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B.—EXTRA-OCULAR FILARIASIS IN EQUINES AND BOVINES.
According to Ercolani, Bartolomeo Grisoni observed filaræ between the eyelids of the ox
as long ago as 1429, but it was only some four hundred years later (1831) that Gurlt publish-
ed the first description of these worms and applied the name Filaria lachrymalis to them. C.
Baillet recognised that the Filaria of the eye-lid of the horse differs somewhat from that of
the ox. At present that of the horse is known as Filaria palpebralis (Wilson), while the one
affecting bovines retains the name given by Gurlt F. lachrymalis.
As certain cases of Extra-Ocular Filariasis have come under my notice during the past
year in the horse and ox, and as according to Neumann ' the filaria of the horses' eye-lids has
rarely been seen, it may be of interest to describe the parasites found affecting equines and
bovines in this country.
HORSE.
History.—In previously reported cases, this filaria appears to have been found in the
great majority of instances, during the process of dissection, and its presence had not been
suspected during life. (Gurlt). Fifty-four of these worms were found post mortem in the two
eyes of a horse by Goubaux, although these organs presented a healthy appearance; there
was, however, a dilitation of the lachrymal canals. In living animals, Kleim and Ralliet have
observed certain symptoms which accompanied the presence of the worm. The former obser-
ver saw ' a horse suffering from epiphora, photophobia, and great tenderness, with persistent
opacity of the cornea,' while, the latter noticed that' the conjunctivitis was accompanied by
slight decortication of the cornea.' Ralliet tried to reproduce the disease in a healthy animal
by placing a female worm full of embryos on the surface of the eye, but without success.
Cobbold, writing in 1879, says 'a species of thread worm (F. lachrymalis) is occasionally
found in the horse between the lids and the eye-ball. It is a comparatively small and harm-
less parasite, the males measuring half an inch and the females two-thirds of an inch. It also
infests the ox. Both the large and small eye worms are viviparous, and, not improbably,
both of them are the means of conveying embryonic filariæ into the circulation. The origin
of these filariæ is unknown.
When travelling along the Saharanpur-Rajpur Dâk road on December 30th, 1897, I
noticed at a changing station, that one of the Dâk ponies presented a marked opacity of the
right cornea (lower half). On questioning the syce, it was ascertained that the affection had
only been present for a period of 12 to 13 days, and that previously the cornea had presented
its ordinary bright and clear appearance. On examination of the eye the above-mentioned
symptoms were found more or less present, but the amount of photophobia was considerably
less than one might have expected to find. After allowing the lachrymal secretion to collect
behind the membrana nictitans, a worm was observed and removed. Further notes of
the case have not been forthcoming, but owing to the degree of opacity present, it is more
than likely that the cornea would never regain its normal condition, even if the cause
of the irritation was removed, but probably other specimens of the parasite were retained.*
The characteristics of the specimen of F. palpebralis examined are as follows:—
Male.—Length 6.3200 mm. Body cylindrical, white in colour, slightly attenuated
at the extremities. The integument is coarsely serrated and finely striated transversely. The
transverse markings at the cephalic extremity are 0.0140 mm. apart; at the junction
of the anterior third, with the middle third, the average 0.0153 mm. apart and on the
posterior third 0.010 mm. The mouth is terminal and nude. Œsophagus straight, 0.441 mm.
in length. Large Intestine tortuous. Anus almost terminal. The tail is slightly curved
forwards, small papillary post-anal projections ; definite pairs of papillæ not observable.
Two unequal spicules, one 0.866 mm. in length, the other 0.152 mm. The former protruding
0.0172 mm. beyond the cloaca, the latter retracted.
Previous observers have given the length of the short and long spicules as 130 and 170
Μ. respectively. In the above mentioned specimen it will be noticed the long spicule has
attained a length five times the length noted.
Bovines.
Filaria lachrymalis (Gurlt, 1831) Synonyms. Thelazia Rhodesü de Blainville, 1828;
F.bovis, 1858; F. palpebrarum Baillet, 1858.
Chaignaud, in a work published in 1827, states that he had seen several epizöotics
amongst bovines at Clarente, in France, caused by the presence of these worms. The conjunc-
tivæ were inflammed, the eye-lids swollen, and there was an abundant flow of tears.
Van Beneden has seen the disease frequently in Belgium. He found the male to measure
from 15 to 20 mm. in length, while the female was slightly larger 20 to 22 mm. In
his experience the worm inhabits the lachrymal duct or the space between the eye-lids and
the ball of the eye, affecting both equines and bovines.
According to Neumann the filaria lachrymalis of the ox appears to have been first seen
by Rhodes of Plaisanse, Gers; it was afterwards referred to by others, Ancize, Seeres,
*Five months later the opacity had almost disappeared.