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38 - Poliomyelitis
- from Section 6 - Viral Infections
- Edited by David Mabey, London School of Hygiene and Tropical Medicine, Geoffrey Gill, University of Liverpool, Eldryd Parry, Martin W. Weber, Christopher J. M. Whitty, London School of Hygiene and Tropical Medicine
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- Book:
- Principles of Medicine in Africa
- Published online:
- 05 March 2013
- Print publication:
- 02 January 2013, pp 389-394
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Summary
The problem in Africa
Before the development of effective vaccines, poliomyelitis was a leading cause of permanent disability (Sabin, 1949). The World Health Organization has estimated that, in the absence of routine immunization against the disease, and the ongoing global effort to eradicate the causative viruses, at least 600 000 children would be permanently paralyzed by poliomyelitis each year (Sutter et al., 2008). Unfortunately, well into the twentieth century, it was often erroneously suggested that polio was not a serious public health problem in tropical, developing countries, including those in Africa, as it was postulated that early exposure of infants to the virus occurred when maternal antibodies levels were still high, thereby protecting them from paralytic disease.
However, since the 1970s, ‘lameness surveys’ in African countries clearly showed that post-polio paralysis occurred at the same rate as in Europe and America in the pre-vaccine era (Nicholas et al., 1977; Mabey, 1981) (Fig. 38.1). Overall, five to ten cases of lameness were reported per 1000 children. Consequently, the oral poliovirus vaccine (OPV) was eventually included in the basic course of vaccines recommended by the Expanded Programme on Immunization (EPI) in 1974. From the mid 1970s to 1990, the intensification of national EPI programmes improved OPV coverage and polio control throughout Africa and the rest of the world. These achievements were not uniform, though, such that by the late 1980s the majority of countries with <50 per cent coverage were in Africa, as well as a disproportionate share of the world's polio burden.
The science of EChO
- Giovanna Tinetti, James Y-K. Cho, Caitlin A. Griffith, Olivier Grasset, Lee Grenfell, Tristan Guillot, Tommi T. Koskinen, Julianne I. Moses, David Pinfield, Jonathan Tennyson, Marcell Tessenyi, Robin Wordsworth, Alan Aylward, Roy van Boekel, Angioletta Coradini, Therese Encrenaz, Ignas Snellen, Maria R. Zapatero-Osorio, Jeroen Bouwman, Vincent Coudé du Foresto, Mercedes Lopez-Morales, Ingo Mueller-Wodarg, Enric Pallé, Franck Selsis, Alessandro Sozzetti, Jean-Philippe Beaulieu, Thomas Henning, Michael Meyer, Giuseppina Micela, Ignasi Ribas, Daphne Stam, Mark Swain, Oliver Krause, Marc Ollivier, Emanuele Pace, Bruce Swinyard, Peter A.R. Ade, Nick Achilleos, Alberto Adriani, Craig B. Agnor, Cristina Afonso, Carlos Allende Prieto, Gaspar Bakos, Robert J. Barber, Michael Barlow, Peter Bernath, Bruno Bézard, Pascal Bordé, Linda R. Brown, Arnaud Cassan, Céline Cavarroc, Angela Ciaravella, Charles Cockell, Athéna Coustenis, Camilla Danielski, Leen Decin, Remco De Kok, Olivier Demangeon, Pieter Deroo, Peter Doel, Pierre Drossart, Leigh N. Fletcher, Matteo Focardi, Francois Forget, Steve Fossey, Pascal Fouqué, James Frith, Marina Galand, Patrick Gaulme, Jonay I. González Hernández, Davide Grassi, Matt J. Griffin, Ulrich Grözinger, Manuel Guedel, Pactrick Guio, Olivier Hainaut, Robert Hargreaves, Peter H. Hauschildt, Kevin Heng, David Heyrovsky, Ricardo Hueso, Pat Irwin, Lisa Kaltenegger, Patrick Kervella, David Kipping, Geza Kovacs, Antonino La Barbera, Helmut Lammer, Emmanuel Lellouch, Giuseppe Leto, Mercedes Lopez Morales, Miguel A. Lopez Valverde, Manuel Lopez-Puertas, Christophe Lovi, Antonio Maggio, Jean-Pierre Maillard, Jesus Maldonado Prado, Jean-Baptiste Marquette, Francisco J. Martin-Torres, Pierre Maxted, Steve Miller, Sergio Molinari, David Montes, Amaya Moro-Martin, Olivier Mousis, Napoléon Nguyen Tuong, Richard Nelson, Glenn S. Orton, Eric Pantin, Enzo Pascale, Stefano Pezzuto, Ennio Poretti, Raman Prinja, Loredana Prisinzano, Jean-Michel Réess, Ansgar Reiners, Benjamin Samuel, Jorge Sanz Forcada, Dimitar Sasselov, Giorgio Savini, Bruno Sicardy, Alan Smith, Lars Stixrude, Giovanni Strazzulla, Gautam Vasisht, Sandrine Vinatier, Serena Viti, Ingo Waldmann, Glenn J. White, Thomas Widemann, Roger Yelle, Yuk Yung, Sergey Yurchenko
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- Journal:
- Proceedings of the International Astronomical Union / Volume 6 / Issue S276 / October 2010
- Published online by Cambridge University Press:
- 10 November 2011, pp. 359-370
- Print publication:
- October 2010
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The science of extra-solar planets is one of the most rapidly changing areas of astrophysics and since 1995 the number of planets known has increased by almost two orders of magnitude. A combination of ground-based surveys and dedicated space missions has resulted in 560-plus planets being detected, and over 1200 that await confirmation. NASA's Kepler mission has opened up the possibility of discovering Earth-like planets in the habitable zone around some of the 100,000 stars it is surveying during its 3 to 4-year lifetime. The new ESA's Gaia mission is expected to discover thousands of new planets around stars within 200 parsecs of the Sun. The key challenge now is moving on from discovery, important though that remains, to characterisation: what are these planets actually like, and why are they as they are?
