Pink-eye is a name commonly given to an epizootic disease which prevails among horses, and is called by veterinarians Epizootic Cellulites; also Rheumatic Influenza, or sometimes Muco Enteritis. The disease, which of late years has assumed a more virulent form, prevails during a continuance of wet weather, especially when it is also cold, and attacks a number of animals in various parts of a town or district almost simultaneously, thus proving its atmospheric origin; but, although it thus breaks out spontaneously, there is no doubt of its being an infectious disease. The primary symptoms are loss of appetite, dullness, perhaps rigors, with fever, manifested by elevation of the temperature, varying from about 104° to 107°, or, in very severe cases, even 108° F., and acceleration of the pulse. In slight cases the pulse may be 65, in very severe ones over 100 beats per minute. These symptoms are succeeded—but not always—by swelling of the eyelids and redness of the eye—hence the term pink-eye—pain in and stiffness of the limbs, with tumefaction, particularly around the joints. The swellings are at first limited, but soon extend upwards and downwards from the joints affected, and their occurrence gives relief to the pain. The digestive organs are disordered; there is generally constipation at first, the faeces are covered with much mucus, and in many instances there is some degree of colicky or intestinal pain. Some horses have a loud, hoarse cough, at first dry, but often becoming moist; but lung complications are not very common. In some instances the pulse gradually becomes very feeble, though the animal presents no other bad symptoms, the pain having left the limbs, the appetite returning, the swellings diminishing, and the secretions regaining the normal condition; whilst an ordinary observer is confident of a rapid recovery, the animal suddenly dies, and a post-mortem examination reveals the presence of ante-mortem clots of blood in the cavities of the heart, and perhaps in the great pulmonary blood-vessels. To the veterinarian the apparently convalescent stage is a most critical condition, and he must endeavour, by rousing the heart's action, to prevent the formation of these coagula.
As a rule the disease runs its course favourably in from four to ten days, leaving the animal with more or less loss of condition and strength, but both are soon restored by good nursing and gentle exercise. The treatment which has proved most successful is based on the conclusion that the disease runs a definite course, and that all attempts to check this are calculated to do more harm than good. It is most important that all who have the care of horses should know that it is most dangerous to work a horse when this disease prevails after he has manifested the slightest loss of appetite; many horses turned out to work after failure of appetite have been brought back a few hours after in a dying condition. The medicines made use of are those which moderate pain if excessive, keep the contents of the stomach and bowels from undergoing putrefactive fermentation, and act as very slight aperients; and, when the heart's action threatens the condition above described, cardiac stimulants, such as the bicarbonate of ammonia given in a ball. Alcoholic stimulants, in virtue of their irritating properties and their effect on the nervous system, are very injurious, and should not be administered in this nor in any other disease where the so-called fibrinous state of the blood is one of the conditions.