Читать книгу Principles of Virology - Jane Flint, S. Jane Flint - Страница 21

 Viruses are obligate intracellular parasites and depend on their host cell for all aspects of their reproduction.

 The field of virology encompasses viral discovery; the study of virus structure and reproduction; and the importance of viruses in biology, ecology, and disease.

 This text focuses primarily on viruses that infect vertebrates, especially humans, but it is important to keep in mind that viruses infect all living things including insects, plants, and bacteria.

 Viruses are not solely pathogenic nuisances; they can be beneficial. Viruses contribute to ecological homeostasis, keep our immune responses activated and alert, and can be used as molecular flashlights to illuminate cellular processes.

 Viruses have been part of all of human history: they were present long before Homo sapiens evolved, and the majority of human infections were likely acquired from other animals (zoonoses).

 While Koch’s postulates were essential for defining many agents of disease, not all pathogenic viruses can be shown to fulfill these criteria.

 Viruses can be described based on their appearance, the hosts they infect, or the nature of their nucleic acid genome.

 All viruses must produce mRNA that can be translated by cellular ribosomes. The Baltimore classification allows relationships among viruses with RNA or DNA genomes to be determined based on the pathway required for mRNA production.

 A common program underlies the propagation of all viruses. This textbook describes that strategy and the similarities and differences in the manner in which different viruses are reproduced, spread, and cause disease.