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Experimental studies on the virus of "Q" fever
Abstract:
The virus isolated by Derrick from cases of fever produces characteristic pathogenic effects on monkeys and mice. A well-defined febrile reaction, during which the blood is infective for guinea-pigs, follows subcutaneous inoculation of virus in the monkey. Mice inoculated intraperitoneally show enlargement of spleen and liver with characteristic histological changes. In sections and smears of infected mouse liver and spleen large numbers of rickettsial organisms are visible. These occur in relatively large intracytoplasmic microcolonies. Inoculation of mouse virus into guinea-pigs and monkeys gives a febrile reaction with a very short incubation period. Cross immunity tests indicate that mouse virus is identical with guinea-pig virus. The virus produces an inapparent infection in albino rats. The virus survives, but does not produce characteristic lesions on the chorio-allantois of the developing egg. The virus is filterable with difficulty through relatively permeable (0.7 mu) gradocol membranes. Agglutination of semi-purified rickettsial suspensions by immune human monkey and guinea-pig sera has been observed; this reaction appears to be specific.
Insights
This study identifies a fever-causing virus that affects monkeys and mice, revealing rickettsial organisms in infected tissues. Cross-immunity tests confirm the virus is identical in mice and guinea pigs.
Area of Science:
- Virology
- Microbiology
- Pathology
Background:
- A novel virus was isolated from fever cases.
- The virus exhibits pathogenic effects in animal models.
Purpose of the Study:
- To characterize the pathogenic effects of a newly isolated fever virus in monkeys and mice.
- To identify the etiological agent responsible for fever and its associated pathological changes.
Main Methods:
- Subcutaneous inoculation of virus in monkeys and intraperitoneal inoculation in mice.
- Histological examination of infected mouse liver and spleen.
- Cross-immunity tests in guinea pigs and monkeys.
- Filtration experiments using gradocol membranes.
- Serological agglutination tests with rickettsial suspensions.
Main Results:
- Monkeys developed a febrile reaction with infective blood for guinea pigs.
- Mice showed enlarged spleen and liver with visible intracytoplasmic rickettsial microcolonies.
- Inoculation into guinea pigs and monkeys resulted in a short incubation period and febrile reaction.
- Cross-immunity tests indicated the mouse and guinea pig viruses are identical.
- Albino rats showed inapparent infection; developing eggs did not show characteristic lesions.
- The virus was difficult to filter through 0.7 mu gradocol membranes.
- Specific agglutination was observed between rickettsial suspensions and immune sera.
Conclusions:
- The isolated virus causes characteristic pathogenic effects in monkeys and mice.
- Rickettsial organisms are identified within infected host tissues.
- The virus demonstrates cross-immunity between mouse and guinea pig models, suggesting identity.
- The virus has specific serological reactivity, aiding in its identification and classification.