Influenza Viruses

Davenport, Fred M.

doi:10.1007/978-1-4613-3237-4_14

Cited by 7 publications

(3 citation statements)

References 65 publications

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“…ent form and an ageindependent form, is suggested by the pattern of correlations. It is possible that the age-independent deaths re resent the influpandemic, which resulted in a high death rate at all ages compared with more t pica1 1919, which tend to affect the young and old differentia11 (Davenport, 1976). Another hypothetical but more general explanation for the high negative correlations between the immature and residual components of all the infectious diseases concerns epidemic vs. endemic diseases.…”

Section: Discussionmentioning

confidence: 92%

Causes of death and the components of mortality: Testing the biological interpretations of a competing hazards model

Gage

1991

American J Hum Biol

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Biological interpretations of a competing hazards model intended to express the age pattern of mortality throughout the life span are evaluated using cause of death data. The model examined is the Siler model, which consists of three competing hazards, immature, residual, and senescent. The data employed are the worldwide sample of life tables and decremented life tables, that is, life tables with a cause of death eliminated, assembled by Preston et al. (Causes of Death Life Tables for National Populations. New York: Seminar Press, 1972). The results indicate that causes of death are accounted for by the model in a manner consistent with the biological interpretations of the hazard functions. For example, the cardiovascular diseases, neoplasms, and other degenerative diseases are accounted for by the senescent component of morality. This is a valuable characteristic of the model that may prove useful for assessing errors in cause of death data and identifying variation in the impact of a cause of death on the age patterns of mortality. For example, only 30% of deaths classified as due to other and unknown causes are attributed by the model to the senescent component of mortality and are consequently likely to be due to degenerative diseases. This finding contradicts the conventional assumption that the majority of other and unknown causes of death are due to the degenerative diseases. Additional results show that certain causes of death, such as influenza, pneumonia, and bronchitis, can occur in different components of mortality, suggesting that some categories of death may express several different etiologies. Partial correlation analysis indicates that much of this variation in etiology occurs among (and not within) populations. It is concluded that the Siler model is a useful framework for studying historical and/or crossnational trends in mortality.A number of models have been proposed that account for changes in age-specific mortality rates over the entire human life s an.ards functions (Theile, 1871;Siler, 1979; Heligman and Pollard, 1980;Mode and Busby, 1982;Mode and Jacobson, 1984) and the relational methods (Brass, 1981;Ewbank et al., 1983). The hazard models are nonlinear mathematical functions intended to represent the age related changes in the risk of dying, also known as the hazard function, the instantaneous death rate, or the force of mortality. The relational methods, on the other hand, obtain the basic shape of the human mortality curve from a standard tabular life table and then use linear re ession to fit the logit transform of the stan f-ard survivorship curve to the logit These models are often divided into the R aztransform of the observed survivorship curve. Both classes of models are useful for graduatin the a e-s ecific mortality rates of a life ta % le an C i W or or summarizing a life table by a smaller number of parameters.One advanta e of the relational models is that they ten % to contain fewer parameters than the hazard models and are consequently easier to fit to data. Th...

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Section: Discussionmentioning

confidence: 92%

Causes of death and the components of mortality: Testing the biological interpretations of a competing hazards model

Gage

1991

American J Hum Biol

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“…The values in the tables clearly illustrate that influenza virus will be distinctly inactivated in different cities and at different times of the year. For example, at winter solstice (December, in the northern hemisphere), just after the beginning of the usual flu season (which peaks in January [26]) influenza virus exposed to full sunlight will be reduced by at least 99% (2 log 10 ) during a single day in Mexico City and other cities between the Tropics of Cancer and Capricorn, and by at least 90% (1 log 10 ) in Miami and Houston in the U.S. and Cairo, Egypt and Shanghai, China in the lower latitudes of the temperate zone, but will remain largely unaffected by the sun in Boston or Seattle in the U.S. or any of the European cities. Of course, the same trend applies to the Southern Hemisphere where winter begins in June.…”

Section: Resultsmentioning

confidence: 99%

Inactivation of Influenza Virus by Solar Radiation

Sagripanti

Lytle

2007

Photochem & Photobiology

122

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Influenza virus is readily transmitted by aerosols and its inactivation in the environment could play a role in limiting the spread of influenza epidemics. Ultraviolet radiation in sunlight is the primary virucidal agent in the environment but the time that influenza virus remains infectious outside its infected host remains to be established. In this study, we calculated the expected inactivation of influenza A virus by solar ultraviolet radiation in several cities of the world during different times of the year. The inactivation rates reported here indicate that influenza A virions should remain infectious after release from the host for several days during the winter "flu season" in many temperate-zone cities, with continued risk for reaerosolization and human infection. The correlation between low and high solar virucidal radiation and high and low disease prevalence, respectively, suggest that inactivation of viruses in the environment by solar UV radiation plays a role in the seasonal occurrence of influenza pandemics.

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“…The 1957 experience emphasised that the dominant antigen of an earlier strain may return to epidemic circulation when the population loses its immunity by aging, death and a growing replacement by susceptibles. 8,14,15 A compound vaccine could also provide conditioning to varied antigens early in life which could be boosted promptly by subsequent vaccination to estab-lish an enhanced broad resistance rather than acquiring it by repeated infections. Obviously, this approach requires a comprehensive immunologic effort and flexibility in formulation of vaccines, but present knowledge suggests it has a reasonable potential for addressing the great antigenic variability in influenza viruses.…”

Section: Historical Backgroundmentioning

confidence: 99%

The development of live attenuated cold-adapted influenza virus vaccine for humans

Maassab¹,

Bryant²

1999

Rev. Med. Virol.

143

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A procedure to attenuate live influenza virus of type A and type B was developed using adaptation of the virus to grow at 25 C (cold adaptation; ca). Through a series of stepwise passages, two stable mutants were obtained and designated as 'Master' strains, one for type A influenza virus (A/Ann Arbor/6/60-H2N2) and one for type B influenza virus (B/Ann Arbor/1/66). These mutants were used in genetic reassortment using either the classical method or more recently described reverse genetics to update the relevant surface antigens of the circulating strains of influenza virus. The derivation is based on the concept of 6/2 where 6 signifies the six internal genes of the master strain and 2 refers to the two genes coding for the two surface glycoproteins HA and NA of the circulating influenza virus. The advantages of this vaccine were demonstrated to be (1) proper level of attentuation, (2) non-transmissibility, (3) genetic stability, (4) presence of the ca and ts markers and (5) immunogenicity involving both local and the cell-mediated immune responses. The clinical trials in infants, children, adults and elderly have provided the necessary data for eventual licensing of this vaccine. The ease of administration (intranasal) safety and high efficacy make this vaccine suitable to prevent influenza virus infection in all age groups.

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Influenza Viruses

Cited by 7 publications

References 65 publications

Causes of death and the components of mortality: Testing the biological interpretations of a competing hazards model

Causes of death and the components of mortality: Testing the biological interpretations of a competing hazards model

Inactivation of Influenza Virus by Solar Radiation

The development of live attenuated cold-adapted influenza virus vaccine for humans

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