Challenges for rapid molecular HIV diagnostics

Label-free detection of synthetic, full genomic length HIV-1 RNA at the few-copy level

Oligonucleotide-functionalized graphene biosensors show immense promise for use as label-free point of care devices for detection of nucleic acid biomarkers at clinically relevant levels. Graphene-based nucleic acid sensors can be fabricated at low cost and have been shown to reach limits of detection in the attomolar range. Here we demonstrate devices functionalized with 22mer or 8omer DNA probes are capable of detecting full length genomic HIV-1 subtype B RNA, with a limit of detection below 1 aM in nuclease free water. We also show that these sensors are suitable for detection directly in Qiazol lysis reagent, again with a limit of detection below 1 aM for both 22mer and 8omer probes.

False reactive HIV-1 diagnostic test results in an individual from Kenya on multiple testing platforms-A case report

Background

Rapid diagnostic tests (RDT) are routinely used in screening for HIV infection. More complex diagnostic algorithms incorporating fourth-generation screening and confirmatory HIV-1/HIV-2 differentiation immunoassays (IA) may be used to confirm HIV infection. Co-infections and autoimmune diseases may lead to falsely reactive HIV diagnostic test results.

Case presentation

A Kenyan man with asymptomatic schistosomiasis and low risk factors for HIV infection demonstrated an inconsistent and discordant pattern of reactivity on HIV RDT, repeated reactivity on fourth-generation IA and positive at a single time-point for HIV-1 on the Geenius HIV1/HIV2 confirmatory assay during the course of a prospective cohort study with HIV repeat testing. The individual initiated antiretroviral therapy following HIV diagnosis. However, his bi-annual behavioral questionnaire suggested low-risk factors for infection. Supplementary confirmatory serologic and nucleic acid tests were performed and gave discordant results. The participant was determined to be HIV uninfected using cell-associated HIV-1 DNA/RNA testing and antiretroviral therapy was discontinued.

Discussion and conclusions

Sole reliance on diagnostic test results may result in misdiagnosis of HIV infection, social harm and potential antiretroviral induced drug toxicity. Interpretation of HIV test results should incorporate multiple parameters.

The potential for quality assurance systems to save costs and lives: the case of early infant diagnosis of HIV

OBJECTIVES

Scaling up of point-of-care testing (POCT) for early infant diagnosis of HIV (EID) could reduce the large gap in infant testing. However, suboptimal POCT EID could have limited impact and potentially high avoidable costs. This study models the cost-effectiveness of a quality assurance system to address testing performance and screening interruptions, due to, for example, supply stockouts, in Kenya, Senegal, South Africa, Uganda and Zimbabwe, with varying HIV epidemics and different health systems.

METHODS

We modelled a quality assurance system-raised EID quality from suboptimal levels: that is, from misdiagnosis rates of 5%, 10% and 20% and EID testing interruptions in months, to uninterrupted optimal performance (98.5% sensitivity, 99.9% specificity). For each country, we estimated the 1-year impact and cost-effectiveness (US$/DALY averted) of improved scenarios in averting missed HIV infections and unneeded HIV treatment costs for false-positive diagnoses.

RESULTS

The modelled 1-year costs of a national POCT quality assurance system range from US$ 69 359 in South Africa to US$ 334 341 in Zimbabwe. At the country level, quality assurance systems could potentially avert between 36 and 711 missed infections (i.e. false negatives) per year and unneeded treatment costs between US$ 5808 and US$ 739 030.

CONCLUSIONS

The model estimates adding effective quality assurance systems are cost-saving in four of the five countries within the first year. Starting EQA requires an initial investment but will provide a positive return on investment within five years by averting the costs of misdiagnoses and would be even more efficient if implemented across multiple applications of POCT.

