•30 Oct., 1908.] Irif-uenza in Horses. 619 



INFLUENZA IN HORSES. 



S. S. Cameron, 31 .R.C.V .S., Chief Veterinary Officer. 



For anything approaching a parallel to the severe visitation of illness 

 that has befallen the horse population of Melbourne and suburbs during 

 the last few days, the early winter months of 1890 must be re-called. 

 Just as at the present time the human population ig showing a distinct 

 vulnerability to the influenza germ, so about the time in 1890, when the 

 horse epizootic prevailed, it will be remembered that the community was in 

 the throes of the epidemic of what was then called Russian influenza or 

 ■'la grippe." 



The present visitation, however, is apparently more marked, both in 

 the proportion of horses attacked and in the severity of its effect ; and it 

 promises to more closely resemble the historic occurrence of influenza in 

 the Northern States of America in 1872-3, when about a million horses 

 altogether were attacked, and the death rate ran to upwards of 5 per 

 cent. 



Influenza of Horses and Man not Identical. 



It should be made clear that the influenza of man and of horses are 

 not identical, inasmuch as they are not caused by the same germ and are 

 not inter-transmissible from man to the horse and vice versa. The causa- 

 tive agent in the illness of man is a specific germ called Pfeiffer's bacillus, 

 which will not cau.se the disease in horses. While the causal germ of the 

 disease in horses has not as yet been definitely demonstrated, weighty 

 evidence points to its being the cocco-bacillus of Lignieres. Nevertheless, 

 the two diseases are remarkably similar as regards contributory causation, 

 symptoms, progress, corr.plications, and all other features. 



Annual Outbreaks. 



Slight and almost unnoticed outbreaks of influenza in horses would 

 appear to occur every year, the disease apparently smouldering on in city 

 stables from year to year until it breaks out without any very obvious cause 

 into a live, active, and virulently infectious epizootic, such as the present 

 one. No known conditions of temperature, atmosphere, soil, or seasons 

 are associated with the occurrence of an outbreak, but there are certain 

 well-known factors, some of which would appear to have effect as con- 

 tributory causes in connexion with every recrudescence of the disease in 

 virulent form. One of them is the "chill," which is sustained as a 

 result of the sudden vicissitudes of atmospheric temperature prevalent 

 during the autumn and spring months associated as these are with the 

 "change of coat," which is going on at such seasons. The electric 

 tension of the atmosphere associated with the occurrence of thunderstorms 

 has been held to lower animal vitality and so increase susceptibility to 

 attack. In this connexion it is worthy of note that there were several 

 thunderstorms during the second week in September when the outbreak of 

 influenza was first noticed. Exposure to cold and damp situations are 

 potent predisposing causes. Neglect, overwork, and improper feeding also 

 - contribute to an extension of the ravages of the disease. 



