Introduction

This chapter comprises more or less detailed diagrams of isometric and filamentous viruses of vertebrates, invertebrates, plants, and bacteria. Virology makes extensive use of diagrams for understanding and communicating information. Diagrams are grouped by virus family or grouped in alphabetical order; however, there are a few exceptions to save space. Diagrams are derived from electron micrographs, mainly from negative staining and sectioning of viruses, and a variety of physicochemical, biological, and genetic techniques. Diagrams were selected according to the following, sometimes conflicting, criteria: scientific value and information content, clarity and didactic potential, esthetic appeal, historic interest, diversity, and originality of concept. Vertebrate iridoviruses, due to the presence of lipids in the capsid, and heads of tailed phages often appear swollen or rounded in the electron microscope. Representations of hexagonal capsids, though probably rendering the true shape of these viruses, constitute thus a simplification.