Evolution of Biochip Technology: A Review from Lab-on-a-Chip to Organ-on-a-Chip

Following the advancements in microfluidics and lab-on-a-chip (LOC) technologies, a novel biomedical application for microfluidic based devices has emerged in recent years and microengineered cell culture platforms have been created. These micro-devices, known as organ-on-a-chip (OOC) platforms mimic the in vivo like microenvironment of living organs and offer more physiologically relevant in vitro models of human organs. Consequently, the concept of OOC has gained great attention from researchers in the field worldwide to offer powerful tools for biomedical researches including disease modeling, drug development, etc. This review highlights the background of biochip development. Herein, we focus on applications of LOC devices as a versatile tool for POC applications. We also review current progress in OOC platforms towards body-on-a-chip, and we provide concluding remarks and future perspectives for OOC platforms for POC applications.

Frugal Innovation for Point-of-Care Diagnostics Controlling Outbreaks and Epidemics

Today epidemics of infectious diseases occur more often and spread both faster and further due to globalization and changes in our lifestyle. One way to meet these biological threats are so-called "Frugal Innovations", which focus on the development of affordable, rapid, and easy-to-use diagnostics with widespread use. In this context, point-of-care-tests (POCTs), performed at the patient's bedside, reduce extensive waiting times and unnecessary treatments and enable effective containment measures. This Perspective covers advances in POCT diagnostics on the basis of frugal innovation characteristics that will enable a faster, less expensive, and more convenient reaction to upcoming epidemics. Established POCT systems on the health care market, as well as currently evolving technological advancements in that sector are discussed. Progress in POCT technology and insights on how to most effectively use them allows the handling of more patients in a shorter time frame and consequently improves clinical outcomes at lower cost.

HIV Detection via a Carbon Nanotube RNA Sensor

Viral illnesses remain a significant concern in global health. Rapid and quantitative early detection of viral oligonucleotides without the need for purification, amplification, or labeling would be valuable in guiding successful treatment strategies. Single-walled carbon nanotube-based sensors recently demonstrated optical detection of small, free oligonucleotides in biofluids and in vivo, although proteins diminished sensitivity. Here, we discovered an unexpected phenomenon wherein the carbon nanotube optical response to nucleic acids can be enhanced by denatured proteins. Mechanistic studies found that hydrophobic patches of the denatured protein chain interact with the freed nanotube surface after hybridization, resulting in enhanced shifting of the nanotube emission. We employed this mechanism to detect an intact HIV in serum, resulting in specific responses within minutes. This work portends a route toward point-of-care optical detection of viruses or other nucleic acid-based analytes.

A multiplexed RT-LAMP assay for detection of group M HIV-1 in plasma or whole blood

Isothermal nucleic acid amplification techniques, such as reverse-transcription loop-mediated isothermal amplification (RT-LAMP), exhibit characteristics that are suitable for the development of a rapid, low-cost NAT that can be used at the POC. For demonstration of utility for global use, studies are needed to validate the performance of RT-LAMP for the detection of divergent subtypes. In this study, we designed and evaluated multiplexed HIV-1 integrase RT-LAMP primers to detect subtypes within group M, along with an RNase P positive internal processing and amplification control. Using a panel of 26 viral isolates representing the major circulating subtypes, we demonstrated detection of all isolates of subtypes A1, C, D, F1, F2, G, CRF01_AE, CRF02_AG, and two unique recombinant forms (URFs). A whole blood panel created with one representative isolate of each subtype was successfully amplified with the group M HIV-1 integrase and RNase P internal control primers. The group M HIV-1 RT-LAMP assay was further evaluated on 61 plasma specimens obtained from persons from Cameroon and Uganda. The sequence-conserved group M HIV-1 RT-LAMP primers, coupled to a low-cost amplification device, may improve diagnosis of acute infection at the POC and provide timely confirmation of HIV status.

Field evaluation of HIV point-of-care testing for early infant diagnosis in Cape Town, South Africa

Background

Early infant HIV diagnosis (EID) coverage and uptake remains challenging. Point-of-care (POC) testing may improve access and turn-around-times, but, while several POC technologies are in development there are few data on their implementation in the field.

