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Viral evolution is an important aspect of the epidemiology of viral diseases such as influenza (influenza virus), AIDS , and hepatitis (e.g. HCV). The rapidity of viral mutation also causes problems in the development of successful vaccines and antiviral drugs , as resistant mutations often appear within weeks or months after the beginning of a ...
New viruses and strains of viruses were discovered in every decade of the second half of the 20th century. These discoveries have continued in the 21st century as new viral diseases such as SARS [72] and nipah virus [73] have emerged. Despite scientists' achievements over the past one hundred years, viruses continue to pose new threats and ...
The passage of virus produces mutations within the viral genome, and hinders the virus's ability to infect nervous tissue. [6] Both vaccines have been used for decades to induce immunity to polio, and to stop the spread of the infection. However, OPV has several advantages; because the vaccine is introduced in the gastrointestinal tract, the ...
Antigenic drift is a kind of genetic variation in viruses, arising from the accumulation of mutations in the virus genes that code for virus-surface proteins that host antibodies recognize. This results in a new strain of virus particles that is not effectively inhibited by the antibodies that prevented infection by previous strains.
[1] [2] The suboptimal antibodies can result from natural infection or from vaccination. ADE may cause enhanced respiratory disease, but is not limited to respiratory disease. [3] It has been observed in HIV, RSV, and Dengue virus and is monitored for in vaccine development. [4]
The virulence of the virus may be changed, [5] or a virus could evolve to become adapted to a different host environment than that in which it is typically found. [5] Relatively few passages are necessary to produce a noticeable change in a virus; for instance, a virus can typically adapt to a new host within ten or so passages. [5]
A founder virus can introduce a different phenotype for the ensuing evolution. Evolution of viruses in nature and as disease agents can be viewed as succession of mutant spectrum alterations, subjected to expansions and reductions of population size in a continuous interplay of positive and negative selection and random drift.
Viral phylodynamics is the study of how epidemiological, immunological, and evolutionary processes act and potentially interact to shape viral phylogenies. [1] Since the term was coined in 2004, research on viral phylodynamics has focused on transmission dynamics in an effort to shed light on how these dynamics impact viral genetic variation.