The disease was then thought to be caused by a slow virus
Markham said, "With current drug therapy, we are able to slow virus
growth but not eradicate HIV infection.
Because researchers are unsure about how to classify them, various names have been ascribed for them, such as slow virus
, virino, viroid, virion and prion, or proteinaceous infectious particle.
In the past, the etiologic agent of transmissible spongiform encephalopathies was believed to be a slow virus
, primarily because of its transmissibility, ability to retain infectivity after filtration, and long incubation period.
Some scientists believe a slow virus
or environmental poison may initiate the disease.