The newly developed method has suitable sensitivity, accuracy, and precision. In addition, it is cost-effective and can be an alternative in all laboratories.

Laboratory medicine in Africa since 2008: then, now, and the future

The Maputo Declaration of 2008 advocated for commitment from global stakeholders and national governments to prioritise support and harmonisation of laboratory systems through development of comprehensive national laboratory strategies and policies in sub-Saharan Africa. As a result, HIV laboratory medicine in Africa has undergone a transformation, and substantial improvements have been made in diagnostic services, networks, and institutions, including the development of a competent workforce, introduction of point-of-care diagnostics, and innovative quality improvement programmes that saw more than 1100 laboratories enrolled and 44 accredited to international standards. These improved HIV laboratories can now be used to combat emerging continental and global health threats in the decades to come. For instance, the unprecedented Ebola virus disease outbreak in west Africa exposed the severe weaknesses in the overall national health systems in affected countries. It is now possible to build robust health-care systems in Africa and to combat emerging continental and global health threats in the future. In this Personal View, we aim to describe the remarkable transformation that has occurred in laboratory medicine to combat HIV/AIDS and improve global health in sub-Saharan Africa since 2008.

Performance of health laboratories in provision of HIV diagnostic and supportive services in selected districts of Tanzania

Background

Roll-out and implementation of antiretroviral therapy (ART) necessitated many countries in Sub-Saharan Africa to strengthen their national health laboratory systems (NHLSs) to provide high quality HIV diagnostic and supportive services. This study was conducted to assess the performance of health laboratories in provision of HIV diagnostic and supportive services in eight districts (from four regions of Iringa, Mtwara, Tabora and Tanga), after nine years of implementation of HIV/AIDS care and treatment plan in Tanzania.

Methods

In this cross-sectional study, checklists and observations were utilized to collect information from health facilities (HFs) with care and treatment centres (CTCs) for HIV/AIDS patients; on availability of laboratories, CTCs, laboratory personnel, equipment and reagents. A checklist was also used to collect information on implementation of quality assurance (QA) systems at all levels of the NHLS in the study areas.

Results

The four regions had 354 HFs (13 hospitals, 41 Health Centres (HCs) and 300 dispensaries); whereby all hospitals had laboratories and 11 had CTCs while 97.5 and 61.0% of HCs had both laboratories and CTCs, respectively. Of the dispensaries, 36.0 and 15.0% had laboratories and CTCs (mainly in urban areas). Thirty nine HFs (12 hospitals, 21 HCs and six dispensaries) were assessed and 56.4% were located in urban areas. The assessed HFs had 199 laboratory staff of different cadres (laboratory assistants = 35.7%; technicians =32.7%; attendants = 22.6%; and others = 9.1%); with >61% of the staff and 72.3% of the technicians working in urban areas. All laboratories were using rapid diagnostic tests for HIV testing. Over 74% of the laboratories were performing internal quality control and 51.4% were participating in external QA programmes. Regional and district laboratories had all key equipment and harmonization was maintained for Fluorescence-Activated Cell Sorting (FACS) machines. Most of the biochemical (58.0%) and haematological analysers (74.1%) were available in urban areas. Although >81% of the equipment were functional with no mechanical faulty, 62.6% had not been serviced in the past three years.

Conclusion

Diagnostic and supportive services for HIV were available in most of the HCs and hospitals while few dispensaries were providing the services. Due to limitations such as shortage of staff, serving of equipment and participation in QA programmes, the NHLS should be strengthened to ensure adequate human resource, implementation of QA and sustainable preventive maintenance services of equipment.

Using BD Vacutainer CD4 Stabilization Tubes for Absolute Cluster of Differentiation Type 4 Cell Count Measurement on BD FacsCount and Partec Cyflow Cytometers: A Method Comparison Study from Zimbabwe

Background

Blood collected in conventional EDTA tubes requires laboratory analysis within 48 hours to provide valid CD4 cell count results. This restricts access to HIV care for patients from rural areas in resource-constraint settings due to sample transportation problems. Stabilization Tubes with extended storage duration have been developed but not yet evaluated comprehensively.

Objective

To investigate stability of absolute CD4 cell count measurement of samples in BD Vacutainer CD4 Stabilization Tubes over the course of 30 days.

Methods

This was a laboratory-based method comparison study conducted at a rural district hospital in Beitbridge, Zimbabwe. Whole peripheral blood from 88 HIV positive adults was drawn into BD Vacutainer CD4 Stabilization Tubes and re-tested 1, 2, 3, 5, 7, 14 and 30 days after collection on BD FacsCount and Partec Cyflow cytometers in parallel. Absolute CD4 cell levels were compared to results from paired samples in EDTA tubes analysed on BD FacsCount at the day of sample collection (references methodology). Bland-Altman analysis based on ratios of the median CD4 counts was used, with acceptable variation ranges for Limits of Agreements of +/-20%.

Results

Differences in ratios of the medians remained below 10% until day 21 on BD FacsCount and until day 5 on Partec Cyflow. Variations of Limits of Agreement were beyond 20% after day 1 on both cytometers. Specimen quality decreased steadily after day 5, with only 68% and 40% of samples yielding results on BD FacsCount and Partec Cyflow at day 21, respectively.

Conclusions

We do not recommend the use of BD Vacutainer CD4 Stabilization Tubes for absolute CD4 cell count measurement on BD FacsCount or Partec Cyflow due to large variation of results and decay of specimen quality. Alternative technologies for enhanced CD4 testing in settings with limited laboratory and sample transportation capacity still need to be developed.

