A comparative study of the equine abortion and equine influenza viruses.

The research article discusses a comparative study of equine abortion and equine influenza viruses, which suggests that equine virus abortion may be a manifestation of infection of pregnant horses by the equine influenza virus.

Observations and Proposals

• In 1941, Manninger and Csontos observed that equine virus abortion might actually be an infection of pregnant mares by the equine influenza virus. This observation was made based on their experimental findings where mares developed febrile reactions after being injected with infected fetal tissue suspensions, and some developed symptoms similar to equine influenza.
• Another researcher, Kress, reported the occurrence of virus abortion in Austria. He also found a correlation between abortion and bronchopneumonia in eight horses. He suggested that the abortion virus was pneumotropic, indicating a specific affinity to the lungs.

Further Investigations

• In the following years, more observations were made linking equine virus abortions to influenza. In 1944, Kress observed respiratory infections among horses in farms where virus abortions had occurred. Based on these observations, it was suggested that a strain of equine influenza virus was causing the abortions.
• In 1949, Manninger reviewed results of previous experiments. Two horses that had recovered from equine influenza failed to develop a febrile disease after being inoculated with a virus from an aborted fetus’s liver. These findings again pointed towards a link between equine virus abortions and equine influenza.
• A 1951 report by Manninger essentially recapped the findings of earlier publications.

Outbreak of Equine Influenza

• An outbreak of equine influenza that led to the abortion of typically virus-infected fetuses was reported by Hansen. This outbreak supported the theory developed earlier that equine abortion could be caused by the equine influenza virus.

Overall, these studies and observations suggest a significant linkage between equine virus abortions and the equine influenza virus, but more research needs to be done to conclusively establish this relationship.