Compound A3 was identified in a high-throughput screen for inhibitors of influenza virus replication. It displays broad-spectrum antiviral activity, and at noncytotoxic concentrations it is shown to inhibit the replication of negative-sense RNA viruses (influenza viruses A and B, Newcastle disease virus, and vesicular stomatitis virus), positive-sense RNA viruses (Sindbis virus, hepatitis C virus, West Nile virus, and dengue virus), DNA viruses (vaccinia virus and human adenovirus), and retroviruses (HIV). In contrast to mammalian cells, inhibition of viral replication by A3 is absent in chicken cells, which suggests species-specific activity of A3. Correspondingly, the antiviral activity of A3 can be linked to a cellular protein, dihydroorotate dehydrogenase (DHODH), which is an enzyme in the de novo pyrimidine biosynthesis pathway. Viral replication of both RNA and DNA viruses can be restored in the presence of excess uracil, which promotes pyrimidine salvage, or excess orotic acid, which is the product of DHODH in the de novo pyrimidine biosynthesis pathway. Based on these findings, it is proposed that A3 acts by depleting pyrimidine pools, which are crucial for efficient virus replication.

Throughout all stages of programmes for the prevention of mother-to-child-transmission of HIV (PMTCT), high dropout rates are common. Increased male involvement and couples' joint HIV counselling/testing during antenatal care (ANC) seem crucial for improving PMTCT outcomes. Our study assessed male attitudes regarding partner involvement into ANC/PMTCT services in Mbeya Region, Tanzania, conducting 124 individual interviews and six focus group discussions. Almost all respondents generally supported PMTCT interventions. Mentioned barriers to ANC/PMTCT attendance included lacking information/knowledge, no time, neglected importance, the services representing a female responsibility, or fear of HIV-test results. Only few perceived couple HIV counselling/testing as disadvantageous. Among fathers who had refused previous ANC/PMTCT attendance, most had done so even though they were not perceiving a disadvantage about couple counselling/testing. The contradiction between men's beneficial attitudes towards their involvement and low participation rates suggests that external barriers play a large role in this decision-making process and that partner's needs should be more specifically addressed in ANC/PMTCT services.

BackgroundSince 2008, Tanzanian guidelines for prevention of mother-to-child-transmission of HIV (PMTCT) recommend combination regimen for mother and infant starting in gestational week 28. Combination prophylaxis is assumed to be more effective and less prone to resistance formation compared to single-drug interventions, but the required continuous collection and intake of drugs might pose a challenge on adherence especially in peripheral resource-limited settings. This study aimed at analyzing adherence to combination prophylaxis under field conditions in a rural health facility in Kyela, Tanzania.Methods and FindingsA cohort of 122 pregnant women willing to start combination prophylaxis in Kyela District Hospital was enrolled in an observational study. Risk factors for decline of prophylaxis were determined, and adherence levels before, during and after delivery were calculated. In multivariate analysis, identified risk factors for declining pre-delivery prophylaxis included maternal age below 24 years, no income-generating activity, and enrolment before 24.5 gestational weeks, with odds ratios of 5.8 (P = 0.002), 4.4 (P = 0.015) and 7.8 (P = 0.001), respectively. Women who stated to have disclosed their HIV status were significantly more adherent in the pre-delivery period than women who did not (P = 0.004). In the intra- and postpartum period, rather low drug adherence rates during hospitalization indicated unsatisfactory staff performance. Only ten mother-child pairs were at least 80% adherent during all intervention phases; one single mother-child pair met a 95% adherence threshold.ConclusionsAchieving adherence to combination prophylaxis has shown to be challenging in this rural study setting. Our findings underline the need for additional supervision for PMTCT staff as well as for clients, especially by encouraging them to seek social support through status disclosure. Prophylaxis uptake might be improved by preponing drug intake to an earlier gestational age. Limited structural conditions of a healthcare setting should be taken into serious account when implementing PMTCT combination prophylaxis.

Summaryobjectives: To evaluate risk factors for treatment denial and loss to follow-up in an antiretroviral treatment (ART) cohort in a rural African setting in western Kenya.method: Sociodemographic and clinical data of patients enrolled in an ART cohort were collected within 18 months of an observational longitudinal study and analysed by logistic and Cox regression models.results: Of 159 patients with treatment indication 35 (22%) never started ART. Pregnancy [adjusted odds ratio (AOR) 3.60, 95% confidence interval (CI) 1.10-11.8; P ¼ 0.035] and lower level of education (AOR 3.80, 95% CI 1.14-12.7; P ¼ 0.03) were independently associated with treatment denial. The incidence of total loss of patients under therapy was 43.2 per 100 person years (pys) (mortality rate 19.2 per 100 pys plus drop out rate 24 per 100 pys). Older age [adjusted hazard ratio (AHR) 1.06, 95% CI 1.01-1.12; P ¼ 0.04], AIDS before starting treatment (AHR 5.83, 95% CI 1.15-29.5; P ¼ 0.03) and incomplete adherence to treatment (AHR 1.05, 95% CI 1.03-1.07; P < 0.001) were independent risk factors for death. Incomplete adherence also independently predicted drop out because of other reasons (AHR 1.06, 95% CI 1.04-1.09; P < 0.001).conclusion: Pregnancy and lower level of education, higher age, advanced AIDS stage and impaired compliance to ART were identified as risk factors for treatment denial and death, respectively. Adequate counselling strategies for patients with these characteristics could help to improve adherence and outcome of treatment programmes in resource-limited settings.keywords antiretroviral treatment, adherence, loss to follow-up, treatment denial, resource-limited setting

Multiple APOBEC3 proteins are expressed in HIV-1 target cells, but their individual contributions to viral suppression when expressed at endogenous levels remain largely unknown. We used an HIV NL4-3 mutant that selectively counteracts APOBEC3G (A3G) but not APOBEC3F (A3F) to dissect the relative contribution of A3F to the inhibition of HIV-1 replication in primary human lymphocytes (peripheral blood mononuclear cells [PBMCs]). This HIV Vif mutant replicated similarly to wild-type virus in PBMCs, suggesting that the effect of A3F on HIV restriction in these cells is limited. The different A3F variants found in PMBC donors displayed either comparable activity or less activity than wild-type A3F. Lastly, the endogenous A3F mRNA and protein expression levels in PBMCs were considerably lower than those of A3G. Our results suggest that A3F neutralization is dispensable for HIV-1 replication in primary human T-lymphocytes.