552 DISEASES OP THE HOKSE. 



Montana, North Dakota, and Texas. It also occurs in Europe, hav- 

 ing been reported in Germany under the name of infectious anemia 

 and in France as infectious typho-anemia. 



Symptoms. — The disease is characterized by a progressive perni- 

 cious anemia, remittent fever, polyuria, and gradual emaciation in 

 spite of a voracious appetite. It begins to manifest itself by a dull, 

 listless appearance and by general weakness, the animal tiring very 

 easily. This stage is followed closely by a staggering, swaying, un- 

 certain gait, the hind legs being mostly affected. There is also noted 

 a weakness and tenderness in the region of the loins, and at the same 

 time the pulse increases in rapidity and may run as high as 70, 

 though weak, stringy, and intermittent. The temperature may rise 

 to 103° F. or higher, remaining high for several days, and then 

 dropping, to rise again at irregular intervals. Toward the end of 

 the disease the temperature occasionally remains persistently high. 

 The horse may improve for a time, but usually this temporary im- 

 provement is followed by a more severe attack than the first. Venous 

 regurgitation is sometimes noticed in the jugular before death. The 

 quantity of urine passed is enormous in some cases. Death finally 

 occurs from exhaustion or syncope. 



The blood shows a slight decrease in the number of white blood 

 cells, while there is a gradual but marked diminution of red cor- 

 puscles, the count running as low as 2,000,000 per cubic millimeter, 

 the normal count being 7,000,000. If the blood is drawn from such 

 an animal, the resulting red clot will be about one-fifth of the amount 

 drawn. Occasionally a slow dripping of blood-tinged serum from 

 the nostrils is observed as a result of this very thin blood oozing 

 from the mucous membranes. Petechias, or small hemorrhagic points, 

 are sometime noticed on the nictitating membrane and conjunctiva 

 of the eye, while paleness of the visible mucous membranes of the 

 nose and mouth is usually in evidence, although they may have a 

 yellow or mahogany tinge. Often a fluctuating, pendulous swelling 

 may appear on the lower lip, point of elbow, sheath, legs, under the 

 belly, or on some other pendant portion, especially late in the disease, 

 which is indicative of poor circulation, thinning of the blood, and 

 consequent loss of capillary action. 



Lesions. — After death the carcass is found to be very emaciated 

 and anemic, the visible mucosa being very pale. This marked absence 

 of adipose tissue makes the skinning of the animal a difficult task. 

 Subcutaneous and intermuscular edema and hemorrhages are frequent- 

 ly observed, although it is remarkable in many cases to see how few 

 macroscopic lesions may be present. The predominating and most 

 constant lesion is probably the petechise, so often observed in the 

 muscle or on the serous membranes of the heart. The heart is gen- 

 erally enlarged and may be the only organ to show' evidence of dis- 



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