Methods

We conducted an implementation study of the Alere q Detect POC system for EID at two public sector health facilities in Cape Town. HIV-exposed neonates undergoing routine EID testing at a large maternity hospital and a primary care clinic received both laboratory-based HIV PCR testing per local protocols and a POC test. We analysed the performance of POC versus laboratory testing, and conducted semi-structured interviews with providers to assess acceptability and implementation issues.

Results

Overall 478 specimens were taken: 311 tests were performed at the obstetric hospital (median child age, 1 days) and 167 six-week tests in primary care (median child age, 42 days). 9.0% of all tests resulted in an error with no differences by site; most errors resolved with retesting. POC was more sensitive (100%; lower 95% CI, 39.8%) and specific (100%, lower 95% CI, 98%) among older children tested in primary care compared with birth testing in hospital (90.0%, 95% CI, 55.5–99.8% and 100.0%, lower 95% CI, 98.4%, respectively). Negative predictive value was high (>99%) at both sites. In interviews, providers felt the device was simple to use and facilitated decision-making in the management of infants. However, many wanted clarity on the cause of errors on the POC device to help guide repeat testing.

Conclusions

POC EID testing performs well in field implementation in health care facilities and appears highly acceptable to health care providers.

Identification of HIV Mutation as Diagnostic Biomarker through Next Generation Sequencing

INTRODUCTION

Current clinical detection of Human immunodeficiency virus 1 (HIV-1) is used to target viral genes and proteins. However, the immunoassay, such as viral culture or Polymerase Chain Reaction (PCR), lacks accuracy in the diagnosis, as these conventional assays rely on the stable genome and HIV-1 is a highly-mutated virus. Next generation sequencing (NGS) promises to be transformative for the practice of infectious disease, and the rapidly reducing cost and processing time mean that this will become a feasible technology in diagnostic and research laboratories in the near future. The technology offers the superior sensitivity to detect the pathogenic viruses, including unknown and unexpected strains.

AIM

To leverage the NGS technology in order to improve current HIV-1 diagnosis and genotyping methods.

MATERIALS AND METHODS

Ten blood samples were collected from HIV-1 infected patients which were diagnosed by RT PCR at Singapore Communicable Disease Centre, Tan Tock Seng Hospital from October 2014 to March 2015. Viral RNAs were extracted from blood plasma and reversed into cDNA. The HIV-1 cDNA samples were cleaned up using a PCR purification kit and the sequencing library was prepared and identified through MiSeq.

RESULTS

Two common mutations were observed in all ten samples. The common mutations were identified at genome locations 1908 and 2104 as missense and silent mutations respectively, conferring S37N and S3S found on aspartic protease and reverse transcriptase subunits.

CONCLUSION

The common mutations identified in this study were not previously reported, therefore suggesting the potential for them to be used for identification of viral infection, disease transmission and drug resistance. This was especially the case for, missense mutation S37N which could cause an amino acid change in viral proteases thus reducing the binding affinity of some protease inhibitors. Thus, the unique common mutations identified in this study could be used as diagnostic biomarkers to indicate the origin of infection as being from Singapore.

Viral glycoproteins: biological role and application in diagnosis

The viruses that infect humans cause a huge global disease burden and produce immense challenge towards healthcare system. Glycoproteins are one of the major components of human pathogenic viruses. They have been demonstrated to have important role(s) in infection and immunity. Concomitantly high titres of antibodies against these antigenic viral glycoproteins have paved the way for development of novel diagnostics. Availability of appropriate biomarkers is necessary for advance diagnosis of infectious diseases especially in case of outbreaks. As human mobilization has increased manifold nowadays, dissemination of infectious agents became quicker that paves the need of rapid diagnostic system. In case of viral infection it is an emergency as virus spreads and mutates very fast. This review encircles the vast arena of viral glycoproteins, their importance in health and disease and their diagnostic applications.