New technologies for essential newborn care in under-resourced areas: what is needed and how to deliver it

Globally, the largest contributors to neonatal mortality are preterm birth, intrapartum complications and infection. Many of these deaths could be prevented by providing temperature stability, respiratory support, hydration and nutrition; preventing and treating infections; and diagnosing and treating neonatal jaundice and hypoglycaemia. Most neonatal health-care technologies which help to accomplish these tasks are designed for high-income countries and are either unavailable or unsuitable in low-resource settings, preventing many neonates from receiving the gold standard of care. There is an urgent need for neonatal health-care technologies which are low-cost, robust, simple to use and maintain, affordable and able to operate from various power supplies. Several technologies have been designed to meet these requirements or are currently under development; however, unmet technology needs remain. The distribution of an integrated set of technologies, rather than separate components, is essential for effective implementation and a substantial impact on neonatal health. Close collaboration between stakeholders at all stages of the development process and an increased focus on implementation research are necessary for effective and sustainable implementation.

Access to CD4 Testing for Rural HIV Patients: Findings from a Cohort Study in Zimbabwe

Background

CD4 cell count measurement remains an important diagnostic tool for HIV care in developing countries. Insufficient laboratory capacity in rural Sub-Saharan Africa is frequently mentioned but data on the impact at an individual patient level are lacking. Urban-rural discrepancies in CD4 testing have not been quantified to date. Such evidence is crucial for public health planning and to justify new yet more expensive diagnostic procedures that could circumvent access constraints in rural areas.

Objective

To compare CD4 testing among rural and urban HIV patients during the first year of treatment.

Methods

Records from 2,145 HIV positive adult patients from a Médecins sans Frontières (Doctors without Borders) HIV project in Beitbridge, Zimbabwe, during 2011 and 2012 were used for a retrospective cohort analysis. Covariate-adjusted risk ratios were calculated to estimate the effects of area of residence on CD4 testing at treatment initiation, six and 12 months among rural and urban patients.

Findings

While the proportion of HIV patients returning for medical consultations at six and 12 months decreased at a similar rate in both patient groups, CD4 testing during consultations dropped to 21% and 8% for urban, and 2% and 1% for rural patients at six and 12 months, respectively. Risk ratios for missing CD4 testing were 0.8 (95% CI 0.7-0.9), 9.2 (95% CI 5.5-15.3), and 7.6 (95% 3.7-17.1) comparing rural versus urban patients at treatment initiation, six and 12 months, respectively.

Conclusions

CD4 testing was low overall, and particularly poor in rural patients. Difficulties with specimen transportation were probably a major factor underlying this difference and requires new diagnostic approaches. Our findings point to severe health system constraints in providing CD4 testing overall that need to be addressed if effective monitoring of HIV patients is to be achieved, whether by alternative CD4 diagnostics or newly-recommended routine viral load testing.

Enhanced Sensitivity for Detection of HIV-1 p24 Antigen by a Novel Nuclease-Linked Fluorescence Oligonucleotide Assay

The relatively high detection limit of the Enzyme-linked immunosorbent assay (ELISA) prevents its application for detection of low concentrations of antigens. To increase the sensitivity for detection of HIV-1 p24 antigen, we developed a highly sensitive nuclease-linked fluorescence oligonucleotide assay (NLFOA). Two major improvements were incorporated in NLFOA to amplify antibody-antigen interaction signals and reduce the signal/noise ratio; a large number of nuclease molecules coupled to the gold nanoparticle/streptavidin complex and fluorescent signals generated from fluorescent-labeled oligonucleotides by the nuclease. The detection limit of p24 by NLFOA was 1 pg/mL, which was 10-fold more sensitive than the conventional ELISA (10 pg/mL). The specificity was 100% and the coefficient of variation (CV) was 7.8% at low p24 concentration (1.5 pg/mL) with various concentrations of spiked p24 in HIV-1 negative sera. Thus, NLFOA is highly sensitive, specific, reproducible and user-friendly. The more sensitive detection of low p24 concentrations in HIV-1-infected individuals by NLFOA could allow detection of HIV-1 infections that are missed by the conventional ELISA at the window period during acute infection to further reduce the risk for HIV-1 infection due to the undetected HIV-1 in the blood products. Moreover, NLFOA can be easily applied to more sensitive detection of other antigens.

Inpatient mortality of HIV-infected adults in sub-Saharan Africa and possible interventions: a mixed methods review

Background

Despite the increased availability of anti-retroviral therapy, in-hospital HIV mortality remains high in sub-Saharan Africa. Reports from Senegal, Malawi, and Tanzania show rates of in-hospital, HIV-related mortality ranging from 24.2% to 44%. This mixed methods review explored the potential causes of preventable in-hospital mortality associated with HIV infections in sub-Saharan Africa in the anti-retroviral era.

Results

Based on our experience as healthcare providers in Africa and a review of the literature we identified 5 health systems failures which may cause preventable in-hospital mortality, including: 1) late presentation of HIV cases, 2) low rates of in-hospital HIV testing, 3) poor laboratory capacity which limits CD4 T-cell testing and the diagnosis of opportunistic infections, 4) delay in initiation of anti-retroviral therapy in-hospital, and 5) problems associated with loss to follow-up upon discharge from hospital.

Conclusion

Our findings, together with the current available literature, should be used to develop practical interventions that can be implemented to reduce in-hospital mortality.

Clinical utility of a novel molecular assay in various combination strategies with existing methods for diagnosis of HIV-related tuberculosis in Uganda

BACKGROUND

Low income, high-tuberculosis burden, countries are considering selective deployment of Xpert MTB/RIF assay (Xpert) due to high cost per test. We compared the diagnostic gain of the Xpert add-on strategy with Xpert replacement strategy for pulmonary tuberculosis diagnosis among HIV-infected adults to inform its implementation.

