The departmental committee arrived at the conclusion that the pneumonia which is occasionally encountered as an independent disease of the pig or in association with swine fever is not ascribable to contagion, but to the presence of organisms which are generally saprophytic in their mode of life, and which only in particular circumstances (such as lowered vitality and diminished resistance on the part of the pig) are able to multiply in the air passages and lung tissue and thus induce pneumonia; and it appeared to the departmental committee that in this country pneumonia of the pig is sporadic and not contagious or epizootic.
CONCLUSIONS.
There is now no reason whatever to believe that there exists at the present time in Great Britain any disease of a contagious nature affecting pigs other than swine fever. The disease of the heart, “verrucous endocarditis,” and the pneumonia which are so frequently met with in pigs cannot be regarded as lesions indicative of an attack of swine fever.
As regards verrucous endocarditis and pneumonia, it may safely be said that they do not exist in England in a contagious form.
Considering all the evidence, it may reasonably be concluded that the departmental committee were correct in their views when they stated that “the evidence obtained during the whole inquiry justifies the conclusion at which they have arrived, viz., that there is no epizootic of swine except swine fever in any part of the United Kingdom which requires to be dealt with under the provisions of the Act of 1894.”
Finally, it may be said that the great factors in perpetuating swine fever will always be pigs which are affected with that disease in the less fatal and unrecognisable form. These animals are constantly distributing the germs of swine fever through their highly infective evacuations wherever they may be taken during the whole period of their illness, and the final extinction of the malady must depend upon the possibility of enforcing measures which will have the effect of preventing the movement of pigs affected with swine fever in this particular form.
HÆMORRHAGIC SEPTICÆMIA IN CATTLE.
In 1902 Drs. Wilson and Brimhall, of the State Board of Health of Minnesota, U.S.A., described under the title of “hæmorrhagic septicæmia of cattle” a widespread infectious disease of bovines which has the following general characteristics:—The disease is distributed the world over, but is apparently most common in low-lying regions, and most general in wet seasons. The animals attacked are of all ages. The onset of the disease is sudden, its course rapid, and its termination usually (90 to 98 per cent.) fatal. Thirty to 90 per cent. of all animals in an infected herd die. The clinical symptoms are refusal of food, cessation of rumination and lactation, initially increased temperature (107° to 109° F.: 42° to 43° C.), rapid, laboured breathing, sometimes bloody discharge from nostrils, bladder, and bowels, and non-crepitant swellings in the throat region, back of shoulders, or about the fetlocks. The most striking pathological lesions are hæmorrhages from 1 millimètre to 20 centimètres in diameter, throughout the subcutaneous, submucous, subserous and intermuscular connective tissue, infiltrating the lymphatic glands, and involving several or all of the internal organs. The spleen is neither enlarged nor darkened. The causative bacteria, which may be isolated from the larger hæmorrhagic areas, lymph glands, heart’s blood, lung, spleen, etc., have the following distinguishing characteristics:
Ovoidal bacilli, with rounded ends of 0·5 to 0·8 microns in transverse diameter, and 1·0 to 1·5 microns in length; sometimes paired and sometimes in chains of three to six individuals. The bacilli in the tissues exhibit polar staining with an unstained “belt” or “middle piece.” They are non-capsulated, non-spore-forming, non-Gramstaining, and non-motile. They grow best aërobically at 98·5° F. (37° C.), though capable of developing anaërobically and at room temperature; prefer the depths rather than the surfaces of media; grow feebly, if at all, on potato; fail to liquefy gelatine; produce acid, but no gas in glucose media, neither acid nor gas in lactose media; and develop varying amounts of indol and phenol in peptone solution. The organisms have been named Bacillus bovisepticus. The lesions of the disease are reproduced in cattle and other animals by inoculation of pure cultures of the organism.
It should be insisted upon that the identification of the disease in a locality in which it has not been previously described, or by veterinarians not having had previous experience therewith, shall take into consideration—(a) the essential clinical symptoms; (b) the pathological lesions as observed before the onset of decomposition; and (c) the morphological and biological identification of the specific bacilli.