In the past ten years, we have learned how to obtain the first spectra of exoplanets using transit transmission and emission spectroscopy. With the high stability of Spitzer, Hubble, and large ground-based telescopes the spectra of bright close-in massive planets can be obtained and species like water vapour, methane, carbon monoxide and dioxide have been detected. With transit science came the first tangible remote sensing of these planetary bodies and so one can start to extrapolate from what has been learnt from Solar System probes to what one might plan to learn about their faraway siblings. As we learn more about the atmospheres, surfaces and near-surfaces of these remote bodies, we will begin to build up a clearer picture of their construction, history and suitability for life.
The Exoplanet Characterisation Observatory, EChO, will be the first dedicated mission to investigate the physics and chemistry of Exoplanetary Atmospheres. By characterising spectroscopically more bodies in different environments we will take detailed planetology out of the Solar System and into the Galaxy as a whole.
EChO has now been selected by the European Space Agency to be assessed as one of four M3 mission candidates.
Synergies between livestock production and hydrological function in Arenal, Costa Rica
- Bruce Aylward, Jaime Echeverría
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- Journal:
- Environment and Development Economics / Volume 6 / Issue 3 / July 2001
- Published online by Cambridge University Press:
- 25 June 2001, pp. 359-381
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Conventional wisdom amongst environmentalists holds that the cutting of tropical forest for livestock production is not only bad business but also bad for the environment. In particular, it is thought that conversion to pasture leads to a rise in the sedimentation of waterways and reservoirs, an increase in flooding and loss of dry season water supply. Using the case of the Rio Chiquito watershed (which drains into Lake Arenal, Costa Rica), the paper questions this conventional wisdom. The paper demonstrates that both livestock production and the associated downstream hydrological impacts represent important values to the local economy; values that significantly outweigh expected returns from options for reforestation or forest regeneration. Given that non-hydrological externalities associated with livestock production are expected to be of minimal importance in the watershed, there is little reason – as is often proposed – to foster large-scale reforestation of the watershed or to purchase land for protection. Instead efforts should focus on how to maximize the complementary returns from livestock and the support to hydroelectric power provided by water production.
5 - The role of plant screening and plant supply in biodiversity conservation, drug development and health care
- Edited by Timothy Swanson, University of Cambridge
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- Book:
- Intellectual Property Rights and Biodiversity Conservation
- Published online:
- 21 January 2010
- Print publication:
- 26 October 1995, pp 93-126
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Summary
Introduction
The medicinal value of plants is often touted as a rationale for preserving biodiversity. One way in which plants contribute to the health of people and their domesticated animals is through the use of plants in the development of new pharmaceutical products. This chapter examines the contribution that plants, particularly those found in the tropics, can make to the drug development process through their use in plant screening programs.
In the first half of the chapter, the connection between health care, drug development and plants is explored. It is argued that comparison of alternative modes of providing health care on the basis of their respective cost-effectiveness should, and probably will be, the standard applied to health care expenditures. The use of cost-effectiveness measures makes explicit the trade-offs made in choosing between different modes of health care provision.
In examining the connections between plants and drug development, the existence of trade-offs points to the need to assess potential substitutes or competing modes of health care provision. Arguments about the relative merits of drug development by ‘rational’ design or by ‘trial and error’ screening and of screening based on ethnobotanical information or the random selection of plants are evaluated in this context.