Estimated dates of detectable infection (EDDIs) as an improvement upon Fiebig staging for HIV infection dating.

Accurate methods for determining the duration of HIV infection at the individual level are valuable in many settings, including many critical research studies and in clinical practice (especially for acute infection). Since first published in 2003, the 'Fiebig staging system' has been used as the primary way of classifying early HIV infection into five sequential stages based on HIV test result patterns in newly diagnosed individuals. However, Fiebig stages can only be assigned to individuals who produce both a negative and a positive test result on the same day, on specific pairs of tests of varying 'sensitivity'. Further, in the past 16 years HIV-testing technology has evolved substantially, and three of the five key assays used to define Fiebig stages are no longer widely used. To address these limitations, we developed an improved and more general framework for estimating the duration of HIV infection by interpreting any combination of diagnostic test results, whether obtained on single or multiple days, into an estimated date of detectable infection, or EDDI. A key advantage of the EDDI method over Fiebig staging is that it allows for the generation of a point estimate, as well as an associated credibility interval for the date of first detectable infection, for any person who has at least one positive and one negative HIV test of any kind. The tests do not have to be run on the same day; they do not have to be run during the acute phase of infection and the method does not rely on any special pairing of tests to define 'stages' of infection. The size of the interval surrounding the EDDI (and therefore the precision of the estimate itself) depends largely on the length of time between negative and positive tests. The EDDI approach is also flexible, seamlessly incorporating any assay for which there is a reasonable diagnostic delay estimate. An open-source, free online tool includes a user-updatable curated database of published diagnostic delays. HIV diagnostics have evolved tremendously since that original publication more than 15 years ago, and it is time to similarly evolve the methods used to estimate timing of infection. The EDDI method is a flexible and rigorous way to estimate the timing of HIV infection in a continuously evolving diagnostic landscape.

Moving towards a reliable HIV incidence test - current status, resources available, future directions and challenges ahead.

In 2011 the Incidence Assay Critical Path Working Group reviewed the current state of HIV incidence assays and helped to determine a critical path to the introduction of an HIV incidence assay. At that time the Consortium for Evaluation and Performance of HIV Incidence Assays (CEPHIA) was formed to spur progress and raise standards among assay developers, scientists and laboratories involved in HIV incidence measurement and to structure and conduct a direct independent comparative evaluation of the performance of 10 existing HIV incidence assays, to be considered singly and in combinations as recent infection test algorithms. In this paper we report on a new framework for HIV incidence assay evaluation that has emerged from this effort over the past 5 years, which includes a preliminary target product profile for an incidence assay, a consensus around key performance metrics along with analytical tools and deployment of a standardized approach for incidence assay evaluation. The specimen panels for this evaluation have been collected in large volumes, characterized using a novel approach for infection dating rules and assembled into panels designed to assess the impact of important sources of measurement error with incidence assays such as viral subtype, elite host control of viraemia and antiretroviral treatment. We present the specific rationale for several of these innovations, and discuss important resources for assay developers and researchers that have recently become available. Finally, we summarize the key remaining steps on the path to development and implementation of reliable assays for monitoring HIV incidence at a population level.

Detectable HIV-1 RNA at levels below quantifiable limits by amplicor HIV-1 monitor is associated with virologic relapse on antiretroviral therapy.

OBJECTIVE: To assess the clinical significance of HIV-1 RNA levels detectable using the Amplicor HIV-1 Monitor method but < 400 copies/ml versus levels undetectable by this method. DESIGN: Retrospective cohort study. METHODS: All plasma HIV-1 RNA results over 13 months in our institution were reviewed. The study population comprised all individuals that achieved an HIV-1 RNA level < 400 copies/ml and remained on stable antiretroviral therapy. Results of < 400 copies/ml were stratified as 'below quantifiable limits' (BQL) or 'below detectable limits' (BDL). We examined the incidence of virologic relapse, defined as an HIV-1 RNA level > 400 copies/ml, for individuals with viral loads of BQL or BDL. Cox proportional hazards regression analyses were performed to control for baseline CD4 cell count, the number of antiretroviral medications, and the use of protease inhibitors (PI) and/or non-nucleoside reverse transcriptase inhibitors (NNRTI). RESULTS: Virologic relapse occurred in 52 of 168 individuals over 29,576 person-days overall (incidence rate 1.8 cases/1,000 person-days). The relapse rate was three times greater following HIV-1 RNA levels of BQL rather than BDL [crude rate ratio 3.2; 95% confidence interval (CI) 1.8-5.8]. After adjusting for baseline CD4 cell count, number of antiretroviral medications, and use of PI and/or NNRTI, the rate of relapse was nearly four times greater for individuals with HIV-1 RNA levels of BQL (hazard ratio 3.7; 95% CI 2.0-6.7). CONCLUSIONS: In a large clinic population, low-level HIV-1 RNA detected in plasma below the 400 copies/ml limit of quantifiability for Amplicor HIV-1 Monitor was associated with an increased rate of virologic relapse on therapy.

