Human immunodeficiency virus and related retroviruses.

This paper summarizes the current knowledge on the human immunodeficiency virus (HIV) and related retroviruses, describing basic characteristics of this new group of viruses such as morphologic and genetic structure, biological and cultural properties, virus growth characteristics, genetic variability and virus replication. The discovery of new human and simian retroviruses has prompted the World Health Organization (WHO) to convene a group of experts to establish criteria for their characterization. This will allow rapid identification of new variants that may arise and allow public health measures to be implemented accordingly. Different approaches are made to nomenclature in view of the evolution of knowledge about these viruses, and a system of nomenclature has been proposed by the WHO working group. This system, inspired by the one developed for the influenza viruses, is practical and descriptive, providing information on the origins of the organism and its type.