STUDIES ON THE ETIOLOGY OF PRIMARY ATYPICAL PNEUMONIA : A FILTERABLE AGENT TRANSMISSIBLE TO COTTON RATS, HAMSTERS,
M D Eaton1, G Meiklejohn, W van Herick
1The Research Laboratory of the California State Department of Public Health, Berkeley.
Abstract:
1. A filterable virus from certain cases of primary atypical pneumonia was transmitted to chick embryos by inoculation into the amnion of suspensions of bacteriologically sterile lung tissue or filtered sputum, and three strains were adapted by passage. 2. After intranasal inoculation into cotton rats or hamsters, suspensions of the infected chick embryo tissues produced pulmonary lesions which were similar to those seen after instillation of infective human material. 3. The agent propagated in chick embryos was specifically neutralizable by serum from patients recovered from primary atypical pneumonia and was not neutralized by the acute-phase specimens. 4. Passages of the virus in cotton rats and hamsters gave confusing results because of contamination with latent respiratory agents already present in the animals.
Insights
Researchers identified a filterable virus causing primary atypical pneumonia, successfully transmitting it to chick embryos. This agent, when inoculated into rodents, caused lung lesions and was neutralized by recovered patient serum, confirming its role in the disease.
Area of Science:
- Virology
- Respiratory Medicine
- Infectious Diseases
Background:
- Primary atypical pneumonia (PAP) is a significant respiratory illness.
- The causative agent of PAP has historically been challenging to isolate and characterize.
Purpose of the Study:
- To isolate and identify the viral agent responsible for primary atypical pneumonia.
- To demonstrate the infectivity and pathogenicity of the isolated agent in animal models.
Main Methods:
- Transmission of filtered lung tissue or sputum from PAP patients to chick embryos.
- Intranasal inoculation of infected chick embryo tissues into cotton rats and hamsters.
- Serological neutralization assays using patient sera (acute and convalescent phases).
Main Results:
- A filterable virus was successfully isolated and adapted in chick embryos.
- Inoculation of infected chick embryo material into rodents produced pulmonary lesions resembling human PAP.
- The viral agent was specifically neutralized by convalescent-phase serum from PAP patients, but not by acute-phase serum.
Conclusions:
- A filterable virus is the causative agent of primary atypical pneumonia.
- Chick embryos and rodent models can be used to study this viral agent.
- Serological evidence supports the viral etiology of PAP.
