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Published on: December 4, 2015
SWINE INFLUENZA : V. STUDIES ON CONTAGION
1Department of Animal and Plant Pathology of The Rockefeller Institute for Medical Research, Princeton, N. J.
The Journal of Experimental Medicine
|October 30, 2009
Summary
A swine influenza strain lost contagiousness due to a bacterial change, not the virus. This research identifies the bacterial component as key to swine influenza transmission and disease severity.
Area of Science:
- Veterinary Medicine
- Microbiology
- Infectious Diseases
Background:
- Swine influenza is a contagious respiratory disease affecting pigs.
- The disease is caused by a virus and bacteria, specifically Haemophilus influenzae suis (H. influenzae suis).
- Understanding the etiological factors influencing disease transmission is crucial for control.
Purpose of the Study:
- To investigate the etiological basis for a change in the contagiousness of a swine influenza strain.
- To determine whether the bacterial or viral component is responsible for altered disease transmission.
- To elucidate the role of H. influenzae suis in the pathogenesis of swine influenza.
Main Methods:
- Comparative analysis of a highly contagious and a partially contagious swine influenza strain.
- Experimental infection of swine to assess disease transmission and characteristics.
- Substitution experiments using etiological components (bacterial and viral) from different strains.
Main Results:
- A swine influenza strain shifted from full to partial contagiousness, transmitting only the virus.
- The altered strain caused a mild filtrate disease, not typical swine influenza, upon contact transmission.
- Swine experimentally colonized with H. influenzae suis developed swine influenza after exposure to the altered strain.
- Substitution experiments demonstrated that the bacterial component, not the virus, was responsible for the change in contagiousness.
Conclusions:
- The change in contagiousness of the swine influenza strain was solely due to an alteration in the bacterial component (H. influenzae suis).
- The viral component remained unchanged and was not responsible for the reduced transmission or altered disease phenotype.
- H. influenzae suis plays a critical role in the full expression and transmission of swine influenza.
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