Final answer:
Viruses are classified according to the ICTV system, which organizes them based on characteristics such as nucleic acid type, shape, and size. The Baltimore classification is another system used based on mRNA production in viruses. The ICTV taxonomy is continually updated to keep pace with new findings and mutations.
Step-by-step explanation:
The system of taxonomy used to classify viruses is based on the guidelines provided by the International Committee on Taxonomy of Viruses (ICTV). This classification system considers various viral characteristics such as type of nucleic acid, shape, and size, rather than relying on a binomial nomenclature. The ICTV classifies viruses into seven orders, 96 families, and 350 genera, with family names ending in -viridae and genus names in -virus. While the Baltimore classification system is also used, it classifies viruses based on how messenger RNA (mRNA) is produced during the virus's replicative cycle, grouping them into seven categories depending on their genome and replication method.
It is acknowledged that classification can be challenging due to the rapid mutation rates of viruses and their diverse evolutionary backgrounds. Nonetheless, the ICTV's universal virus taxonomy has been established to provide consistency in the naming and classification of viruses, although it is constantly evolving to incorporate new discoveries. The ICTV's work also aligns with the International Classification of Diseases (ICD) maintained by the World Health Organization (WHO), connecting viral classification with disease tracking and healthcare administration.