LUNG-PLAGUE OF CATTLE. 



487 



lots in the outskirts of large cities. At an 

 early day the infection was carried from Brook- 

 lyn through the dairy herds of New York, Jer- 

 sey City, Newark, Elizabeth, New Brunswick, 

 and Trenton to Germantown and Philadelphia. 

 It extended later to Baltimore, and thence to 

 Georgetown and Alexandria. Its ravages have 

 been confined chiefly to the seaboard, from 

 Long Island to Virginia, and its extension has 

 everywhere been due to the same cause, of the 

 mingling of cattle in uninclosed lands near the 

 cities. The spread has been toward the south, 

 in consequence of a similarity of conditions 

 surrounding cities in that direction which are 

 within easy reach of each other. The disease 

 has frequently been carried into Connecticut, 

 along the line of the New Haven Railroad, but 

 has been uniformly stamped out, through the 

 vigilance of the cattle commissioners of that 

 State. It has never spread north from New 

 York beyond the immediately outlying districts 

 of Westchester and Putnam Counties. This 

 immunity, both in that direction and to the 

 west, is attributed to the absence of cities with 

 open, outlying spaces, and the general use of 

 separate inclosed pasture-grounds. Moreover, 

 the current of the cattle-traffic is almost wholly 

 from the West, eastward over the lines of com- 

 munication to New York. 



Investigation shows that this disease, among 

 American cattle, is due wholly to importation 

 and of spread by infection, and, as it is con- 

 fined thus far to comparatively narrow limits, 

 it might be wholly extirpated, and hereafter 

 kept out by the adoption of proper measures. 

 It is not generated by any of the vicissitudes of 

 weather or climate, by the privations or dis- 

 comforts of travel, by impure air or by feeding 

 on the refuse of distilleries, or glucose and 

 starch factories, but it is aggravated and its 

 ravages facilitated by some of these causes. 

 The fact that it has never been known to exist 

 except when traceable to contagion is a guar- 

 antee that it can be permanently eradicated, 

 but the dangers and difficulties are increasing 

 year by year. In the first place, the cattle- 

 traffic is rapidly increasing. The importation 

 of special breeds is on the increase, and there 

 is a liability, if due precaution is not taken, 

 that diseased specimens may be carried into 

 regions hitherto free from the plague. Should 

 it once get a foothold in the South, where the 

 climate would be favorable to its spread, and 

 especially in the vast unfenced pasturages of 

 the Southwest, it might speedily get beyond 

 control. The increase of the importation of 

 foreign cattle, for breeding purposes, was from 

 5,684 in number, and $415,133.92 in value, in 

 1873, to 21,268 in number, and $1,245,607 in 

 value, in 1881. Efforts to introduce thorough- 

 bred cattle in stock-raising regions, and to im- 

 prove the quality of the great herds of the 

 West and Southwest, suggest a danger of the 

 introduction of this plague, and the need of a 

 systematic policy for its extermination and fu- 

 ture prevention. A trade in Eastern calves, 



sent West from the dairy-farms of New York 

 and Pennsylvania, which has lately sprung up, 

 is also suggestive of danger, and the increased 

 facilities of transportation of cattle creates a 

 growing need of precautions. 



The virus of the lung-plague is very persist- 

 ent and active in a close atmosphere, and is 

 greatly mitigated, if not destroyed, by expos- 

 ure to the open air. It will sometimes develop 

 after a considerable period of quiescence in 

 close places, and is capable of being carried 

 long distances in clothing or other material. 

 It has been communicated by food upon which 

 infected animals have breathed. Mortality 

 from this disease, as well as facility of trans- 

 mission, varies with climate, increasing with 

 an increase of temperature, whether due to 

 latitude or the season of the year. In France 

 it has been shown that about 20 per cent of 

 the cattle exposed to the infection resisted it 

 altogether, and 50 per cent escaped death ; but 

 in South Africa it is no uncommon thing to 

 lose the whole herd if it is once exposed. 

 Losses in England vary from 50 to 60 per 

 cent. In the United States, mortality in- 

 creases with the heat of the climate. The 

 period of incubation of the germs after being 

 taken into the system and before the earliest 

 symptoms of the disease are manifested, varies 

 greatly. It is generally stated as from six to 

 sixty days, but it has been known to extend to 

 ninety or one hundred days, and even longer. 

 This prolonged incubation is an additional 

 source of danger, for an animal that has been 

 exposed may be transported a long distance, 

 carrying the infection with it, before the dis- 

 ease shows itself. The symptoms themselves 

 vary in different countries, climates, and sea- 

 sons, and even different breeds of cattle. Some- 

 times the disease shows itself abruptly and 

 with great violence, and again it develops 

 slowly and insidiously. It usually begins with 

 a cough, at first slight, and noticed only at in- 

 tervals. It may be heard only when the ani- 

 mal rises or drinks cold water. It is usually 

 weak, short, and husky, but may be painful, 

 and accompanied by arching of the back. As 

 the disease advances, the animal grows dull 

 and sluggish, is apt to be found lying alone, 

 apart from the herd, eats and ruminates tardily 

 and breathes more quickly ; the hair, especially 

 about the neck and shoulders, becomes erect 

 and dry, the muzzle has intervals of dryness, the 

 milk diminishes, the eyes lose their prominence 

 and luster, the eyelids and ears droop, the limbs 

 and the roots of the horns become alternately 

 hot and cold. By this time the diseased con- 

 dition of the lungs may be ascertained by per- 

 cussion and auscultation ; the breathing being 

 accompanied by harsh, rasping sounds and 

 more or less exudation of mucus. As seen in 

 America in winter, the violence generally at- 

 tributed to the disease does not appear. The 

 victims fall off rapidly in condition, show a 

 high fever for a time, and the diseased portion 

 of the lung becomes encysted as a dead mass. 



