What is Slow Viral Infections?
Slow viral infections – a group of viral diseases of humans and animals, characterized by a long incubation period, a peculiarity of damage to organs and tissues, a slow course with a fatal outcome.
The study of slow viral infections is based on many years of research by Sigurdsson (V. Sigurdsson), who published in 1954 data on previously unknown mass diseases of sheep. These diseases were independent nosological forms, however, they had a number of common features: a long incubation period lasting several months or even years; protracted course after the first clinical signs appear; the peculiar nature of histopathological changes in organs and tissues; mandatory death. Since then, these signs serve as a criterion for classifying the disease as a group of slow viral infections. After 3 years, Gaidushek and Zigas (D.S. Gajdusek, V. Zigas) described an unknown disease of the Papuans on Fr. New Guinea with a long-term incubation period, slowly progressive cerebellar ataxia and tremor, degenerative changes only in the central nervous system, always ending in death. The disease was called “kuru” and opened a list of slow viral infections of a person, which is still growing.
On the basis of the discoveries made, an assumption was initially made that a special group of slow viruses existed in nature. However, it was soon established that it was erroneous, firstly, due to the discovery of a number of viruses that cause acute infections (for example, measles, rubella, lymphocytic choriomeningitis, herpes viruses), the ability to also cause slow viral infections, and secondly, due to with the discovery of a typical slow virus infection in the pathogen, the visna virus, the properties (structure, size and chemical composition of virions, features of reproduction in cell cultures) characteristic of a wide range of known viruses.