METHODS

The first diagnostic sputum sample of 424 HIV-infected adults (67% with CD4 counts ≤200/mm3) suspected for tuberculosis was tested by direct Ziehl-Neelsen (DZN) and direct fluorescent microscopy (DFM); concentrated fluorescent microscopy (CFM); Lowenstein-Jensen (LJ) and Mycobacterial Growth Indicator Tube (MGIT) culture; and Xpert. Overall diagnostic yield and sensitivity were calculated using MGIT as reference comparator. The sensitivity of Xpert in an add-on strategy was calculated as the number of smear negative but Xpert positive participants among MGIT positive participants.

RESULTS

A total of 123 (29.0%) participants were MGIT culture positive for Mycobacterium tuberculosis. The sensitivity (95% confidence interval) was 31.7% (23.6-40.7%) for DZN, 35.0% (26.5-44.0%) for DFM, 43.9% (34.9-53.1%) for CFM, 76.4% (67.9-83.6) for Xpert and 81.3% (73.2-87.7%) for LJ culture. Add-on strategy Xpert showed an incremental sensitivity of 44.7% (35.7-53.9%) when added to DZN, 42.3% (33.4-51.5%) to DFM and 35.0% (26.5-44.0%) to CFM. This translated to an overall sensitivity of 76.4%, 77.3% and 79.0% for add-on strategies based on DZN, DFM and CFM, respectively, compared to 76.4% for Xpert done independently. From replacement to add-on strategy, the number of Xpert cartridges needed was reduced by approximately 10%.

CONCLUSIONS

Among HIV-infected TB suspects, doing smear microscopy prior to Xpert assay in add-on fashion only identifies a few additional TB cases.

Understanding the interface between clinical and laboratory staff

BACKGROUND

The interface between clinicians and laboratory staff is where the two meet and work together to provide quality care to their clients (patients). Effectiveness of the interface depends on the way the two groups of professionals relate to and communicate with each other. The number and type of tests requested and the use of the test results for clinical decision making can be influenced by the interface between clinicians and laboratory staff. A model to understand the factors and dynamics around the interface is lacking.

OBJECTIVES

To propose a new conceptual model to gain insight and analyse factors that influence the laboratory-clinical staff interface.

METHODS

To develop the conceptual model, a literature study was performed, regulatory guidelines and standards for laboratories were analysed and discussions were held with experts on the topic.

RESULT

A conceptual model and analytical framework provided good guidance in understanding and assessing the organisational and personal factors shaping the interface. The model was based on three elements: (1) the three phases of communication (pre-analytical, analytical and post-analytical); (2) the organisational and personal factors of interaction; and (3) the socio-political, economic and cultural context in which clinicians and laboratory staff operate.

CONCLUSION

Assessment of the interface between clinicians and laboratory workers can be performed in a systematic way. Applying this model will provide information to managers of health institutions and heads of laboratories and clinical departments about what happens when clinicians and laboratory staff interact, thus aiding them in designing strategies to improve this interface.

The interface between clinicians and laboratory staff: A field study in northern Tanzania

BACKGROUND

Strengthening the communication and professional relationships between clinicians and laboratory workers is essential in order to positively change clinicians' attitudes about the reliability of diagnostic tests, enhancing the use of laboratory diagnostics and, ultimately, improving patient care. We developed an analytical framework to gain insight into the factors that influence communication amongst health professionals.

OBJECTIVE

To explore whether the interaction between clinicians and laboratory workers influences the use of laboratory test results in clinical decision making.

METHODS

Four health facilities in northern Tanzania were selected using convenience sampling, whereas study participants were selected using purposive sampling. The quantitative and qualitative data collection methods included self-administered questionnaires; semi-structured, individual interviews; in-depth, individual interviews; and/or focus group discussions with clinicians and laboratory workers. Thematic content analyses were performed on qualitative data based on the framework. Descriptive statistical analyses of quantitative data were conducted using Microsoft Excel.

RESULTS

Contact between clinicians and laboratory professionals is seldom institutionalised and collaboration is rare. The clinicians believe collaboration with laboratory staff is a challenge because of the gap in education levels. Laboratory workers' education levels are often lower than their positions require, leading to clinicians' lack of respect for and confidence in laboratory professionals, which compromises the laboratory staff's motivation.

CONCLUSIONS

Hospital managers, clinicians and laboratory workers need to recognise the critical and complementary roles each professional plays and the importance of addressing the gap between them. Field application of the framework proved successful, justifying the expansion of this study to a larger geographical area to include additional healthcare institutions.

Clinical evaluation of a low cost, in-house developed real-time RT-PCR human immunodeficiency virus type 1 (HIV-1) quantitation assay for HIV-1 infected patients

OBJECTIVES

HIV-1 viral quantitation is essential for treatment monitoring. An in-house assay would decrease financial barriers to access.

MATERIALS AND METHODS

A real-time competitive RT-PCR in house assay (Sing-IH) was developed in Singapore. Using HXB2 as reference, the assay's primers and probes were designed to generate a 183-bp product that overlaps a portion of the LTR region and gag region. A competitive internal control (IC) was included in each assay to monitor false negative results due to inhibition or human error. Clinical evaluation was performed on 249 HIV-1 positive patient samples in comparison with the commercially available Generic HIV Viral Load assay. Correlation and agreement of results were assessed for plasma HIV-1 quantification with both assays.

RESULTS

The assay has a lower limit of detection equivalent to 126 copies/mL of HIV-1 RNA and a linear range of detection from 100-1000000 copies/mL. Comparative analysis with reference to the Generic assay demonstrated good agreement between both assays with a mean difference of 0.22 log10 copies/mL and 98.8% of values within 1 log10 copies/mL range. Furthermore, the Sing-IH assay can quantify HIV-1 group M subtypes A-H and group N isolates adequately, making it highly suitable for our region, where subtype B and CRF01_AE predominate.

CONCLUSIONS

With a significantly lower running cost compared to commercially available assays, the broadly sensitive Sing-IH assay could help to overcome the cost barriers and serve as a useful addition to the currently limited HIV viral load assay options for resource-limited settings.

