Additional file 1: of Latent class analysis to evaluate performance of point-of-care CCA for low-intensity Schistosoma mansoni infections in Burundi

Table S1. Bayesian Deviance Information Criterion (DIC) from models with different covariances fitted. Table S2. Summary statistics by school and prevalence estimates for each separate test by school. Table S3. Comparison of CCA results in Burundi and Leiden. Table S4. Test result combinations overall and by school, when CCA trace was considered negative and positive. Table S5. Estimate and 95% BCIs of difference between same estimates from trace negative and trace positive models presented in Table 4. Table S6. Output from LCA when specificity of CAA fixed to 100%. Table S7. Estimate and 95% BCIs of difference between same estimates from different models. Table S8 Estimated test and infection prevalence when specificity of CAA fixed to 100%. Fig. S1. Sensitivity of models to prior assumptions. Code S1. Code for running the LCA in R2OpenBugs (DOCX 845 kb

Effects of schistosomiasis on susceptibility to HIV-1 infection and HIV-1 viral load at HIV-1 seroconversion: A nested case-control study

<div><p>Background</p><p>Schistosomiasis affects 218 million people worldwide, with most infections in Africa. Prevalence studies suggest that people with chronic schistosomiasis may have higher risk of HIV-1 acquisition and impaired ability to control HIV-1 replication once infected. We hypothesized that: (1) pre-existing schistosome infection may increase the odds of HIV-1 acquisition and that the effects may differ between men and women, and (2) individuals with active schistosome infection at the time of HIV-1 acquisition may have impaired immune control of HIV-1, resulting in higher HIV-1 viral loads at HIV-1 seroconversion.</p><p>Methodology/Principal findings</p><p>We conducted a nested case-control study within a large population-based survey of HIV-1 transmission in Tanzania. A population of adults from seven villages was tested for HIV in 2007, 2010, and 2013 and dried blood spots were archived for future studies with participants’ consent. Approximately 40% of this population has <i>Schistosoma mansoni</i> infection, and 2% has <i>S</i>. <i>haematobium</i>. We tested for schistosome antigens in the pre- and post-HIV-1-seroconversion blood spots of people who acquired HIV-1. We also tested blood spots of matched controls who did not acquire HIV-1 and calculated the odds that a person with schistosomiasis would become HIV-1-infected compared to these matched controls. Analysis was stratified by gender. We compared 73 HIV-1 seroconverters with 265 controls. Women with schistosome infections had a higher odds of HIV-1 acquisition than those without (adjusted OR = 2.8 [1.2–6.6], p = 0.019). Schistosome-infected men did not have an increased odds of HIV-1 acquisition (adjusted OR = 0.7 [0.3–1.8], p = 0.42). We additionally compared HIV-1 RNA levels in the post-seroconversion blood spots in HIV-1 seroconverters with schistosomiasis versus those without who became HIV-infected in 2010, before antiretroviral therapy was widely available in the region. The median whole blood HIV-1 RNA level in the 15 HIV-1 seroconverters with schistosome infection was significantly higher than in the 22 without schistosomiasis: 4.4 [3.9–4.6] log₁₀ copies/mL versus 3.7 [3.2–4.3], p = 0.017.</p><p>Conclusions/Significance</p><p>We confirm, in an area with endemic <i>S</i>. <i>mansoni</i>, that pre-existing schistosome infection increases odds of HIV-1 acquisition in women and raises HIV-1 viral load at the time of HIV-1 seroconversion. This is the first study to demonstrate the effect of schistosome infection on HIV-1 susceptibility and viral control, and to differentiate effects by gender. Validation studies will be needed at additional sites.</p></div

Median log₁₀ whole blood HIV-1 RNA levels in recent HIV-1 seroconverters with and without schistosome infection.

<p>Summary plot depicting median and interquartile range of log₁₀ of whole blood HIV-1 RNA level in copies/mL as quantitated from dried blood spots in recent HIV-1 seroconverters with or without schistosome infection. The median viral load was 4.4 [3.9–4.6] HIV-1 RNA log copies/mL in those with schistosome infection versus 3.7 [3.2–4.3] among those without (p = 0.017 by Wilcoxon rank-sum test).</p

Prevalence of schistosome infection among HIV-1 seroconverters and matched controls, stratified by gender.

<p>In women, 44% of HIV-1 seroconverters had schistosome infection, compared to 30% of controls (p = 0.019). In men, 29% of HIV-1 seroconverters had schistosome infection, compared to 38% of controls (p = 0.42). These differences were not detectable when cases and controls were analyzed without stratification by gender.</p

Demographic and behavioral characteristics of HIV-1-infected cases and HIV-uninfected controls, by gender.

<p>Demographic and behavioral characteristics of HIV-1-infected cases and HIV-uninfected controls, by gender.</p