Which of the following is true regarding cultivation and isolation of animal viruses? A. Mouse models are available for virtually all human viral infections and can be routinely used for vaccine development. B. Viruses can be easily grown in liquid culture without any other organisms present. C. The preferred and widely used method of viral isolation and growth is via growth in an embryonated egg. D. Diploid cell culture lines, developed from human embryos, are widely used for culturing viruses that require a human host.

Answer: D.

Explanation:

Viruses can be cultivated within appropriate hosts, such as a living cell. For example, bacteria are grown in an acceptable growth medium to research bacteriophages; then bacteriophagi are added. Within the bacteria, the bacteriophages replicate and greatly increase their numbers.

Diploid cell lines (or strains) are subcultured approximately 100 times before death. A lot more useful in the laboratory and they can be kept in liquid nitrogen forever. The human embryonic fibroblasts are one example of this kind.

As diploid cell line, developed from human embryos have more accurate results and can be stored for longer period of time, they are widely used in cultivation and isolation of viruses that require human hosts.

Hence, the correct option is D.