64 research outputs found

    From Emergence to Eradication: The Epidemiology of Poliomyelitis Deconstructed

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    Poliomyelitis has appeared in epidemic form, become endemic on a global scale, and been reduced to near-elimination, all within the span of documented medical history. Epidemics of the disease appeared in the late 19th century in many European countries and North America, following which polio became a global disease with annual epidemics. During the period of its epidemicity, 1900–1950, the age distribution of poliomyelitis cases increased gradually. Beginning in 1955, the creation of poliovirus vaccines led to a stepwise reduction in poliomyelitis, culminating in the unpredicted elimination of wild polioviruses in the United States by 1972. Global expansion of polio immunization resulted in a reduction of paralytic disease from an estimated annual prevaccine level of at least 600,000 cases to fewer than 1,000 cases in 2000. Indigenous wild type 2 poliovirus was eradicated in 1999, but unbroken localized circulation of poliovirus types 1 and 3 continues in 4 countries in Asia and Africa. Current challenges to the final eradication of paralytic poliomyelitis include the continued transmission of wild polioviruses in endemic reservoirs, reinfection of polio-free areas, outbreaks due to circulating vaccine-derived polioviruses, and persistent excretion of vaccine-derived poliovirus by a few vaccinees with B-cell immunodeficiencies. Beyond the current efforts to eradicate the last remaining wild polioviruses, global eradication efforts must safely navigate through an unprecedented series of endgame challenges to assure the permanent cessation of all human poliovirus infections

    Disruption of the IS6-AID Linker Affects Voltage-gated Calcium Channel Inactivation and Facilitation

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    Two processes dominate voltage-gated calcium channel (CaV) inactivation: voltage-dependent inactivation (VDI) and calcium-dependent inactivation (CDI). The CaVβ/CaVα1-I-II loop and Ca2+/calmodulin (CaM)/CaVα1–C-terminal tail complexes have been shown to modulate each, respectively. Nevertheless, how each complex couples to the pore and whether each affects inactivation independently have remained unresolved. Here, we demonstrate that the IS6–α-interaction domain (AID) linker provides a rigid connection between the pore and CaVβ/I-II loop complex by showing that IS6-AID linker polyglycine mutations accelerate CaV1.2 (L-type) and CaV2.1 (P/Q-type) VDI. Remarkably, mutations that either break the rigid IS6-AID linker connection or disrupt CaVβ/I-II association sharply decelerate CDI and reduce a second Ca2+/CaM/CaVα1–C-terminal–mediated process known as calcium-dependent facilitation. Collectively, the data strongly suggest that components traditionally associated solely with VDI, CaVβ and the IS6-AID linker, are essential for calcium-dependent modulation, and that both CaVβ-dependent and CaM-dependent components couple to the pore by a common mechanism requiring CaVβ and an intact IS6-AID linker

    Border Insecurity: Reading Transnational Environments in Jim Lynch’s Border Songs

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    This article applies an eco-critical approach to contemporary American fiction about the Canada-US border, examining Jim Lynch’s portrayal of the British Columbia-Washington borderlands in his 2009 novel Border Songs. It argues that studying transnational environmental actors in border texts—in this case, marijuana, human migrants, and migratory birds—helps illuminate the contingency of political boundaries, problems of scale, and discourses of risk and security in cross-border regions after 9/11. Further, it suggests that widening the analysis of trans-border activity to include environmental phenomena productively troubles concepts of nature and regional belonging in an era of climate change and economic globalization. Cet article propose une lecture écocritique de la fiction étatsunienne contemporaine portant sur la frontière entre le Canada et les États-Unis, en étudiant le portrait donné par Jim Lynch de la région frontalière entre la Colombie-Britannique et Washington dans son roman Border Songs, paru en 2009. L’article soutient que l’étude, dans les textes sur la frontière, des acteurs environnementaux transnationaux – dans ce cas-ci, la marijuana, les migrants humains et les oiseaux migratoires – jette un jour nouveau sur la contingence des limites territoriales politiques, des problèmes d’échelle et des discours sur le risque et la sécurité des régions transfrontalières après les évènements du 11 septembre 2001. Il suggère également qu’en élargissant l’analyse de l’activité transfrontalière pour y inclure les phénomènes environnementaux, on brouille de façon productive les concepts de nature et d’appartenance régionale d’une époque marquée par les changements climatiques et la mondialisation de l’économie