HIV in body fluids during primary HIV infection: implications for pathogenesis, treatment and public health.

OBJECTIVE: To describe initial viral dissemination to peripheral tissues and infectious body fluids during human primary HIV infection. DESIGN: Observational cohort study. METHODS: Blood plasma, cerebrospinal fluid (CSF), seminal plasma, cervicovaginal lavage fluid and/or saliva were sampled from 17 individuals with primary HIV infection (range of time from symptoms onset to sampling, 8--70 days) and one individual with early infection (168 days). Subjects' HIV-1 RNA levels in each fluid were compared with levels from antiretroviral-naive controls with established HIV infection. For study subjects, correlations were assessed between HIV-1 RNA levels and time from symptoms onset. Responses to antiretroviral therapy with didanosine + stavudine + nevirapine +/- hydroxyurea were assessed in each compartment. RESULTS: HIV-1 RNA levels were highest closest to symptoms onset in blood plasma (18 patients) and saliva (11 patients). CSF HIV-1 RNA levels (five patients) appeared lower closer to symptoms onset, although they were higher overall in primary versus established infection. Shedding into seminal plasma (eight patients) and cervicovaginal fluid (two patients) was established at levels observed in chronic infection within 3--5 weeks of symptoms onset. High-level seminal plasma shedding was associated with coinfection with other sexually transmitted pathogens. Virus replication was suppressed in all compartments by antiretroviral therapy. CONCLUSIONS: Peak level HIV replication is established in blood, oropharyngeal tissues and genital tract, but potentially not in CSF, by the time patients are commonly diagnosed with primary HIV infection. Antiretroviral therapy is unlikely to limit initial virus spread to most tissue compartments, but may control genital tract shedding and central nervous system expansion in primary infection.

Effect of planting dates and Bacillus thuringiensis corn on the population dynamics of European corn borer (Lepidoptera: Crambidae).

Field studies were conducted to determine how field corn, Zea mays L., phenologies in combination with transgenic Bacillus thuringiensis Berliner (Bt) corn and non-Bt (near isogenic) corn could affect egg laying by female European corn borer, Ostrinia nubilalis (Hubner), and subsequent larval injury. Transgenic Bt (events 176 and Bt11) and non-Bt corn was planted at three different times to assess the use of early- and late- planted Bt corn as a means for egg recruitment to these targeted planting dates. Plant growth stages, egg densities, and stalk tunneling was recorded at four locations in southwestern, central, and northern Iowa for three summers (1996-1998). No significant differences in egg densities were observed between Bt and non-Bt corn during the first and second generation for all three years. Significant differences did occur among planting dates. Between 50 and 100% of the eggs were laid in the early planting during the first generation. In addition, between 40 and 65% of the eggs were laid in the late planting for the second generation. Correlations between egg density and larval tunneling were inconsistent from year to year. Additional inconsistencies stemming from yearly phenological differences among sequential plantings and variable O. nubilalis populations increases the difficulty in recommending planting date adjustments as a practical management tool for European corn borer and Bt corn.

Comparison of NucliSens and Roche Monitor assays for quantitation of levels of human immunodeficiency virus type 1 RNA in plasma.

We compared the performance of Organon Teknika's NucliSens and Roche Diagnostic Systems' Monitor quantitative human immunodeficiency type 1 RNA assays. Both had similar linearity and sensitivity over most of the dynamic range of the assays, although the Monitor assay was superior at the low range of RNA values while the NucliSens assay was more consistent at higher RNA values. NucliSens generally showed less interassay variability.

Genotypic resistance and the treatment of HIV-1 infection in Espírito Santo, Brazil.

Before December 1997, in Espírito Santo, Brazil, combination antiretroviral therapy was used without routine virologic or immunologic monitoring. To examine consequences of therapy in this setting, clinical information, human immunodeficiency virus type 1 (HIV-1) RNA levels, CD4 cell counts, and protease and reverse transcriptase sequences were determined for consecutive HIV-1-infected outpatients. Of 48 treatment-naive individuals, 11 were started on therapy for HIV-related symptoms; however, 44 (92%) had an RNA level >20,000 copies/mL, a CD4 cell count <500/mm3, or symptoms. Eighteen (51%) of 35 patients on therapy had an RNA level >20,000 copies/mL. Nucleoside-resistance mutations were observed in 21 (68%) of 31 nucleoside-experienced subjects. Protease mutations necessary for high-level protease inhibitor (PI) resistance were present together with permissive mutations in 3 of 10 PI-experienced patients. Inability to identify high-risk individuals and to detect virologic failure may limit the effectiveness of antiretroviral drug programs and may promote the spread of drug resistance where virologic and immunologic monitoring are not available.