Barriers to Implementation of Rapid and Point-of-Care Tests for Human Immunodeficiency Virus Infection: Findings From a Systematic Review (1996-2014)

Implementation of human immunodeficiency virus rapid and point-of-care tests (RDT/POCT) is understood to be impeded by many different factors that operate at 4 main levels-test devices, patients, providers, and health systems-yet a knowledge gap exists of how they act and interact to impede implementation. To fill this gap, and with a view to improving the quality of implementation, we conducted a systematic review.

METHODS

Five databases were searched, 16,672 citations were retrieved, and data were abstracted on 132 studies by 2 reviewers.

FINDINGS

Across 3 levels (ie, patients, providers, and health systems), a majority (59%, 112/190) of the 190 barriers were related to the integration of RDT/POCT, followed by test-device-related concern (ie, accuracy) at 41% (78/190). At the patient level, a lack of awareness about tests (15/54, 28%) and time taken to test (12/54, 22%) dominated. At the provider and health system levels, integration of RDT/POCT in clinical workflows (7/24, 29%) and within hospitals (21/34, 62%) prevailed. Accuracy (57/78, 73%) was dominant only at the device level.

INTERPRETATION

Integration barriers dominated the findings followed by test accuracy. Although accuracy has improved during the years, an ideal implementation could be achieved by improving the integration of RDT/POCT within clinics, hospitals, and health systems, with clear protocols, training on quality assurance and control, clear communication, and linkage plans to improve health outcomes of patients. This finding is pertinent for a future envisioned implementation and global scale-up of RDT/POCT-based initiatives.

Detection of Acute HIV-1 Infection by RT-LAMP

A rapid, cost-effective diagnostic test for the detection of acute HIV-1 infection is highly desired. Isothermal amplification techniques, such as reverse-transcription loop-mediated isothermal amplification (RT-LAMP), exhibit characteristics that are ideal for the development of a rapid nucleic acid amplification test (NAAT) because they are quick, easy to perform and do not require complex, dedicated equipment and laboratory space. In this study, we assessed the ability of the HIV-1 RT-LAMP assay to detect acute HIV infection as compared to a representative rapid antibody test and several FDA-approved laboratory-based assays. The HIV-1 RT-LAMP assay detected seroconverting individuals one to three weeks earlier than a rapid HIV antibody test and up to two weeks earlier than a lab-based antigen/antibody (Ag/Ab) combo enzyme immunoassay (EIA). RT-LAMP was not as sensitive as a lab-based qualitative RNA assay, which could be attributed to the significantly smaller nucleic acid input volume. To our knowledge, this is the first demonstration of detecting acute HIV infection using the RT-LAMP assay. The availability of a rapid NAAT, such as the HIV-1 RT-LAMP assay, at the point of care (POC) or in laboratories that do not have access to large platform NAAT could increase the percentage of individuals who receive an acute HIV infection status or confirmation of their HIV status, while immediately linking them to counseling and medical care. In addition, early knowledge of HIV status could lead to reduced high-risk behavior at a time when individuals are at a higher risk for transmitting the virus.

Performance of a parallel diagnostic algorithm for HIV diagnosis in low risk pediatric and obstetric patient populations

BACKGROUND

Little is known about the clinical performance of the 2010 APHL/CDC Western-blot independent HIV testing algorithm in low risk pediatric and obstetric patients.

OBJECTIVE

To evaluate the performance of an alternate Western-blot independent algorithm and the individual algorithm components in diagnosing HIV infections in low risk pediatric and obstetric patients.

STUDY DESIGN

6242 specimens from pediatric and obstetric patients were tested by the Bio-Rad Multispot HIV-1/HIV-2 (MS) and VITROS Anti HIV 1+2 (VITROS) assays. 913 specimens were also tested by the ARCHITECT HIV Ag/Ab Combo assay (ARCHITECT). Discordant specimens were tested by the APTIMA HIV-1 RNA qualitative assay (RNA Qual).