How PEPFAR's public-private partnerships achieved ambitious goals, from improving labs to strengthening supply chains

The President's Emergency Plan for AIDS Relief (PEPFAR), established in 2003, is widely recognized as one of the most ambitious and successful bilateral programs ever implemented to address a single disease. Part of the program's success is attributable to the participation of the private sector, working in partnership with the US and local governments and implementing organizations to maximize the reach and effectiveness of every dollar spent. We examined key public-private partnerships that grew out of PEPFAR to identify features that have made them effective. For example, PEPFAR's Supply Chain Management System took advantage of private industry's best practices in logistics, and a partnership with the medical technology company BD (Becton, Dickinson and Company) improved laboratory systems throughout sub-Saharan Africa. We found that setting ambitious goals, enlisting both global and local partners, cultivating a culture of collaboration, careful planning, continuous monitoring and evaluation, and measuring outcomes systematically led to the most effective programs. The Office of the US Global AIDS Coordinator and PEPFAR should continue to strengthen their capacity for private-sector partnerships, learning from a decade of experience and identifying new ways to make smart investments that will make the most efficient use of taxpayer resources, expand proven interventions more rapidly, and help ensure the sustainability of key programs.

Training laboratory technicians from the Ethiopian periphery in the MODS technique enables rapid and low-cost diagnosis of Mycobacterium tuberculosis infection

Tuberculosis (TB) is a leading cause of morbidity and mortality and is frequently complicated by emergence of drug-resistant strains. Diagnosis of TB in developing countries is often based on the relatively insensitive acid-fast staining that does not enable susceptibility profiling. Microscopic observation drug susceptibility assay (MODS) is an inexpensive, simple method that enables rapid TB culture coupled with susceptibility testing. A 3-week MODS training of three Ethiopian laboratory technicians was conducted at Hadassah-Hebrew University Medical Center, Israel. Results of the trainee readings were blindly assessed by an experienced instructor. Two hundred fifty-five (255) trainee culture readings were evaluated throughout the course. The sensitivity and specificity were 75-100% and 31.5-100%, respectively. Multivariate analysis revealed that sensitivity and duration of incubation were positively correlated, although specificity was positively correlated with the length of training. MODS can be reliably performed by laboratory technicians inexperienced in culture techniques in developing countries, with high sensitivity and specificity reached after a brief learning period.

Achieving universal access for human immunodeficiency virus and tuberculosis: potential prevention impact of an integrated multi-disease prevention campaign in kenya

In 2009, Government of Kenya with key stakeholders implemented an integrated multi-disease prevention campaign for water-borne diseases, malaria and HIV in Kisii District, Nyanza Province. The three day campaign, targeting 5000 people, included testing and counseling (HTC), condoms, long-lasting insecticide-treated bednets, and water filters. People with HIV were offered on-site CD4 cell counts, condoms, co-trimoxazole, and HIV clinic referral. We analysed the CD4 distributions from a district hospital cohort, campaign participants and from the 2007 Kenya Aids Indicator Survey (KAIS). Of the 5198 individuals participating in the campaign, all received HTC, 329 (6.3%) tested positive, and 255 (5%) were newly diagnosed (median CD4 cell count 536 cells/μL). The hospital cohort and KAIS results included 1,284 initial CD4 counts (median 348/L) and 306 initial CD4 counts (median 550/μL), respectively (campaign and KAIS CD4 distributions P = 0.346; hospital cohort distribution was lower P < 0.001 and P < 0.001). A Nyanza Province campaign strategy including ART <350 CD4 cell count could avert approximately 35,000 HIV infections and 1,240 TB cases annually. Community-based integrated public health campaigns could be a potential solution to reach universal access and Millennium Development Goals.

Evaluation of portable point-of-care CD4 counter with high sensitivity for detecting patients eligible for antiretroviral therapy

Background

Accurate, inexpensive point-of-care CD4+ T cell testing technologies are needed that can deliver CD4+ T cell results at lower level health centers or community outreach voluntary counseling and testing. We sought to evaluate a point-of-care CD4+ T cell counter, the Pima CD4 Test System, a portable, battery-operated bench-top instrument that is designed to use finger stick blood samples suitable for field use in conjunction with rapid HIV testing.

Methods

Duplicate measurements were performed on both capillary and venous samples using Pima CD4 analyzers, compared to the BD FACSCalibur (reference method). The mean bias was estimated by paired Student's t-test. Bland Altman plots were used to assess agreement.

Results

206 participants were enrolled with a median CD4 count of 396 (range; 18–1500). The finger stick PIMA had a mean bias of −66.3 cells/µL (95%CI −83.4−49.2, P<0.001) compared to the FACSCalibur; the bias was smaller at lower CD4 counts (0–250 cells/µL) with a mean bias of −10.8 (95%CI −27.3−+5.6, P = 0.198), and much greater at higher CD4 cell counts (>500 cells/µL) with a mean bias of −120.6 (95%CI −162.8, −78.4, P<0.001). The sensitivity (95%CI) of the Pima CD4 analyzer was 96.3% (79.1–99.8%) for a <250 cells/ul cut-off with a negative predictive value of 99.2% (95.1–99.9%).

Conclusions

The Pima CD4 finger stick test is an easy-to-use, portable, relatively fast device to test CD4+ T cell counts in the field. Issues of negatively-biased CD4 cell counts especially at higher absolute numbers will limit its utility for longitudinal immunologic response to ART. The high sensitivity and negative predictive value of the test makes it an attractive option for field use to identify patients eligible for ART, thus potentially reducing delays in linkage to care and ART initiation.

