Antiretroviral treatment as prevention: impact of the 'test and treat' strategy on the tuberculosis epidemic.

Antiretroviral therapy (ART) has been remarkably effective in ameliorating Human Immunodeficiency Virus (HIV)-associated morbidity and mortality. The rapid decline in viral load during ART also presents an opportunity to develop a "treatment as prevention" strategy in order to reduce HIV transmission at a population level. Modelling exercises have demonstrated that for this strategy to be effective, early initiation of ART with high coverage of the HIV-infected population will be required. The HIV epidemic has fueled a resurgence of tuberculosis (TB) particularly in sub- Saharan Africa and widespread early initiation of ART could also impact this epidemic via several mechanisms. The proportion of patients with low CD4 cell counts who are at high risk of TB disease from progression of both latent and new TB infection would be greatly reduced. Entry into a life-long ART program provides an ongoing opportunity for intensified TB case finding among the HIV-infected population. Regular screening for HIV infection also presents an opportunity for intensified TB case finding in the general population. The combined effect of reduced progression of infection to disease and intensified case finding could reduce the overall prevalence of infectious TB, thereby further decreasing TB transmission. In addition, decreasing prevalence of HIV infection would reduce the TB-susceptible pool within the population. The 'test and treat' strategy therefore has potential to reduce the TB risk at both an individual and a population level. In this paper we explore the expected "TB dividend" of wider access to ART and also explore the potential of the "test and treat" strategy to impact on TB transmission, particularly in the heavily burdened setting of sub- Saharan Africa

Detection of lipoarabinomannan (LAM) in urine is indicative of disseminated TB with renal involvement in patients living with HIV and advanced immunodeficiency: evidence and implications.

TB is the leading cause of HIV/AIDS-related deaths globally. New diagnostic tools are urgently needed to avert deaths from undiagnosed HIV-associated TB. Although simple assays that detect lipoarabinomannan (LAM) in urine have been commercially available for years, their specific role and utility were initially misunderstood, such that they have been slower to emerge from the diagnostics pipeline than otherwise might have been expected. In this article, we review and explain how urine-LAM assays should be understood as diagnostics for disseminated TB in HIV-positive patients with advanced immunodeficiency, in whom haematogenous TB dissemination to the kidneys serves as the primary mechanism by which LAM enters the urine. These insights are critical for the appropriate design of studies to evaluate these assays and to understand how they might be most usefully implemented. This understanding also supports the 2015 WHO recommendations on the restricted use of these assays in sick HIV-positive patients with advanced immunodeficiency

Prevalence of HIV-associated ophthalmic disease among patients enrolling for antiretroviral treatment in India: a cross-sectional study.

BACKGROUND: The ocular manifestations of HIV may lead to visual impairment or blindness. In India, patients typically initiate antiretroviral treatment (ART) with low CD4 cell counts when the risk of ocular complications may be high. The objective of this study was to determine the prevalence and types of HIV-associated ocular conditions in patients referred for ART in India. METHODS: This cross-sectional study was undertaken at a large public sector ART centre in Mumbai, India. Data collection including a standardised symptom screen, and an ophthalmic examination were performed on all consecutive patients satisfying the criteria for enrollment into the ART clinic irrespective of the presence or absence of ophthalmic/visual symptoms. RESULTS: Enrolled patients (n = 149) had a median CD4 cell count of 180 cell/microL (inter-quartile range [IQR], 106-253 cells/microL). The prevalence of HIV-associated ocular disease was 17.5% (95% CI, 11.2-23.6%) in all participants and 23.8% (95% CI: 14.5-33.1) in those with CD4 cell counts <200 cells/microL (n = 84). Only 7.7% of patients with HIV-associated ocular disease reported any eye symptoms in the standardised symptom screen. Objective visual impairment was detected in 20% of those with HIV-associated ocular disease compared to 6% in those without ocular manifestations (p = 0.02). Vitreoretinal disease was the most common manifestation, of which cytomegalovirus retinitis (CMVR) was the most frequent retinal infection (overall prevalence 8.7%, 95% CI: 4.1-13.3%). In a multivariable analysis, HIV-associated ocular disease was independently associated with a CD4 count <100 cells/microL (odds ratio [OR], 6.3, 95% CI: 1.5-25.9) and WHO clinical stages 3 and 4 (OR 9.4, 95% CI: 2.4-37.2). However, symptoms were not independently predictive of ocular disease. Sensitivity of ocular symptom screening was 7.7%, with a positive predictive value of 18% in this population. CONCLUSION: Over a fifth of unselected patients who are eligible for ART in this setting have HIV-related ocular disease of which CMVR is the most common form. Such patients may be at risk of developing ocular immune reconstitution phenomena during ART. Screening for ocular symptoms is not a reliable method to identify those with ocular morbidity and this highlights the need for routine ophthalmic screening prior to commencement of ART

Tuberculosis transmission to young children in a South African community: modeling household and community infection risks.

BACKGROUND: Tuberculosis transmission is determined by contact between infectious and susceptible individuals. A recent study reported a 4% annual risk of child tuberculosis infection in a southern African township. A model was used to explore the interactions between prevalence of adult tuberculosis infection, adult-to-child contacts, and household ventilation, which could result in such a high annual risk of tuberculosis infection. METHODS: Number of residents per household and tuberculosis incidence were derived from a household census and community tuberculosis registers. Using the Wells-Riley equation and probability analyses of contact between infectious adults with tuberculosis and preschool children, we estimated the annual risk of tuberculosis infection within and outside of the home. RESULTS: There was a mean of 2.2 adults per child-containing household with a 1.35% annual adult smear-positive tuberculosis notification rate. The maximal household annual risk of tuberculosis infection was 3%, which was primarily determined by the number of resident adults. Transmission risk outside the home increased with increasing number of households visited. Transmission probabilities were sensitive to exposure time, ventilation, and period of adult infectivity. The benefits of increased ventilation were greatest when the period of infectivity was reduced. Similar reductions in household transmission could be achieved by increasing ventilation from 2 to 6 air changes/hour or by separating child and adult sleeping areas. CONCLUSIONS: The annual risk of tuberculosis infection of preschool children predominantly results from infectious residents in the home. However, even with limited social interactions, a substantial proportion of transmissions may occur from nonresident adults. The benefits of increased ventilation are maximized when the period of infectivity is reduced by prompt treatment of source cases

Human cystic echinococcosis: evaluation of post-treatment serologic follow-up by IgG subclass antibody detection.

Assessment of post-treatment disease activity among patients with cystic echinococcosis (CE) is insensitive using detection of CE-specific total IgG antibody. This study investigated whether serum concentrations of CE-specific IgG subclasses 1-4 correlate better with disease activity than total IgG. We studied a cohort of patients (n = 28) with symptomatic CE treated with anthelminthic drugs and surgery and who were followed up clinically and radiologically for a mean of 5.6 years (range = 3-12 years). Serial archived sera collected during follow-up were retrospectively analyzed by enzyme-linked immunosorbent assays using crude horse hydatid cyst fluid as antigen. Changes in concentrations of antibodies were correlated with clinical and radiologic outcome. At diagnosis, concentrations of CE-specific total IgG, IgG1, and IgG2 antibodies were significantly elevated in a greater proportion of patients compared with IgG3 and IgG4 antibodies. During post-treatment follow up, the IgG2 antibody response provided the best correlate of disease activity