Infecting inoculable, purulent ophthalmia has been reported in the horse (Vermast, Sobornow, Blazekowic, Menard, Möller, Leclainche), in sheep (Repiquet), and in goats (Mathieu). Again Blazekowic found in an infectious ophthalmia of horses, dogs and cats a microbe which was like that of malignant œdema.
The symptoms are those of conjunctivitis with especially free production of pus, and a tendency to chemosis or to follicular inflammation in the depth of the conjunctival sac, with irregular swellings of the lymph bodies. The pus accumulates in the inner canthus, inside the lids and along their margins, and tends to mat them together. The diagnosis depends on the rapidity and severity of the course of the malady, on the depth of the congestion and on the profuse suppuration.
Treatment. Astringent and antiseptic lotions are especially indicated. Mercuric chloride (1 ∶ 5000), boric acid (2 ∶ 100), creolin (1 ∶ 100), salicylic acid (1 ∶ 1000), silver nitrate (1 ∶ 200). It is not however enough that these should be applied externally; they should be freely injected under the lids at all points so as to act on the deepest portions of the conjunctiva, and this should be repeated once or twice daily. Or they may be applied with a soft brush. In a specially virulent outbreak silver nitrate (2 ∶ 100) or pyoktannin (1 ∶ 1000) solution may be used. Setons and blisters, laxatives and cooling diuretics may be employed as in the severe types of simple conjunctivitis.
INFECTIOUS CONJUNCTIVITIS IN HERBIVORA. ENZOOTIC OPHTHALMIA.
Causes: infection, pollen, soil emanation, winter or summer; cases of extension by infection. Cattle, sheep, goats, ponies. Accessory irritants. Symptoms: severe purulent conjunctivitis. Papillary and follicular hypertrophy, uniform redness, protruding head, opacities, erosions, ulcers, photophobia, staphyloma. Treatment: rest, darkness, coolness, elevated head, purgative, diuretics, sedatives; locally solutions of pyoktannin, sublimate, silver nitrate, boric or salicylic acid, atropia, puncture.
Causes. This affection which attacks at once or in rapid succession a large portion or the whole of a herd or flock, is by many held to be infectious while others attribute it to irritant pollen or soil emanation. Its origin from vegetation in flower is held to be supported by its greater frequency in summer than in winter, and the few outbreaks seen in winter are attributed to pollen preserved in the hay. But other things being equal, organized germs are preserved, multiplied and diffused to a greater extent in the hot season so that the origin of the disease from a purely microbian source is at least equally plausible. Certain outbreaks indeed show the transmission of the infection in a most unequivocal manner. A cow suffering from the affection was brought into a stable occupied by a herd previously sound, and in a few days the cow standing next her was attacked, and thereafter a number of others in rapid succession. A small number of cattle from the Buffalo Stock Yards, but which had sore eyes on their arrival in Tompkins Co., N. Y., were placed in a sound herd and the disease spread rapidly to the other members of the herd. Similarly in both sheep and cattle the writer has seen the disease prevail in one herd or flock, while the adjacent herd or flock, separated only by a good stone wall and subject to exactly the same condition of soil, water, exposure, vegetation and pollen has entirely escaped. Kaiser has seen it introduced into a herd by a bull; Fünfstück saw a herd of 300 head attacked in a few days, and Klink 20 out of a herd of 40 head in 14 days. Trumbower has never seen an animal suffer a second time. This is the common experience and would suggest an acquired immunity, yet the comparative rarity of the disease forbids a positive conclusion, without further experience. Menard saw an outbreak among the ponies in the Jardin d’Acclimatation, and as many as fourteen weeks later in the same gardens it attacked the bovine animals.
In sustaining the doctrine of infection, however, we must not altogether ignore accessory causes. Like other affections of the eye, this has seemed to appear especially in low, damp lands, bottom lands, deltas, marshy borders of lakes and level prairies, so that a general lack of tone or a lymphatic constitution may be held to predispose. Nor is it necessary to ignore the influence of pollen, dust and other irritants, which though they may not cause the specific disease, yet prepare the way for its attack by reducing the resisting power of the tissues.
Symptoms. These are the phenomena of severe purulent conjunctivitis. Closed eyes; profuse secretion of tears, sometimes mixed with blood, changing in a few days to a thick, purulent, white or yellow secretion, which collects in masses inside the lids, along their margins, in the inner canthus and on the cheeks, gluing together the cilia, lids and hairs. When separated the lids show a mucosa of an uniform deep red, covered with pus, and irregularly swollen according to the amount of infiltration. Papillary and follicular hypertrophy are marked features, and the nictitans projects excessively over the eyeball. In many cases the cornea becomes opaque and in some instances erosions occur which may cause perforation or loss of the eye. In other instances the ulcers heal with the formation of cicatrices, or the weakened portion of the membrane yields under the internal tension and staphyloma supervenes. In such cases the pupils are contracted.
The disease is usually attended by marked hyperthermia, the secretions, including the lacteal, are materially decreased, appetite and rumination are impaired and the animal leaves the flock or herd. The disease affects cattle and sheep, and Menard and Hoffmann add horses and goats.
Treatment. This must be primarily antiseptic, but without neglecting constitutional disorder. Rest in a dark, cool stall, with the head elevated by tying to a high point. Give at once an active purgative 1½ lb. Glauber salts in 4 quarts warm water, and follow up with cooling diuretics and sedatives (saltpeter ½ oz. and tincture of aconite 20 drops, thrice a day). If the temperature runs very high a few doses of acetanilid or phenacetin may be given. Locally use silver or other antiseptic collyrium.