Prioritizing CD4 count monitoring in response to ART in resource-constrained settings: a retrospective application of prediction-based classification

BACKGROUND

Global programs of anti-HIV treatment depend on sustained laboratory capacity to assess treatment initiation thresholds and treatment response over time. Currently, there is no valid alternative to CD4 count testing for monitoring immunologic responses to treatment, but laboratory cost and capacity limit access to CD4 testing in resource-constrained settings. Thus, methods to prioritize patients for CD4 count testing could improve treatment monitoring by optimizing resource allocation.

METHODS AND FINDINGS

Using a prospective cohort of HIV-infected patients (n=1,956) monitored upon antiretroviral therapy initiation in seven clinical sites with distinct geographical and socio-economic settings, we retrospectively apply a novel prediction-based classification (PBC) modeling method. The model uses repeatedly measured biomarkers (white blood cell count and lymphocyte percent) to predict CD4(+) T cell outcome through first-stage modeling and subsequent classification based on clinically relevant thresholds (CD4(+) T cell count of 200 or 350 cells/µl). The algorithm correctly classified 90% (cross-validation estimate=91.5%, standard deviation [SD]=4.5%) of CD4 count measurements <200 cells/µl in the first year of follow-up; if laboratory testing is applied only to patients predicted to be below the 200-cells/µl threshold, we estimate a potential savings of 54.3% (SD=4.2%) in CD4 testing capacity. A capacity savings of 34% (SD=3.9%) is predicted using a CD4 threshold of 350 cells/µl. Similar results were obtained over the 3 y of follow-up available (n=619). Limitations include a need for future economic healthcare outcome analysis, a need for assessment of extensibility beyond the 3-y observation time, and the need to assign a false positive threshold.

CONCLUSIONS

Our results support the use of PBC modeling as a triage point at the laboratory, lessening the need for laboratory-based CD4(+) T cell count testing; implementation of this tool could help optimize the use of laboratory resources, directing CD4 testing towards higher-risk patients. However, further prospective studies and economic analyses are needed to demonstrate that the PBC model can be effectively applied in clinical settings. Please see later in the article for the Editors' Summary.

Measures of site resourcing predict virologic suppression, immunologic response and HIV disease progression following highly active antiretroviral therapy (HAART) in the TREAT Asia HIV Observational Database (TAHOD)

OBJECTIVES

Surrogate markers of HIV disease progression are HIV RNA in plasma viral load (VL) and CD4 cell count (immune function). Despite improved international access to antiretrovirals, surrogate marker diagnostics are not routinely available in resource-limited settings. Therefore, the objective was to assess effects of economic and diagnostic resourcing on patient treatment outcomes.

METHODS

Analyses were based on 2333 patients initiating highly active antiretroviral therapy (HAART) from 2000 onwards. Sites were categorized by World Bank country income criteria (high/low) and annual frequency of VL (> or = 3, 1-2 or <1) or CD4 (> or = 3 or <3) testing. Endpoints were time to AIDS/death and change in CD4 cell count and VL suppression (<400 HIV-1 RNA copies/mL) at 12 months. Demographics, Centers for Disease Control and Prevention (CDC) classification, baseline VL/CD4 cell counts, hepatitis B/C coinfections and HAART regimen were covariates. Time to AIDS/death was analysed by proportional hazards models. CD4 and VL endpoints were analysed using linear and logistic regression, respectively.

RESULTS

Increased disease progression was associated with site-reported VL testing less than once per year [hazard ratio (HR)=1.4; P=0.032], severely symptomatic HIV infection (HR=1.4; P=0.003) and hepatitis C virus coinfection (HR=1.8; P=0.011). A total of 1120 patients (48.2%) had change in CD4 cell count data. Smaller increases were associated with older age (P<0.001) and 'Other' HIV source exposures, including injecting drug use and blood products (P=0.043). A total of 785 patients (33.7%) contributed to the VL suppression analyses. Patients from sites with VL testing less than once per year [odds ratio (OR)=0.30; P<0.001] and reporting 'Other' HIV exposures experienced reduced suppression (OR=0.28; P<0.001).

CONCLUSION

Low measures of site resourcing were associated with less favourable patient outcomes, including a 35% increase in disease progression in patients from sites with VL testing less than once per year.

Hidden drug resistant HIV to emerge in the era of universal treatment access in Southeast Asia

BACKGROUND

Universal access to first-line antiretroviral therapy (ART) for HIV infection is becoming more of a reality in most low and middle income countries in Asia. However, second-line therapies are relatively scarce.

METHODS AND FINDINGS

We developed a mathematical model of an HIV epidemic in a Southeast Asian setting and used it to forecast the impact of treatment plans, without second-line options, on the potential degree of acquisition and transmission of drug resistant HIV strains. We show that after 10 years of universal treatment access, up to 20% of treatment-naïve individuals with HIV may have drug-resistant strains but it depends on the relative fitness of viral strains.

CONCLUSIONS

If viral load testing of people on ART is carried out on a yearly basis and virological failure leads to effective second-line therapy, then transmitted drug resistance could be reduced by 80%. Greater efforts are required for minimizing first-line failure, to detect virological failure earlier, and to procure access to second-line therapies.

Factors associated with self-reported adherence to antiretroviral therapy in a Tanzanian setting

This study aimed to determine the level of antiretroviral adherence and factors associated with adherence among patients receiving free antiretroviral therapy (ART) at one clinic in Tanzania. Adult patients were recruited into the cross-sectional study and completed a survey that included self-reported adherence over four days and over one month. Less than 95% adherence on either measure was considered "poor." Factors associated with adherence in unadjusted analyses (alpha = 0.10) were included in a logistic regression model. A total of 340 patients participated in the study, and 5.9% (20/340) reported poor adherence. The final model found poor adherence associated with: being young (odds ratio (OR) = 4.03) or old (OR = 6.68); having lower perceived quality of patient-provider interaction (OR = 2.75); and ever missing a clinic appointment (OR = 3.13). Results highlight good adherence, but suggest the importance of addressing: (1) age-specific challenges of adherence through counseling and support; (2) client-focused care and quality of patient-provider interaction; and (3) clinic appointment reminder systems.

