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.
_Locally_ use pyoktannin solution (1 ∶ 1000) or mercuric chloride (1 ∶
5000) injecting under the lids so as to bring it in contact with the
whole diseased surface. A cloth wet with the same solution may be hung
over the eye. Boric acid (1 ∶ 100), salicylic acid (1 ∶ 1000), or silver
nitrate (1 ∶ 100) may be substituted for the above when they seem to be
losing their efficacy.
Ulcers are treated by pyoktannin or silver nitrate solution applied
daily with a soft brush. Keratitis will demand atropia. Abnormal tension
or staphyloma will demand puncture of the cornea. Improvement may be
expected in a few days and recovery in a week or ten days.