Ebola and Marburg Viruses: A View of Infection Using Electron Microscopy

Filoviruses (marburgviruses and ebolaviruses) are members of a hazardous group of human pathogens that can be studied only in biological highcontainment facilities. The hemorrhagic fevers they cause cannot be treated specifically, and vaccines are not available. Furthermore, the natural hosts of these viruses remain unidentified. Accordingly, the U.S. Centers for Disease Control and Prevention classifies these viruses in the highest risk group as biosafety level 4 (BSL-4) agents and as potential biowarfare agents. Until recently, only a few BSL-4 facilities globally could conduct experiments on filoviruses, and because of that, few compendia on filoviruses have been published. Dr. Elena I. Ryabchikova is a world-renowned specialist in electron microscopy (EM). She heads the Laboratory of Ultrastructural Investigations and Pathomorphology at SRCVB “Vector” in Novosibirsk, Russia, one of the few existing BSL-4 facilities. With the help of Dr. Barbara B. Saunders-Price, a senior scientist at Battelle Science and Technology International in Aberdeen, Maryland, Dr. Ryabchikova recently published a unique book on her experiments with filoviruses. In contrast to other compendia, this one is not a collection of original scientific articles or of review articles. Instead, Dr. Ryabchikova summarizes her research of the last decade, much of which has either not yet been described in the literature or has been published in Russian scientific journals with limited availability. This exceptional book’s first surprise is found on the cover page, which shows an electron micrograph of a chick embryo infected with Zaire ebolavirus, an infection that has not been reported in the West so far. The book is divided into nine well-organized chapters. It begins with a somewhat loose introduction to the history and taxonomy of filoviruses. However, the outstanding methods section, which follows and outlines the details of all of Dr. Ryabchikova’s experiments, clarifies why this book is an essential addition to the filovirus field, and is especially valuable for Western filovirologists. First, the described marburgvirus experiments were performed with a strain not used in the West. Second, not only green, rhesus, and cynomolgus monkeys but also baboons were used for infection experiments. So far, baboons have not been evaluated as filoviral infection models in the West. Third, in contrast to Western filovirus research, all described experiments were performed with low infectious doses reminiscent of natural outbreak conditions rather than with overwhelming viral challenges, which result in different pathological outcomes. Thus, the book provides new data and insights even to experts in the field. In subsequent chapters, numerous impressive EM and light-microscope histology pictures are used to lead the reader through the complex world of the filoviral life cycle. First, the morphological characteristics of filoviruses are outlined, and it is demonstrated that marburgviruses and ebolaviruses can be easily identified and differentiated by EM, both at the level of virion structure and by the shape of viral inclusion bodies. Then, different possible infection Special Feature