Usefulness of the paralens fluorescent microscope adaptor for the identification of mycobacteria in both field and laboratory settings

The presence of acid-fast bacilli (AFB) in laboratories has traditionally been demonstrated using the fluorochrome method, which requires a fluorescent microscope or the Ziehl-Neelsen (ZN) method employing light microscopy. Low sensitivity of the ZN method and high costs of fluoroscopy make the need for a more effective means of diagnosis a top priority, especially in developing countries where the burden of tuberculosis is high. The QBC ParaLens™ attachment (QBC Diagnostic Inc., Port Matilda, PA) is a substitute for conventional fluoroscopy in the identification of AFB. To evaluate the efficacy of the ParaLens LED (light-emitting diode) system, the authors performed a two-part study, looking at usefulness, functionality and durability in urban/rural health clinics around the world, as well as in a controlled state public health laboratory setting. In the field, the ParaLens was durable and functioned well with various power sources and lighting conditions. Results from the state laboratory indicated agreement between standard fluorescent microscopy and fluorescent microscopy using the ParaLens. This adaptor is a welcome addition to laboratories in resource-limited settings as a useful alternative to conventional fluoroscopy for detection of mycobacterial species.

Advantages of peptide nucleic acids as diagnostic platforms for detection of nucleic acids in resource-limited settings

Peptide nucleic acids are a class of nondegradable oligonucleotide mimics that can be used as probes for nucleic acid sequences and could convey the necessary stability to be a diagnostic tool for use in a resource-limited setting. In this review, there is a brief introduction to the field of peptide nucleic acids and their potential benefits as probes for DNA and RNA sequences, followed by highlights of ways by which peptide nucleic acids could benefit a number of established diagnostic tools for human immunodeficiency virus detection.

Proteomic and metabolomic strategies to investigate HIV-associated neurocognitive disorders

Diagnosing neurodegenerative diseases, monitoring their progression and assessing responses to treatments will all be aided by the identification of molecular markers of different stages of pathology. Protein biomarkers for HIV-associated neurocognitive disorders that have been discovered using proteomics include complement C3, soluble superoxide dismutase and a prostaglandin synthase. Metabolomics has not yet been widely used for biomarker discovery, but early work shows that it has great potential.

Tuberculosis-associated immune reconstitution inflammatory syndrome and unmasking of tuberculosis by antiretroviral therapy

The tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is a frequent early complication of antiretroviral therapy (ART), used to treat HIV-1 infection, especially in countries where TB is prevalent. TB-IRIS is characterized by an exaggerated inflammatory response toward the antigens of Mycobacterium tuberculosis that results in clinical deterioration in patients experiencing immune recovery during early ART. Two forms of TB-IRIS are recognized: paradoxical; and unmasking. Paradoxical TB-IRIS manifests with new or recurrent TB symptoms or signs in patients being treated for TB during early ART, and unmasking TB-IRIS is characterized by an exaggerated, unusually inflammatory initial presentation of TB during early ART. In this review the incidence, clinical features, risk factors, treatment, and prevention of TB-IRIS in adult and pediatric patients are discussed.

HIV-1 neuroimmunity in the era of antiretroviral therapy

Human immunodeficiency virus type 1 (HIV-1)-associated neurocognitive disorders (HAND) can affect up to 50% of infected people during the disease course. While antiretroviral therapies have substantively increased the quality of life and reduced HIV-1-associated dementia, less severe minor cognitive and motor deficits continue. Trafficking of HIV-1 into the central nervous system (CNS), peripheral immune activation, dysregulated glial immunity, and diminished homeostatic responses are the disease-linked pathobiologic events. Monocyte-macrophage passage into the CNS remains an underlying force for disease severity. Monocyte phenotypes may change at an early stage of cell maturation and immune activation of hematopoietic stem cells. Activated monocytes are pulled into the brain in response to chemokines made as a result of glial inflammatory processes, which in turn, cause secondary functional deficits in neurons. Current therapeutic approaches are focused on adjunctive and brain-penetrating antiretroviral therapies. These may attenuate virus-associated neuroinflammatory activities thereby decreasing the severity and frequency of HAND.

Prevalence of Sexually Transmitted Diseases and Risk Behaviors from the NIMH Collaborative HIV/STD Prevention Trial

This cross-sectional study describes the baseline prevalence and correlates of common bacterial and viral sexually transmitted diseases (STDs) and risk behaviors among individuals at high risk for HIV recruited in five low- and middle-income countries. Correlations of risk behaviors and demographic factors with prevalent STDs and the association of STDs with HIV prevalence are examined. Between 2,212 and 5,543 participants were recruited in each of five countries (China, India, Peru, Russia, and Zimbabwe). Standard protocols were used to collect behavioral risk information and biological samples for STD testing. Risk factors for HIV/STD prevalence were evaluated using logistic regression models. STD prevalence was significantly higher for women than men in all countries, and the most prevalent STD was Herpes simplex virus-type 2 (HSV-2). HIV prevalence was generally low (below 5%) except in Zimbabwe (30% among women, 11.7% among men). Prevalence of bacterial STDs was generally low (below 5% for gonorrhea and under 7% for syphilis in all sites), with the exception of syphilis among female sex workers in India. Behavioral and demographic risks for STDs varied widely across the five study sites. Common risks for STDs included female gender, increasing number of recent sex partners, and in some sites, older age, particularly for chronic STDs (i.e., HSV-2 and HIV). Prevalence of HIV was not associated with STDs except in Zimbabwe, which showed a modest correlation between HIV and HSV-2 prevalence (Pearson coefficient = .55). These findings underscore the heterogeneity of global STD and HIV epidemics and suggest that local, focused interventions are needed to achieve significant declines in these infections.