RESULTS

Twenty-eight specimens tested positive for HIV-1 by both MS and VITROS, 4 of these 28 specimens were also tested by and positive by ARCHITECT; all 28 positives identified by the algorithm were positive by viral load analysis. MS identified 164 preliminary positives, which were not confirmed as true positives, representing a specificity of 97.4%. This specificity varied between patient populations (96.1% in the pediatric population and 99.1% in the obstetric population). The specificities of VITROS and ARCHITECT were 99.2% and 99.4% for pediatric patients; 99.7% and 99.8% for obstetric patients, respectively.

CONCLUSION

Our results highlight suboptimal specificity of MS in pediatric patients, and a lower specificity in both pediatric and obstetric patients relative to either VITROS or ARCHITECT. Additionally, parallel testing with both a third and fourth generation EIA in a low risk patient population provides a potential alternative to Western-blot dependent algorithms for confirmation.

Clinical versus rapid molecular HIV diagnosis in hospitalized African infants: a randomized controlled trial simulating point-of-care infant testing

OBJECTIVE

Many African infants fail to receive their diagnostic HIV molecular test results and subsequently, antiretroviral therapy (ART). To determine whether a point-of-care molecular HIV test increases ART access for hospitalized Malawian infants, we simulated a point-of-care test using rapid HIV RNA polymerase chain reaction (Rapid PCR) and compared patient outcomes with an optimized standard care that included assessment with the World Health Organization clinical algorithm for HIV infection plus a DNA PCR with a turnaround time of several weeks (standard care).

DESIGN

Randomized controlled trial.

METHODS

Hospitalized HIV-exposed Malawian infants aged <12 months were randomized into Rapid PCR or standard care. Rapid PCR infants obtained molecular test results within 48 hours to facilitate immediate ART, similar to a point-of-care test. Standard care infants meeting clinical criteria were also offered inpatient ART. The primary outcome was appropriate in-hospital ART for DNA or RNA PCR-confirmed HIV-infected infants.

RESULTS

Three hundred infants were enrolled. A greater proportion of HIV-infected infants receiving Rapid PCR, versus standard care, started inpatient ART (72.3% vs 47.8%, P = 0.016). Among molecular test-negative infants, 26.9% receiving standard care unnecessarily initiated inpatient ART, versus 0.0% receiving Rapid PCR (P < 0.001). Rapid PCR modestly reduced the median days to ART (3.0 vs 6.5, P = 0.001) but did not influence outpatient follow-up for HIV-infected infants (78.1% vs 82.4%, P = 0.418).

CONCLUSIONS

Rapid PCR, versus an optimized standard care, increased the proportion of hospitalized HIV-infected infants initiating ART and reduced ART exposure in molecular test-negative infants, without meaningfully impacting time to ART initiation or follow-up rates.

Point of Care Technologies for HIV

Effective prevention of HIV/AIDS requires early diagnosis, initiation of therapy, and regular plasma viral load monitoring of the infected individual. In addition, incidence estimation using accurate and sensitive assays is needed to facilitate HIV prevention efforts in the public health setting. Therefore, more affordable and accessible point-of-care (POC) technologies capable of providing early diagnosis, HIV viral load measurements, and CD4 counts in settings where HIV is most prevalent are needed to enable appropriate intervention strategies and ultimately stop transmission of the virus within these populations to achieve the future goal of an AIDS-free generation. This review discusses the available and emerging POC technologies for future application to these unmet public health needs.

Integrated heaters for temperature control in disposable bioassay cartridges for use with portable, battery-operated instruments

Two methods for heating fluids in microliter- to milliliter-scale reaction chambers in disposable bioassay cartridges are analyzed and compared. Inductive heating requires no electrical contact between the energy source and the cartridge and uses a very inexpensive component in the cartridge. Resistive heating with a surface mount component requires electrical interconnection, but is generally conducive to low-cost off-the-shelf components. Typical power consumption for both inductive heating and resistive heating is consistent with battery-powered operation. A finite element model for heating an injection-molded plastic cartridge with a surface-mount resistor has been developed and validated through experiments on a 40 mm × 10 mm × 7.5 mm injection molded polystyrene cartridge with embedded 1 kΩ surface-mount resistors. A model of frequency-dependent heat generation in a novel inductive heating device is also presented.

