Lesions in Sheep. The prominent lesions are parenchymatous inflammation of the liver and kidneys, muco-enteritis, enlargement of the spleen, and icterus, with more or less blood extravasation.
The liver is the seat of acute hepatitis. It is usually swollen and abnormally friable, with a yellowish color often as deep as citron. The parts recently attacked exhibit albuminoid infiltration and cloudy swelling, the older lesions show fatty or granular degeneration. These changes exist especially in the hepatic cells, and fatty metamorphosis bears a direct relation to the obesity of the sheep. If the patient has survived the first few days, the liquefied products are absorbed, there is a relative increase of the interstitial connective tissue and the volume of the organ is materially decreased (acute yellow atrophy of the liver, Schütz). In chronic cases, the hypertrophy of the interstitial connective tissue is the most prominent feature, constituting a distinct cirrhoses (fibroid induration) and the atrophy becomes very pronounced while the surface is very irregular and uneven. The gall bladder is distended, and its mucosa congested.
Jaundice, which may be little marked apart from the conjunctiva, is usually shown in the subcutaneous connective tissue, the skin of the abdomen, the omentum and mesentery, but according to Cadeac is never shown in cartilage, bone nor tendon.
The kidneys show parenchymatous inflammation, congestion, swelling which gives a hardness of touch through the resisting fibrous envelope, and often a pervading shade of yellow. The epithelium of the uriniferous tubes is cloudy, turbid and granular and the tubes themselves contain cylindroid casts. The bladder is catarrhal and has been too irritable to contain urine.
The spleen is tumid, soft, reddish gray, and on section shows excess of blood, pulp, and here and there marbling by fibrinous exudate.
The heart is pale, granular, friable, with a tinge of yellow and with a slight citron colored effusion in the pericardium. The cardiac blood is dark and thick but coagulates and brightens in color on exposure to the air.
There is usually some œdema of the lung, larnyx and pia mater.
There are catarrhal lesions of the abomasum and entire intestinal canal with granular degeneration of the epithelium and spots and patches of arborescent congestion and hæmorrhage. The icteric tint is usually distinct.
Prognosis is always grave. Acute cases are almost always fatal. Chronic cases due to eating lupins in which the poison is relatively weak, or a very restricted amount of the more poisonous lupins, may recover. This mortality is very serious in the affected districts 5.8 per cent. of all the sheep of some districts in Pommerania perishing yearly from this affection and entailing the loss of almost the same number of lambs (Von Below-Seleske).
Prevention. Radical prevention can be secured by the exclusion of lupins from the ration. Where this is undesirable the fields that produce poisonous lupins can be ascertained and devoted to the production of other crops. When a crop of lupins has already been produced on a dangerous field the poison may be extracted from the fodder or subjected to the action of an antidote. Fortunately the poison is concentrated on the surface of the lupin and is easily washed off.