Research needs and challenges in the development of HIV diagnostic and treatment monitoring tests for use in resource-limited settings

PURPOSE OF REVIEW

The aim of this article is to review research priorities for current and new technologies to diagnose HIV and to monitor treatment response, including technologies to enumerate CD4 cell counts and quantify plasma viral load, in resource-limited settings.

RECENT FINDINGS

Numerous challenges remain before HIV diagnostic and treatment monitoring technologies can be broadly implemented, especially in rural areas. New technologies that are less costly and complex to use are in development and may be better suited than current technologies for use in resource-limited settings. Investment into research activities is needed for development, evaluation and validation of new technologies. The lack of clarity in the process for evaluation and validation for these technologies affects country and program-level decisions on the appropriateness of technologies for individual settings. Implementation research is needed to assess how best to use CD4 and viral load to guide initiation and management of antiretroviral treatment, as well as how best to scale up diagnosis of HIV serostatus in infants. Studies also need to be conducted to determine if the same CD4 cutoffs can be used in resource-limited settings for initiating antiretroviral therapy and prophylaxis against opportunistic infections due to potential regional differences and the impact of other common co-morbidities on CD4 cell counts.

SUMMARY

Increased availability of antiretroviral therapy in resource-limited settings increases the need for reliable, less costly and simpler to use HIV diagnostic and treatment monitoring technologies. Global leadership is needed to coordinate the research and development necessary to ensure that HIV diagnostic and treatment monitoring technologies are properly evaluated in the setting where they will be used.

Public health requirements for rapid progress in global health

Effective public health interventions can save hundreds of millions of lives in developing countries, as well as create broad social and economic benefits. Unfortunately, public health approaches and solutions applied in developed countries are often assumed to be inappropriate or unattainable in developing countries. This has sometimes forestalled effective interventions in parts of the world where they are most needed, despite conditions that now facilitate lasting solutions to both long-standing and emerging global public health problems. Core public health functions are similar regardless of a country's income level. Although some resource-intensive approaches from industrialised nations are inappropriate in less developed countries, many basic public health measures achieved decades ago in developed countries are urgently needed, highly appropriate, extremely cost-effective and eminently attainable in developing countries today. About half of the disease burden in low and middle-income countries is now from non-communicable diseases, but non-communicable disease epidemics that will otherwise increase rapidly in the developing world can be avoided or reversed. Progress of public health in developing countries is possible, but will require sufficient funding and human resources; improved physical plant and information systems; effective programme implementation and regulatory capacity; and, most importantly, political will at the highest levels of government.

Multiplexed microbead immunoassays by flow cytometry for molecular profiling: Basic concepts and proteomics applications

Flow cytometry was originally established as an automated method for measuring optical or fluorescence characteristics of cells or particles in suspension. With the enormous increase in development of reliable electronics, lasers, micro-fluidics, as well as many advances in immunology and other fields, flow cytometers have become user-friendlier, less-expensive instruments with an increasing importance for both basic research and clinical applications. Conventional uses of flow cytometry include immunophenotyping of blood cells and the analysis of the cell cycle. Importantly, methods for labeling microbeads with unique combinations of fluorescent spectral signatures have made multiplex analysis of soluble analytes (i.e. the ability to detect multiple targets in a single test sample) feasible by flow cytometry. The result is a rapid, high-throughput, sensitive, and reproducible detection technology for a wide range of biomedical applications requiring detection of proteins (in cells and biofluids) and nucleic acids. Thus, novel methods of flow cytometry are becoming important for diagnostic purposes (e.g. identifying multiple clinical biomarkers for a wide range of diseases) as well as for developing novel therapies (e.g. elucidating drug mechanisms and potential toxicities). In addition, flow cytometry for multiplex analysis, coupled with automated sample handling devices, has the potential to significantly enhance proteomics research, particularly analysis of post-translational modifications of proteins, on a large scale. Inherently, flow cytometry methods are strongly rooted in the laws of the physics of optics, fluidics, and electromagnetism. This review article describes principles and early sources of flow cytometry, provides an introduction to the multiplex microbead technology, and discusses its applications and advantages in comparison to other methods. Anticipated future directions, particularly for translational research in medicine, are also discussed.

Surviving sepsis in low-income and middle-income countries: new directions for care and research

Sepsis is a disorder characterised by systemic inflammation secondary to infection. Despite recent progress in the understanding and treatment of sepsis, no data or recommendations exist that detail effective approaches to sepsis care in resource-limited low-income and middle-income countries (LMICs). Although few data exist on the burden of sepsis in LMICs, the prevalence of HIV and other comorbid conditions in some LMICs suggest that sepsis is a substantial contributor to mortality in these regions. In well-resourced countries, sepsis management relies on protocols and complex invasive technologies not widely available in most LMICs. However, the key concepts and components of sepsis management are potentially translatable to resource-limited environments. Health personnel in LMICs should be educated in the recognition of sepsis and the importance of early and appropriate antibiotic use. Simple and low-cost standardised laboratory testing should be emphasised to allow accurate diagnosis, prognosis, and monitoring of treatment response. Evidence-based interventions and treatment algorithms tailored to LMIC ecology and resources should thus be developed and validated.

