Attempts to find a cure for HIV infection are hindered by the presence of viral reservoirs that resist highly active antiretroviral therapy. To identify the properties of these reservoirs, four SIV239-infected Rhesus macaques were treated with combined antiretroviral therapy (cART) for 1 year. While plasma viral RNA (vRNA) was effectively suppressed, a systemic analysis revealed that vRNA was distributed in the following order: lymphatic tissues>lungs and intestine>other tissues. Histochemistry yielded no cells with viral signals. To increase the chance of detection, two additional SIV-infected animals were treated and analyzed on Day 10 after the cessation of cART. These animals exhibited similar vRNA distribution patterns to the former animals, and immunohistochemistry revealed Nef-positive T lymphocytes predominantly in the follicles of mesenteric lymph nodes (MLNs). These data suggest that lymphatic tissues, including MLNs, contain major cellular reservoirs that cause rebound of plasma viremia upon cessation of therapy.

Dengue virus (DENV) infectious disease is a major public health problem worldwide; however, licensed vaccines or specific antiviral drugs against this infection are not available. To identify novel anti-DENV compounds, we screened 1280 pharmacologically active compounds using focus reduction assay. Bromocriptine (BRC) was found to have potent anti-DENV activity and low cytotoxicity (half maximal effective concentration [EC50], 0.8-1.6 μM; and half maximal cytotoxicity concentration [CC50], 53.6 μM). Time-of-drug-addition and time-of-drug-elimination assays suggested that BRC inhibits translation and/or replication steps in the DENV life cycle. A subgenomic replicon system was used to verify that BRC restricts RNA replication step. Furthermore, a single amino acid substitution (N374H) was detected in the NS3 protein that conferred resistance to BRC. In summary, BRC was found to be a novel DENV inhibitor and a potential candidate for the treatment of DENV infectious disease.

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Hypochlorous acid (HOCl) solutions were evaluated for their virucidal ability against a low pathogenic avian influenza virus (AIV), H7N1. HOCl solutions containing 50, 100 and 200 ppm chlorine (pH 6) or their sprayed solutions (harvested in dishes placed at 1 or 30 cm distance between the spray nozzle and dish) were mixed with the virus with or without organic materials (5% fetal bovine serum: FBS). Under plain diluent conditions (without FBS), harvested solutions of HOCl after spraying could decrease the AIV titer by more than 1,000 times, to an undetectable level (< 2.5 log10TCID50/ml) within 5 sec, with the exception of the 50 ppm solution harvested after spraying at the distance of 30 cm. Under the dirty conditions (in the presence of 5% FBS), they lost their virucidal activity. When HOCl solutions were sprayed directly on the virus on rayon sheets for 10 sec, the solutions of 100 and 200 ppm could inactivate AIV immediately after spraying, while 50 ppm solution required at least 3 min of contact time. In the indirect spray form, after 10 sec of spraying, the lids of the dishes were opened to expose the virus on rayon sheets to HOCl. In this form, the 200 ppm solution inactivated AIV within 10 min of contact, while 50 and 100 ppm could not inactivate it. These data suggest that HOCl can be used in spray form to inactivate AIV at the farm level.

The efficacy and stability of scallop shell powder (SSP) were investigated, in terms of its capacity to inactivate avian influenza virus (AIV), and compared with slaked lime (SL). An environmental simulation was conducted by emulating sunlight and wet-dry conditions. The powders were collected at consecutive 2-week intervals under sunlight and upon every resuspension. These materials were tested by mixing them with AIV and incubating the mixture for 3 min or 20 h, followed by AIV titration. At the same time, a pH buffering test was conducted by neutralization with Tris-HCl. The results revealed that SSP and SL have high alkalinity and excellent ability to inactivate AIV. In a simulated harsh environment, SSP and SL retained a satisfactory ability to inactivate AIV within 20 h throughout the experimental procedure. However, SSP was able to inactivate AIV during a short contact period (3 min), even under harsh conditions, and it was more resistant than SL to neutralization.