Poxvirus Nature of the Motol Virus

In 1958 Kubelka et al reported the isolation of an agent from the pooled sera of 2 brothers hospitalized with infectious hepatitis. The serum mixture was inoculated into the allantoic cavity of chick embryos, and after 4 days incubation the allantoic fluid was inoculated onto monkey kidney cells. A cytopathic agent, termed the Motol virus, was isolated from the tissue culture fluid. The virus produced lethal hepatitis in mice but was not pathogenic for any other host. Kubelka and others have since performed extensive studies in attempts to identify the agent and establish its relationship to infectious hepatitis (Kubelka, 1960, 1964; Schon et al, 1964; Spies, 1965), but the agent has not yet been identified. Attempts to relate Motol virus to mumps virus by demonstrating 4-fold or greater rises in hemadsorption inhibition titer against the agent in human sera during clinical parotitis have been described by Trlifajova et al, 1966. However, these workers noted that the Motol material with which they obtained this data contained 2 agents: a cytopathogenic virus and a noncytopathogenic hemagglutinin-producing agent. They indicated that studies with 5-iododeoxyuridine showed the agents to have different nucleic acids. The noncytopathogenic virus was described as parainfluenza SV5 myxovirus; the cytopathogenic virus was not identified.