Chapter LXI: Section X: Infectious Diseases (3)

It is well known that both in Germany and the United States outbreaks of pneumonia of a contagious nature attributed to the presence of a bacillus pathogenic to the pigs of those countries are reported to occur. Indeed, contagious pneumonia of swine under the names of schweineseuche in Germany and swine plague in America are regarded as one and the same disease.

In view of the fact that in a large number of cases pneumonia, more or less extensive, sometimes associated with pleurisy, was found among the specimens forwarded to London, it was considered desirable that the departmental committee should institute a series of experiments to decide whether we had in this country a form of pneumonia in the pig which was communicable from one pig to another.

Accordingly a series of bacteriological experiments were conducted by Professor McFadyean with a view to isolate, if possible, a microorganism which would be capable of inducing pneumonia in healthy pigs. A number of diseased lungs, some of which were taken from pigs affected with swine fever, were examined microscopically by him, and, as was to be expected, several organisms were isolated, but they proved to be morphologically and culturally different from the bacillus of swine fever. Inoculations were carried out with these organisms not only subcutaneously but directly into the lung through the walls of the chest, and feeding experiments were also conducted. The results of these experiments were entirely negative; a certain amount of local injury was caused to the lungs at the seat where they had been punctured, but in no case was either pneumonia or swine fever induced.

The experiments have therefore demonstrated that the pneumonia found in the lungs of pigs affected with swine fever is not due to the swine fever bacillus.

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_.

The following is a tabulated list of the principal epidemics so studied and reported to January 1st, 1901:

_Table showing the Principal Epidemics of Hæmorrhagic Septicæmia in Bovines due to_ Bacillus bovisepticus. ┌─────────────────┬─────┬──────────────┬──────────────────────────────┐ │Name of observer.│Year.│ Locality. │ Local or reporter’s name of │ │ │ │ │ disease. │ ├─────────────────┼─────┼──────────────┼──────────────────────────────┤ │Bollinger │1878 │ Germany │Wild und Rinderseuche. │ │Kitt │1885 │ „ │Rinderseuche. │ │Kitt │1887 │ „ │Septikæmia hæmorrhagica. │ │Poels │1886 │ Holland │Septic pleuro-pneumonia of │ │ │ │ │ calves. │ │Oreste et Armanni│1886 │ Italy │Barbone. │ │Jensen │1889 │ Jutland │Rinderseuche. │ │Piot │1889 │ Egypt │Kounnaq. │ │Van Eecke │1890 │ Java │Septichæmia hæmorrhagica. │ │ │1895 │ │ │ │Hubenet │1895 │ „ │ „ „ │ │ │ │ France, │ │ │Galtier │1891 │imported from │Infectious pneumo-enteritis. │ │ │ │ Algiers │ │ │Reischig │1891 │ Hungary │Maladie des buffles ou Angine │ │ │ │ │ Charbonneuse. │ │Bongartz │1892 │ Germany │Wild und Rinderseuche. │ │Jakobi │1892 │ „ │Wildseuche. │ │Buch │1892 │ „ │Hæmorrhagische septikæmia. │ │Güllebeau and │1894 │ „ │Septikæmia hæmorrhagica. │ │ Hess │ │ │ Charbon Blanc. │ │Fischer │1894 │ Dutch Indies │Septichæmia hæmorrhagica. │ │Leclainche │1895 │ France │Pneumo-enteritis. │ │Von Ratz │1896 │ Hungary │Barbonekrankheit. │ │Sanfelice, Loi, │1897 │ Sardinia │ „ │ │ and Malato │ │ │ │ │Bosso │1898 │ Italy │Septicæmia hæmorrhagica. │ │Pease │1898 │British India │Ghotwa or Ghotu. │ │Lignières │1898 │ Argentina │Pasteurellosis bovina. │ │ │ │ │ “Diarrhœa” and “Enteque.” │ │Fenimore │1898 │ Tennessee │Wild and cattle disease. │ └─────────────────┴─────┴──────────────┴──────────────────────────────┘

It may not be out of place to give at this point a short list of the principal infective diseases of definitely known ætiology, with which hæmorrhagic septicæmia in cattle has been, and may readily be, confused:

_Name of disease._ _Diagnostic points._

Anthrax Altered condition of blood, enlarged spleen,
presence of _B. anthracis_, etc.
Black-quarter Usually localised lesion, crepitant tumour,
presence of _B. anthracis symptomatici_.
Septicpneumo-enteritis Due to a spore-bearing
of calves (Galtier) bacillus—“_Pneumobacillus septicus_”—which
grows rapidly on potato.
Septicæmia of calves Due to typhoid-like bacilli.

CONCLUSIONS.

(1.) Eight outbreaks of hæmorrhagic septicæmia in cattle due to _B. bovisepticus_ occurred in Minnesota from August to December, 1900.

(2.) So far as can be determined, the only other outbreak of this disease hitherto published as occurring in America was one near Knoxville, Tenn., in 1898. The foci of the disease have also apparently been present in Texas and the district of Colombia. No relation can be traced between the disease elsewhere and the present outbreaks, nor between any two of the present ones.

(3.) Of 160 animals in the eight herds, sixty-four showed symptoms of the disease, and all such died—a mortality of 40 per cent. of all the animals in the herds, and of 100 per cent. of those showing symptoms.

(4.) The chief symptoms were loss of appetite, fever, stiffness, swelling of the legs and throat, and a black, tarry, or bloody discharge from the bowels. Bloody urine and bloody nasal discharge were present in some cases. Death occurred usually in from six to twenty-four hours after the first appearance of symptoms.

(5.) The chief lesions discovered at autopsy were ecchymoses, and small and large hæmorrhagic areas in the subcutaneous connective tissues, muscles, lymph glands, and throughout the internal organs. The cervical lymph glands, heart muscle, and alimentary canal were most affected. The spleen was not enlarged nor darkened (except after onset of decomposition).

(6.) From the twenty-two animals on which autopsies were made the same bacillus was obtained from all the tissues examined. Where the examination was made immediately after death—nine cases—it was unmixed with any other organism.

(7.) The bacillus was identified as belonging to the hæmorrhagic septicæmia group of Hüppe, best specifically designated as _B. bovisepticus_; and besides causing hæmorrhagic septicæmia in cattle (synonyms—rinderseuche, buffleseuche, barbone, khounnaq, charbon blanc, ghotwa, pasteurellosis bovina, etc.), closely resembles, if, indeed, it is not identical with, the bacilli causing wildseuche, swine plague, schweineseuche, rabbit septicæmia, chicken cholera, grouse disease, duck cholera, etc. The organism was studied in direct coverglass preparations, parallel cultures in and on various media, and by inoculation of animals in which the characteristic lesions were reproduced, and from the tissues of which the inoculated bacilli were recovered in pure culture.

(8.) An attempt was made to immunise cattle by the injection of filtered, and later of the killed, cultures of the bacillus. The chief difficulties met with were in maintaining the virulence of the bacillus on artificial media, and in determining the proper dosage. The experiments were too few, and the results not sufficiently tested to warrant conclusive statements as to the protective value of the inoculations, but it would appear that a fairly high degree of immunity was produced.

(9.) The prompt removal of the dead animals and isolation of sick ones, accompanied by thorough disinfection by fire, carbolic acid, corrosive sublimate, and freshly-slaked lime, apparently served to check each outbreak within a short time after the measures were instituted.