4
differed from it sufficiently to warrant his considering them as local varieties of
the same disease.
Steele carefully watched and recorded the symptoms of the disease, confirm-
ing and adding to those previously described by Evans. He communicated the
disease to the mule, pony, dog and monkey, but was unsuccessful in his trials to
inoculate bullocks and goats.
He found that the size of the parasite varies in different cases ; usually 1/6th
the diameter, and 3 to 6 times the length of a red blood corpuscle. In the fresh
state it is an eel-like body; dried and stained it looks like an oxyuris on a small
scale, with a thick portion in its body, and a spiral tail. The body portion tapers
in either direction; anteriorly it terminates rather abruptly and is somewhat
rigid, and there is apparently a hold-fast organ at the blunt extremity. He
describes the movements as being eel-like, lashing and vermiform, less frequently
spiral, and believes the parasite to be a form of spirilloid, closely related to the
spirillum found in relapsing fever in man.
He concludes by defining the disease thus :—Relapsing fever of mules is an
invariably fatal disorder, characterized by the periodical occurrence of attacks of
high fever, during which a special organism, closely resembling that of spirillum
fever of man, is found in the blood. The organism causes dis-organization of the
blood, which is to an extent repaired during the inter-paroxysmal phases, and
thus the patient is usually able to hold up against the disorder for some time.
But anæmic symptoms and lesions gradually accumulate and culminate in death
from exhaustion, plugging of vessels, or gastric perforation as a result of local
atrophy of the stomach. In some cases the symptoms are acute and the ani-
mal succumbs to the height of the fever.
*Gunn, in 1886, reported on an outbreak at Kohat, on the N. W. Fron-
tier among the grass-cutters' ponies, belonging to No. 1 Kohat Mountain
Battery.
He noted the usual symptoms of Surra in the four affected animals.
On microscopical examination of the blood, he observed numerous minute
parasites, somewhat like eels, which appeared to vigorously attack the red
corpuscles; the parasite is not to his mind a spirilloid, nor does it resemble a
nematode or round worm ; the pseudopods described by Evans are really the
margin of the sides " waved." He estimates the total length at about .0003,
and the greatest breadth at .00023 of an inch. He examined the urine of the
four patients microscopically, and states that in three he found parasites, non-
motile and probably dead. As to the mode of contagion, he thinks stagnant
water was the source, for the following reasons;—
A.—Only grass-cutters' ponies were attacked by the disease.
B.—No mule belonging to the Mountain Battery, nor horse from the
Panjab Cavalry became ill of the disease.
C.—The grass which the grass-cutter's ponies bring in is alike eaten by
mules, horses and ponies.
1).—The mules and horses were watered at a stream, which runs from a
mountain spring through the Cantonment of Kohat, and at no other
place.
E.—That the grass-cutter's ponies are watered at any place, pool or other-
wise, which happened to be at hand.
F.—The ponies stand in the same lines and partake of the same grain as
the other animals, and the same system of sanitation appertains
to all mules in the Battery and Regiment.
Experiments.—He inoculated a dog from a pony on the 20th September,
and on the morning of September 24th many parasites were found in the blood.
The following is an abstract of a report by Veterinary-Surgeon C. E. Nuttall,
A.Y.D., on two outbreaks of ' Surra ' at Meerut during the years 1886 and 1887,
* Gunn, Veterinary Surgeon, Army Veterinary Department, Quarterly Journal of Veterinary
Science in India, Volume V, page 235, 1887.