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Feeding of Ticks on Animals for Transmission and Xenodiagnosis in Lyme Disease Research
Published on: August 31, 2013
THE ETIOLOGY OF COLORADO TICK FEVER
L Florio1, M O Stewart, E R Mugrage
1Department of Public Health and Laboratory Diagnosis, University of Colorado School of Medicine, Denver.
Abstract:
1. The infectious agent of Colorado tick fever filtered through 181 mmicro membranes caused infection in hamsters and one volunteer. 2. In five out of seven instances, hamsters were infected initially with serum filtered through 24 mmicro membranes or the tick fever appeared on serial transfer. 3. We could not infect two volunteers with 24 mmicro filtrates, though these filtrates did cause infection in hamsters as shown by development of the fever on serial transfer. In one instance, the serum of the hamsters rendered ill in this way was injected into the volunteer who had remained well after inoculation with the original material and it caused Colorado tick fever. 4. Normal hamster serum was passaged through 10 groups of animals and then two human volunteers were injected with it. They did not come down with Colorado tick fever, although both of them were susceptible to the disease as shown by the fact that they fell ill of it on later inoculation with serum from a natural instance of the disease. 5. The infectious agent of Colorado tick fever passes through 24 mmicro membranes. On this basis, it is classified as a virus.
Insights
The infectious agent causing Colorado tick fever can pass through fine filters, indicating it is a virus. This finding aids in understanding and classifying the virus responsible for this tick-borne illness.
Area of Science:
- Virology
- Infectious Diseases
- Microbiology
Background:
- Colorado tick fever is a significant tick-borne illness.
- Understanding the nature of the infectious agent is crucial for disease control.
Purpose of the Study:
- To determine the physical properties of the Colorado tick fever infectious agent.
- To classify the infectious agent based on its ability to pass through filters.
Main Methods:
- Filtration of infectious serum through membranes of varying pore sizes (181 µm and 24 µm).
- Inoculation of hamsters and human volunteers with filtered serum.
- Serial transfer of infectious material in hamsters.
- Monitoring for the development of Colorado tick fever symptoms.
Main Results:
- The infectious agent passed through 181 µm membranes, causing infection in hamsters and a volunteer.
- The agent also passed through 24 µm membranes, infecting hamsters and causing fever upon serial transfer.
- Human volunteers were not infected by 24 µm filtrates, but hamsters were.
- Infectious hamster serum transmitted the disease to a previously uninfected volunteer.
- Passage through normal hamster serum did not transmit the disease, confirming specificity.
Conclusions:
- The infectious agent of Colorado tick fever passes through 24 µm membranes.
- Based on its filterable nature, the agent is classified as a virus.
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