HIV testing in developing countries: what is required?

HIV diagnostic and follow up testing are usually done in laboratory settings. However, in developing countries there is a need to decentralize testing as the majority of the population lives in rural settings. In developing countries stringent quality assurance (QA) practices, which include appropriate training, development of standard operating procedures, maintenance of operator proficiency, routine use of quality control (QC) specimens, standardized data management, equipment calibration and maintenance, and biohazard safety with proper disinfection/disposal procedures are not routinely followed to ensure reliability of results and a safe work environment. The introduction of point-of-care testing technologies involving the use of non-laboratorians in routine testing has further increased the complexity of QA. Therefore, a careful approach towards improvement of laboratories that encourages best practices, coupled with incentives, and review of government policies in point-of-care testing is needed to improve quality of testing as decentralization takes place. Development of a functional laboratory tiered network that facilitates communication, referral, training and problem solving could further enhance confidence in laboratory testing. There is also a need for special considerations in implementing a step-wise approach towards quality improvement, strengthening of the supply chain management, human capacity development, infrastructure upgrade, and strong public private partnerships to ensure long term sustainability of these efforts.

Testing for acute HIV infection: implications for treatment as prevention

PURPOSE OF REVIEW

The aim of this study is to give an overview of the recent literature related to HIV testing with an emphasis on detecting acute HIV infection. Testing technology as well as implications for treatment as prevention will be discussed.

RECENT FINDINGS

HIV testing technology continues to evolve. Advances include updated immunologic formats that detect both HIV antibody and antigen (4th generation assays), new nucleic acid amplification tests, and continued development of rapid assays that can be used in either clinical or nonclinical settings. Because of these advances there are proposed changes for HIV diagnostic algorithms to encourage detection of acute infection. These technologic advances have implications for HIV prevention as testing is a cornerstone for all HIV prevention strategies. There is considerable new research indicating that treatment may be an important aspect of HIV prevention. Data also suggest that detection of acute infection will be important for the success of these prevention strategies.

SUMMARY

Continued improvements in technology and testing practice are vital for the success of HIV prevention. Detection of acute or early HIV infection will likely play a key role in the success of treatment as prevention, as well as play an important role in ongoing behavioral prevention strategies.

Opportunities and challenges for cost-efficient implementation of new point-of-care diagnostics for HIV and tuberculosis

Stakeholders agree that supporting high-quality diagnostics is essential if we are to continue to make strides in the fight against human immunodeficiency virus (HIV) and tuberculosis. Despite the need to strengthen existing laboratory infrastructure, which includes expanding and developing new laboratories, there are clear diagnostic needs where conventional laboratory support is insufficient. Regarding HIV, rapid point-of-care (POC) testing for initial HIV diagnosis has been successful, but several needs remain. For tuberculosis, several new diagnostic tests have recently been endorsed by the World Health Organization, but a POC test remains elusive. Human immunodeficiency virus and tuberculosis are coendemic in many high prevalence locations, making parallel diagnosis of these conditions an important consideration. Despite its clear advantages, POC testing has important limitations, and laboratory-based testing will continue to be an important component of future diagnostic networks. Ideally, a strategic deployment plan should be used to define where and how POC technologies can be most efficiently and cost effectively integrated into diagnostic algorithms and existing test networks prior to widespread scale-up. In this fashion, the global community can best harness the tremendous capacity of novel diagnostics in fighting these 2 scourges.

Perspectives on introduction and implementation of new point-of-care diagnostic tests

In recent years, there has been significant investment from both the private and public sectors in the development of diagnostic technologies to meet the need for human immunodeficiency virus (HIV) and tuberculosis testing in low-resource settings. Future investments should ensure that the most appropriate technologies are adopted in settings where they will have a sustainable impact. Achieving these aims requires the involvement of many stakeholders, as their needs, operational constraints, and priorities are often distinct. Here, we discuss these considerations from different perspectives representing those of various stakeholders involved in the development, introduction, and implementation of diagnostic tests. We also discuss some opportunities to address these considerations.