"It's all the time in my mind": facilitators of adherence to antiretroviral therapy in a Tanzanian setting

Although HIV positive patients' adherence to antiretroviral therapy (ART) is relatively high in African nations, as compared with industrialized nations, few studies have explored why. In the research presented here we aimed to understand the dynamics of good adherence to ART among patients receiving free ART and HIV-related services from a clinic in Arusha, Tanzania. We conducted individual semi-structured interviews with 6 health care providers and 36 patients at a health care center in Arusha in 2006. Interviews were conducted in Swahili using interview guides informed by social cognitive theory. All interviews were audio-recorded, transcribed in Kiswahili, translated into English and coded for themes and patterns with ATLAS.ti. Of the 36 patients interviewed (mean time on ART 9.8 months; range 1-23 months), 32 reported perfect adherence in the previous month. Self-reported adherence was high despite economic hardship, depression, low rates of HIV disclosure and high perceived HIV-associated stigma. Five factors emerged to explain excellent adherence in the face of such barriers. First, all respondents experienced substantial improvements in their health after starting ART; this supported their confidence in the medication and motivated them to adhere. Second, their perceived need to be able to meet their family responsibilities motivated respondents to stay healthy. Third, respondents developed specific strategies to remember to take pills, particularly routinizing pill-taking by linking it with daily activities or events. Fourth, material and emotional support received from others facilitated adherence. Finally, respondents trusted the advice and instructions of their health care providers, who regularly emphasized adherence. The facilitating factors identified were consistent with the constructs of social cognitive theory and highlighted the importance of interventions that address multiple levels of influence on adherence.

Clinico-pathological discrepancies in the diagnosis of causes of maternal death in sub-Saharan Africa: retrospective analysis

BACKGROUND

Maternal mortality is a major public-health problem in developing countries. Extreme differences in maternal mortality rates between developed and developing countries indicate that most of these deaths are preventable. Most information on the causes of maternal death in these areas is based on clinical records and verbal autopsies. Clinical diagnostic errors may play a significant role in this problem and might also have major implications for the evaluation of current estimations of causes of maternal death.

METHODS AND FINDINGS

A retrospective analysis of clinico-pathologic correlation was carried out, using necropsy as the gold standard for diagnosis. All maternal autopsies (n = 139) during the period from October 2002 to December 2004 at the Maputo Central Hospital, Mozambique were included and major diagnostic discrepancies were analyzed (i.e., those involving the cause of death). Major diagnostic errors were detected in 56 (40.3%) maternal deaths. A high rate of false negative diagnoses was observed for infectious diseases, which showed sensitivities under 50%: HIV/AIDS-related conditions (33.3%), pyogenic bronchopneumonia (35.3%), pyogenic meningitis (40.0%), and puerperal septicemia (50.0%). Eclampsia, was the main source of false positive diagnoses, showing a low predictive positive value (42.9%).

CONCLUSIONS

Clinico-pathological discrepancies may have a significant impact on maternal mortality in sub-Saharan Africa and question the validity of reports based on clinical data or verbal autopsies. Increasing clinical awareness of the impact of obstetric and nonobstetric infections with their inclusion in the differential diagnosis, together with a thorough evaluation of cases clinically thought to be eclampsia, could have a significant impact on the reduction of maternal mortality.

Impact and cost-effectiveness of culture for diagnosis of tuberculosis in HIV-infected Brazilian adults

Background

Culture of Mycobacterium tuberculosis currently represents the closest “gold standard” for diagnosis of tuberculosis (TB), but operational data are scant on the impact and cost-effectiveness of TB culture for human immunodeficiency (HIV-) infected individuals in resource-limited settings.

Methodology/Principal Findings

We recorded costs, laboratory results, and dates of initiating TB therapy in a centralized TB culture program for HIV-infected patients in Rio de Janeiro, Brazil, constructing a decision-analysis model to estimate the incremental cost-effectiveness of TB culture from the perspective of a public-sector TB control program. Of 217 TB suspects presenting between January 2006 and March 2008, 33 (15%) had culture-confirmed active tuberculosis; 23 (70%) were smear-negative. Among smear-negative, culture-positive patients, 6 (26%) began TB therapy before culture results were available, 11 (48%) began TB therapy after culture result availability, and 6 (26%) did not begin TB therapy within 180 days of presentation. The cost per negative culture was US$17.52 (solid media)–$23.50 (liquid media). Per 1,000 TB suspects and compared with smear alone, TB culture with solid media would avert an estimated eight TB deaths (95% simulation interval [SI]: 4, 15) and 37 disability-adjusted life years (DALYs) (95% SI: 13, 76), at a cost of $36 (95% SI: $25, $50) per TB suspect or $962 (95% SI: $469, $2642) per DALY averted. Replacing solid media with automated liquid culture would avert one further death (95% SI: −1, 4) and eight DALYs (95% SI: −4, 23) at $2751 per DALY (95% SI: $680, dominated). The cost-effectiveness of TB culture was more sensitive to characteristics of the existing TB diagnostic system than to the accuracy or cost of TB culture.

Conclusions/Significance

TB culture is potentially effective and cost-effective for HIV-positive patients in resource-constrained settings. Reliable transmission of culture results to patients and integration with existing systems are essential.

The Status of HIV-1 Resistance to Antiretroviral drugs in Sub-Saharan Africa

Access to highly active antiretroviral therapy (HAART) for persons infected with HIV in sub-Saharan Africa has greatly improved over the past few years. However, data on long-term clinical outcomes of Africans receiving HAART, patterns of HIV resistance to antiretroviral drugs and implications of HIV type-1 (HIV-1) subtype diversity in Africa for resistance, are limited. In resource-limited settings, concerns have been raised that deficiencies in health systems could create the conditions for accelerated development of resistance. Coordinated surveillance systems are being established to assess the emergence of resistance and the factors associated with resistance development, and to create the possibility for adjusting treatment guidelines as necessary. The purpose of this report is to review the literature on HIV-1 resistance to antiretroviral drugs in sub-Saharan Africa, in relation to the drug regimens used in Africa, HIV-1 subtype diversity and overall prevalence of resistance. The report focuses on resistance associated with treatment, prevention of mother-to-child transmission and transmitted resistance. It also outlines priorities for public health action and research.