    A Live-Attenuated HSV-2 ICP0− Virus Elicits 10 to 100 Times Greater Protection against Genital Herpes than a Glycoprotein D Subunit Vaccine

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    Glycoprotein D (gD-2) is the entry receptor of herpes simplex virus 2 (HSV-2), and is the immunogen in the pharmaceutical industry's lead HSV-2 vaccine candidate. Efforts to prevent genital herpes using gD-2 subunit vaccines have been ongoing for 20 years at a cost in excess of $100 million. To date, gD-2 vaccines have yielded equivocal protection in clinical trials. Therefore, using a small animal model, we sought to determine if a live-attenuated HSV-2 ICP0− virus would elicit better protection against genital herpes than a gD-2 subunit vaccine. Mice immunized with gD-2 and a potent adjuvant (alum+monophosphoryl lipid A) produced high titers of gD-2 antibody. While gD-2-immunized mice possessed significant resistance to HSV-2, only 3 of 45 gD-2-immunized mice survived an overwhelming challenge of the vagina or eyes with wild-type HSV-2 (MS strain). In contrast, 114 of 115 mice immunized with a live HSV-2 ICP0− virus, 0ΔNLS, survived the same HSV-2 MS challenges. Likewise, 0ΔNLS-immunized mice shed an average 125-fold less HSV-2 MS challenge virus per vagina relative to gD-2-immunized mice. In vivo imaging demonstrated that a luciferase-expressing HSV-2 challenge virus failed to establish a detectable infection in 0ΔNLS-immunized mice, whereas the same virus readily infected naïve and gD-2-immunized mice. Collectively, these results suggest that a HSV-2 vaccine might be more likely to prevent genital herpes if it contained a live-attenuated HSV-2 virus rather than a single HSV-2 protein

    Attenuated influenza A vaccine (Alice) in an adult population: vaccine-related illness, serum and nasal antibody production, and intrafamily transmission

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    Ninety-five healthy adults, ages 18 to 56 years, received two intranasal doses, 2 weeks apart, of a live, attenuated, influenza type A (H3N2) vaccine (an inhibitor-resistant recombinant strain of A/England/42/72 named "Alice"). Ninety-two persons were given placebos similarly. Ninety-three percent of 68 subjects with initial serum hemagglutination-inhibition (HI) titers of greater than or equal to 1:40 to influenza A (H3N2) had a fourfold or greater antibody increase in postvaccination sera. Forty-four percent of 27 subjects with an initial HI titer of greater than or equal to 1:80 had similar increases. Overall, 77% of vaccinees had fourfold or greater antibody titer increases. Vaccinees had geometric mean serum HI titers (GMT) of 1:26, 1:123, and 1:166 at 0, 14, and 30 days, respectively. The GMTs for placebos were 1:21, 1:22, and 1:21. Thirty-five vaccinees were examined for both serum and nasal antibody; 89% had significant increases in one or both. Nasal antibody response was directly related to the level of initial serum HI titer in that 83% of 12 persons with prevaccination HI titers of 1:80 greater than or equal to 1:80 showed significant nasal antibody rises, whereas only 61% of the remaining 23 subjects with prevaccination HI titers of less than or equal to 1:40 did so. The number and severity of clinical signs and symptoms reported by vaccinees and placebos did not differ significantly. The greatest differences noted between groups were for nasal congestion on days 0 to 6 (8.3%) and rhinitis on days 14 to 20 (5.9%). Four vaccinees shed Alice after primary vaccination, but viral titers were low (10 to 100 tissue culture-infective doses/ml). One member in each of 15 cohabiting male-female couples received Alice while the other received a placebo; one of the placebo members had significant increases in serum and nasal antibody, indicating a possible transmission.</jats:p

    Failure of Naturally Acquired Rhinovirus Infections to Produce Temporal Immunity to Heterologous Serotypes

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    Nine naturally acquired rhinovirus infections in 31 asthmatic and nonasthmatic children were succeeded rapidly (2 to 26 days) by infections with heterologous rhinovirus.</jats:p
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