Isothermal amplification using a chemical heating device for point-of-care detection of HIV-1

Background

To date, the use of traditional nucleic acid amplification tests (NAAT) for detection of HIV-1 DNA or RNA has been restricted to laboratory settings due to time, equipment, and technical expertise requirements. The availability of a rapid NAAT with applicability for resource-limited or point-of-care (POC) settings would fill a great need in HIV diagnostics, allowing for timely diagnosis or confirmation of infection status, as well as facilitating the diagnosis of acute infection, screening and evaluation of infants born to HIV-infected mothers. Isothermal amplification methods, such as reverse-transcription, loop-mediated isothermal amplification (RT-LAMP), exhibit characteristics that are ideal for POC settings, since they are typically quicker, easier to perform, and allow for integration into low-tech, portable heating devices.

Methodology/Significant Findings

In this study, we evaluated the HIV-1 RT-LAMP assay using portable, non-instrumented nucleic acid amplification (NINA) heating devices that generate heat from the exothermic reaction of calcium oxide and water. The NINA heating devices exhibited stable temperatures throughout the amplification reaction and consistent amplification results between three separate devices and a thermalcycler. The performance of the NINA heaters was validated using whole blood specimens from HIV-1 infected patients.

Conclusion

The RT-LAMP isothermal amplification method used in conjunction with a chemical heating device provides a portable, rapid and robust NAAT platform that has the potential to facilitate HIV-1 testing in resource-limited settings and POC.

Temporal changes in HCV genotype distribution in three different high risk populations in San Francisco, California

Background

Hepatitis C virus (HCV) genotype (GT) has become an important measure in the diagnosis and monitoring of HCV infection treatment. In the United States (U.S.) HCV GT 1 is reported as the most common infecting GT among chronically infected patients. In Europe, however, recent studies have suggested that the epidemiology of HCV GTs is changing.

Methods

We assessed HCV GT distribution in 460 patients from three HCV-infected high risk populations in San Francisco, and examined patterns by birth cohort to assess temporal trends. Multiple logistic regression was used to assess factors independently associated with GT 1 infection compared to other GTs (2, 3, and 4).

Results

Overall, GT 1 was predominant (72.4%), however younger injection drug users (IDU) had a lower proportion of GT 1 infections (54.7%) compared to older IDU and HIV-infected patients (80.5% and 76.6%, respectively). Analysis by birth cohort showed increasing proportions of non-GT 1 infections associated with year of birth: birth before 1970 was independently associated with higher adjusted odds of GT 1: AOR 2.03 (95% CI: 1.23, 3.34). African-Americans as compared to whites also had higher adjusted odds of GT 1 infection (AOR: 3.37; 95% CI: 1.89, 5.99).

Conclusions

Although, HCV GT 1 remains the most prevalent GT, especially among older groups, changes in GT distribution could have significant implications for how HCV might be controlled on a population level and treated on an individual level.

Most adults seek urgent healthcare when acquiring HIV-1 and are frequently treated for malaria in coastal Kenya

BACKGROUND

Acute HIV-1 infection (AHI) may present with symptoms for which urgent healthcare is sought. However, little is known about healthcare seeking around the time of HIV-1 seroconversion in sub-Saharan Africa.

METHODS

Review of clinical, counselling, treatment and laboratory records of previously HIV-1 seronegative at-risk adults, followed at monthly or 3-monthly visits, who seroconverted and enrolled in an AHI cohort. All HIV-seronegative plasma samples were tested for p24 antigen (p24) and stored preseroconversion samples for HIV-1 RNA (RNA). Factors associated with malaria treatment while acquiring HIV-1 were evaluated in multiple logistic regression.

