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Walter R. Dowdle

Bio: Walter R. Dowdle is an academic researcher from World Health Organization. The author has contributed to research in topics: Poliomyelitis eradication & Disease Eradication. The author has an hindex of 7, co-authored 10 publications receiving 763 citations.

Papers
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Journal ArticleDOI
TL;DR: Conditions that lead to influenza pandemics are not fully understood and need to be understood in order to be able to protect against future outbreaks.
Abstract: Influenza pandemic risk assessment is an uncertain art. The theory that influenza A virus pandemics occur every 10 to 11 years and seroarcheologic evidence of virus recycling set the stage in early 1976 for risk assessment and risk management of the Fort Dix, New Jersey, swine influenza outbreak. Additional data and passage of time proved the theory untenable. Much has been learned about influenza A virus and its natural history since 1976, but the exact conditions that lead to the emergence of a pandemic strain are still unknown. Current avian influenza events parallel those of swine influenza in 1976 but on a larger and more complex scale. Pre- and postpandemic risk assessment and risk management are continuous but separate public health functions.

63 citations

BookDOI
16 Sep 2011
TL;DR: The most pertinent lessons were in assessing operational feasibility, sustaining and applying research, conducting effective advocacy at the subnational level, operating in insecure areas, and anticipating and addressing vulnerabilities in areas with especially weak health systems.
Abstract: Given the substantial infl uence that the Global Polio Eradication Initiative can be expected to have on future eradication initiatives, it seems increasingly important to identify and analyze lessons from each phase of this program. The protracted “tail” of the polio eradication initiative currently appears to be disproportionately infl uencing discussion of, and decisions on, future eradication efforts, particularly with respect to the potential merits of a future measles eradication effort. Consequently, for the purposes of this chapter the “late stages” of the polio initiative have been analyzed, with most attention to those geographical areas that have never interrupted wild poliovirus transmission and those which have been regularly reinfected. The major lessons that have been identifi ed might be applied earlier in future eradication initiatives, ultimately increasing the prospects for their launch, early scale-up, and successful conclusion. The most pertinent lessons identifi ed were in assessing operational feasibility, sustaining and applying research, conducting effective advocacy at the subnational level, operating in insecure areas, and anticipating and addressing vulnerabilities in areas with especially weak health systems.

49 citations

Journal ArticleDOI
30 Dec 2011-Vaccine
TL;DR: Global decisions on disease eradication should include careful consideration of opportunity costs and prioritization of limited global health resources, with the objective of providing the most appropriate, cost-beneficial, and equitable outcome of disease control.

47 citations

Journal ArticleDOI
TL;DR: Using their experiences from, and analysis of, global campaigns to eradicate smallpox, poliomyelitis, and measles, Myron Levine and colleagues derive lessons for malaria eradication.
Abstract: By examining the role research has played in eradication or regional elimination initiatives for three viral diseases—smallpox, poliomyelitis, and measles—we derive nine cross-cutting lessons applicable to malaria eradication. In these initiatives, some types of research commenced as the programs began and proceeded in parallel. Basic laboratory, clinical, and field research all contributed notably to progress made in the viral programs. For each program, vaccine was the lynchpin intervention, but as the programs progressed, research was required to improve vaccine formulations, delivery methods, and immunization schedules. Surveillance was fundamental to all three programs, whilst polio eradication also required improved diagnostic methods to identify asymptomatic infections. Molecular characterization of pathogen isolates strengthened surveillance and allowed insights into the geographic source of infections and their spread. Anthropologic, sociologic, and behavioural research were needed to address cultural and religious beliefs to expand community acceptance. The last phases of elimination and eradication became increasingly difficult, as a nil incidence was approached. Any eradication initiative for malaria must incorporate flexible research agendas that can adapt to changing epidemiologic contingencies and allow planning for posteradication scenarios.

29 citations


Cited by
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Journal ArticleDOI
TL;DR: The Malaria Eradication Research Agenda initiative and the set of articles published in this PLoS Medicine Supplement that distill the research questions key to malaria eradication are introduced.
Abstract: The interruption of malaria transmission worldwide is one of the greatest challenges for international health and development communities. The current expert view suggests that, by aggressively scaling up control with currently available tools and strategies, much greater gains could be achieved against malaria, including elimination from a number of countries and regions; however, even with maximal effort we will fall short of global eradication. The Malaria Eradication Research Agenda (malERA) complements the current research agenda—primarily directed towards reducing morbidity and mortality—with one that aims to identify key knowledge gaps and define the strategies and tools that will result in reducing the basic reproduction rate to less than 1, with the ultimate aim of eradication of the parasite from the human population. Sustained commitment from local communities, civil society, policy leaders, and the scientific community, together with a massive effort to build a strong base of researchers from the endemic areas will be critical factors in the success of this new agenda.

646 citations

Journal ArticleDOI
27 Jun 2008-Science
TL;DR: De novo large DNA molecules are synthesized using hundreds of over-or underrepresented synonymous codon pairs to encode the poliovirus capsid protein and polioviruses containing such amino acid–independent changes were attenuated in mice.
Abstract: As a result of the redundancy of the genetic code, adjacent pairs of amino acids can be encoded by as many as 36 different pairs of synonymous codons. A species-specific "codon pair bias" provides that some synonymous codon pairs are used more or less frequently than statistically predicted. We synthesized de novo large DNA molecules using hundreds of over-or underrepresented synonymous codon pairs to encode the poliovirus capsid protein. Underrepresented codon pairs caused decreased rates of protein translation, and polioviruses containing such amino acid-independent changes were attenuated in mice. Polioviruses thus customized were used to immunize mice and provided protective immunity after challenge. This "death by a thousand cuts" strategy could be generally applicable to attenuating many kinds of viruses.

618 citations

Journal ArticleDOI
03 Sep 2020-Cell
TL;DR: This work states that disease emergence reflects dynamic balances and imbalances, within complex globally-distributed ecosystems comprised of humans, animals, pathogens, and the environment, which is a necessary step in controlling future devastating disease emergences.

396 citations

Book
31 Aug 2009
TL;DR: The evolution and emergence of hantaviruses is more complex than previously anticipated, and may serve as a realistic model for other viral groups.
Abstract: Hantaviruses are a major class of zoonotic pathogens and cause a variety of severe diseases in humans. For most of the last 50 years rodents have been considered to be the primary hosts of hantaviruses, with hantavirus evolution thought to reflect a process of virus-rodent co-divergence over a time-scale of millions of years, with occasional spill-over into humans. However, recent discoveries have revealed that hantaviruses infect a more diverse range of mammalian hosts, particularly Chiroptera (bats) and Soricomorpha (moles and shrews), and that cross-species transmission at multiple scales has played an important role in hantavirus evolution. As a consequence, the evolution and emergence of hantaviruses is more complex than previously anticipated, and may serve as a realistic model for other viral groups.

345 citations

Journal ArticleDOI
TL;DR: 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.
Abstract: 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.

343 citations