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Conjunctivitis of Sheep and Goats in India
existence of rickettsial conjunctivitis in sheep and goats in the Punjab. The present paper outlines
the work undertaken by us on behalf of the Veterinary Investigation Officer, Bihar.
Two goats were used in the test of material received from the January 1941 outbreak of disease
in goats. The left eyeball of each goat was anaesthetised with 1 per cent cocaine solution, the corneal
surface lightly scarified, and a few drops of suspected infective ocular discharge rubbed in. The
disease could not be transmitted and no rickettsiæ were demonstrable in conjunctival films of field
cases, stained Giemsa and Wolbach-Pinkerton. The disease again appeared in sheep in Bihar in
October, 1941, and two sheep were received at Izatnagar as described below.
Sheep 1. This animal was affected with a severe, bilateral conjunctivitis with keratitis and pannus
formation, the cornea of both eyes bulging and being quite opaque. No granulations were seen
within the conjunctivæ of the lids, nor could rickettsiæ be demonstrated within the conjunctival
cells. However, numerous polymorphs and Gram-positive diplococci, many phagocytosed, were
evident in such concentration as to suggest a pure bacterial infection. The animal was destroyed
and both eyes dissected. The anterior chamber contained a few fibrin shreds and the aqueous humour
was slightly cloudy, but neither cells nor organisms could be detected on film examination. The
lens, ciliary body, iris and inner structure of the eye appeared normal, and the vitreous was clear.
Sections of the eyeball taken from the ora serrata of the retinal coat through the ciliary body, iris
and cornea, after formalin fixation and staining by haematoxylin and eosin, showed irido-cyclitis
and interstitial keratitis with intense eosinophilia, strongly suggestive of a parasitic infection. How-
ever, no nematode parasites could be detected in sections stained by Giemsa or Læffler. The vitamin
A liver reserve of this case was within normal limits. With material from this animal, two sheep,
with apparently normal eyes, were inoculated in the anterior chamber of the eye with a few drops
of mixed aqueous-vitreous humour. No reaction occurred in either animal over 85 days of observa-
tion.
Sheep 2. Both eyes were equally affected, the eyeballs bulging, and the cornea cloudy, save at
the margin where pannus-like lesions were noted. No rickettsiæ were observed in Giemsa-stained films
of the conjunctival epithelium, while by Gram's stain polymorphs were seen to be very numerous
with diplococcal organisms similar morphologically to those seen in the first case. Cultures on blood
agar from the conjunctiva, after swabbing with warm normal saline, yielded a Gram-positive dip-
lococcus morphologically similar to the organism seen on direct film examination, and a smooth
strain of Bac. subtilis. Two sheep were inoculated immediately under the bulbar conjunctiva of
the left eye with two drops of a 48-hour serum broth culture of the coccus isolated, which was also
liberally rubbed over the conjunctival surfaces of the same eye. No reaction occurred over a period
of two months. With two other sheep, the bulbar conjunctiva of the left eye was lightly scarified
under cocaine anaesthesia and the ocular discharge from Sheep 2 well rubbed in. Observation over
82 days failed to reveal any lesions. Also, two healthy sheep were kept in close contact in the same
shed with Sheep 2, but neither contracted the disease during 82 days contact; incidentally, flies
were numerous in the shed during this time. During the interval entailed by these transmission
tests in sheep, very considerable improvement occurred in the eyes of Sheep 2, and after about ten
weeks the only visible lesion was some haziness of the cornea and increased vascularity at the corneo-
sclerotic margin; the intra-ocular tension had also abated. This phase was dramatically interrupt-
ed by a sharp and severe attack of conjunctivitis affecting both eyes, but no granulations were seen
within the bulbar or palpebral conjunctivæ. Films from both these surfaces, however, stained by
Giemsa and thionin blue, showed on this occasion unmistakable rickettsiæ within the majority of the
conjunctival cells, either densely packed or disposed in tight clusters within the cytoplasm
(Plate I, fig. I).
The morphology and staining affinities of these organisms corresponded precisely with the original
description of R. conjunctivæ Coles, 1931. At the same time, the signs of bacterial infection, originally
noted in Sheep 2, again came into prominence in addition to the rickettsial infection. We were
disappointed in our further efforts serially to transmit the disease to the eyes of healthy sheep.