Pleuro-Pneumonia

Pleuro-Pneumonia, or Lung-Plague, a contagious disease peculiar to cattle, generally affecting the lungs and the lining membrane of the chest, producing a particular form of lobar or lobular pleuro-pneumonia, and, in the majority of cases, transmitted by the living diseased animal, or, exceptionally, by mediate contagion. It cannot be communicated to animals other than those of the bovine race. Inoculation of healthy cattle with the fluid from the diseased lungs produces, after a certain interval, characteristic changes at the seat of inoculation, and though it does not develop the lung lesions always observed in natural infection, yet there is a local anatomical similarity or identity. Though numerous investigations have been made, the nature of the infective agent remains doubtful. In 1888 Arloing, of Lyons, described various bacilli obtained from the lesions, but the pathogenic organism of lung-plague has not been discovered.

The earliest notices of this disease testify that it first prevailed in central Europe, and in the 18th century it was present in certain parts of southern Germany, Switzerland and France, and had also appeared in upper Italy. Though Valentine described an epizooty occurring among cattle in 1693 in Hesse, doubts have been entertained as to whether it was this malady. It was not until 1769 that it was definitely described as prevailing in Franche-Comte by the name of "murie." From that date down to 178 9 it appears to have remained more or less limited to the Swiss mountains, the Jura, Dauphine and Vosges, Piedmont and upper Silesia; it showed itself in Champagne and Bourbonnais about the time of the Revolution, when its spread was greatly accelerated by the wars that followed. In the 19th century its diffusion was accurately determined. It invaded Prussia in 1802, and soon spread over north Germany. It was first described as existing in Russia in 182 4; it reached Belgium in 1827, Holland in 1833, the United Kingdom in 1841, Sweden in 1847, Denmark in 1848, Finland in 1850, South Africa in 1854, the United States - Brooklyn in 1843, New Jersey in 1847, Brooklyn again in 1850 and Boston in 1850; it was also carried to Melbourne in 1858, and to New South Wales in 1860; New Zealand and Tasmania received it in 1864, but it was eradicated in both countries by the sanitary measures adopted. It was carried to Asia Minor, and made its presence felt at Damascus. It prevails in various parts of China, India, Africa and Australia, and until quite recently it existed in every country in Europe, except Scandinavia, Holland, Spain and Portugal. In Great Britain cases occurred in 1897.

## Symptoms

The malady lasts from two to three weeks to as many months, the chief symptoms being fever, diminished appetite, a short cough of a peculiar and pathognomonic character, with quickened breathing and pulse, and physical indications of lung and chest disease. Towards the end there is great debility and emaciation, death generally ensuing after hectic fever has set in. Complete recovery is rare.

The pathological changes are generally limited to the chest and its contents, and consist in a peculiar marbled-like appearance of the lungs on section, and fibrinous deposits on the pleural membrane, with oftentimes great effusion into the cavity of the thorax.

Willems of Hasselt (Belgium) in 1852 introduced and practised inoculation as a protective measure for this scourge, employing for this purpose the lymph obtained from a diseased lung. Since that time inoculation has been extensively resorted to, not only in Europe, but also in Australia and South Africa, and its protective value has been generally recognized. When properly performed, and when certain precautions are adopted, it would appear to confer temporary immunity from the disease. The usual seat of inoculation is the extremity of the tail, the virus being introduced beneath the skin by means of a syringe or a worsted thread impregnated with the lymph. Protection against infection can also be secured by subcutaneous or intravenous injection of a culture of Arloing's pneumo-bacillus on Martin's bouillon, and by intravenous injection of the lymph from a diseased lung, or from a subcutaneous lesion produced in a calf by previous inoculation.