RESULTS

Sixty men and 12 women (95% of 75 seroconverters) were evaluated, including 43 (60%) with either p24-positive or RNA-positive or HIV-1 discordant rapid antibodies prior to seroconversion. Prior to diagnosis, 54 patients (75%) reported fever and 50 (69%) sought urgent care for symptomatic illness, including 23 (32%) who sought care in a nonresearch setting. Twenty-nine patients (40%) received presumptive malaria treatment. Only 24% of febrile patients were tested for malaria parasites. All documented smear results were negative. Malaria treatment was strongly associated with fever [adjusted odds ratio (aOR): 46, 95% confidence interval (CI): 3-725] and nonresearch setting (aOR: 5, 95% CI: 3-64). AHI was suspected in six (12%) patients who presented for urgent care during research evaluation.

CONCLUSIONS

The majority of adults with AHI seek urgent healthcare. These individuals are often presumptively treated for malaria. Improved recognition of AHI in adults presenting for care may offer opportunities for optimizing HIV prevention strategies.

Cost analysis of centralized viral load testing for antiretroviral therapy monitoring in Nicaragua, a low-HIV prevalence, low-resource setting

Background

HIV viral load testing as a component of antiretroviral therapy monitoring is costly. Understanding the full costs and the major sources of inefficiency associated with viral load testing is critical for optimizing the systems and technologies that support the testing process. The objective of our study was to estimate the costs associated with viral load testing performed for antiretroviral therapy monitoring to both patients and the public healthcare system in a low-HIV prevalence, low-resource country.

Methods

A detailed cost analysis was performed to understand the costs involved in each step of performing a viral load test in Nicaragua, from initial specimen collection to communication of the test results to each patient's healthcare provider. Data were compiled and cross referenced from multiple information sources: laboratory records, regional surveillance centre records, and scheduled interviews with the key healthcare providers responsible for HIV patient care in five regions of the country.

Results

The total average cost of performing a viral load test in Nicaragua varied by region, ranging from US$99.01 to US$124.58, the majority of which was at the laboratory level: $88.73 to $97.15 per specimen, depending on batch size. The average cost to clinics at which specimens were collected ranged from $3.31 to $20.92, depending on the region. The average cost per patient for transportation, food, lodging and lost income ranged from $3.70 to $14.93.

Conclusions

The quantitative viral load test remains the single most expensive component of the process. For the patient, the distance of his or her residence from the specimen collection site is a large determinant of cost. Importantly, the efficiency of results reporting has a large impact on the cost per result delivered to the clinician and utility of the result for patient monitoring. Detailed cost analysis can identify opportunities for removing barriers to effective antiretroviral therapy monitoring programmes in limited-resource countries with low HIV prevalence.

Point-of-care tests for diagnosing infections in the developing world

Infectious diseases continue to cause an enormous burden of death and disability in developing countries. Increasing access to appropriate treatment for infectious diseases could have a major impact on disease burden. Some common infections can be managed syndromically without the need for diagnostic tests, but this is not appropriate for many infectious diseases, in which a positive diagnostic test is needed before treatment can be given. Since many people in developing countries do not have access to laboratory services, diagnosis depends on the availability of point of care (POC) tests. Historically there has been little investment in POC tests for diseases that are common in developing countries, but that is now changing. Lack of regulation of diagnostic tests in many countries has resulted in the widespread use of sub-standard POC tests, especially for malaria, making it difficult for manufacturers of reliable POC tests to compete. In recent years increased investment, technological advances, and greater awareness about the importance of reliable diagnostic tests has resulted in rapid progress. Rapid, reliable and affordable POC tests, requiring no equipment and minimal training, are now available for HIV infection, syphilis and malaria, but POC tests for other infections are urgently needed. Many countries do not have established criteria for licensing and introducing new diagnostic tests, and many clinicians in developing countries have become disillusioned with diagnostic tests and prefer to rely on clinical judgment. Continuing advocacy and training in the use of POC tests are needed, and systems for quality control of POC tests need to be developed if they are to achieve their maximum potential.