63
troopers on the sick list, besides sixteen grass-cutters' ponies. Fresh cases were daily
discovered.
12. Contagion and infection.—Though I have succeeded in transmitting the
disease by the hypodermic injection of the affected blood, and also by pouring the
blood into the stomach (vide appendices D, E, F, G, and I), I find no evidence
to show that the disease is either contagious or infectious in the ordinary sense;
the weight of evidence is to the contrary, as I have mentioned in appendix K
(paragraph 22), seventy-seven horses of the 3rd Punjab Cavalry becoming affected with
surra at Jutta, from which they all died at Edwardesabad, and did not communicate
the disease to others. It is not improbable, however, that those flies, so excessively
troublesome at Jutta and other outposts, which bite horses so that the blood streams
down the legs as if it had been squirted on—it is not improbable that they do convey
the disease from one horse to another by inoculation. It is a fact that the disease
does spread mostly at those posts where the horses are closely packed, and the flies
are in greatest numbers; but those are the posts also where the drinking water is
worst, so that it is exceedingly difficult to form a true opinion upon this subject
without further experiments. However, the indications at present are that horses
affected with surra should be kept at a distance from other horses during the season
when those flies are common: they were becoming scarce in the early part of October.
I obtained two specimens with difficulty. I do not know yet what is their scientific
name: they are very large, of a brown color, and common in many parts of India;
the natives call them bhura dhang, which means a great needle like sting. There is
a common opinion prevailing among the natives of Dera Ismail Khan district that
this fly is the cause of the disease. I shall refer to this again; but I mention it here
because I think the fly may sometimes propagate the disease by inoculation, and thus
be an item among the causes to account for the spread of the disease more at some
posts, and some years, than others, though the disease would exist independent of
them. When the horses stand close together the fly is able to go from one horse to
another before the blood about its mouth is dry; whereas, if he had to travel some
distance through the dry air in the hot sun, perhaps the virus of the blood would be
destroyed.
13. Different animals affected.—The disease is not confined to horses. I found
two mules affected with it, having the same outward symptoms of surra as horses,
with the specific parasite in the blood. They came into head-quarters from Tank
outpost. The men in charge had not reported them sick, and said they did not know
they were ill. I noticed they were in a much lower condition than another mule
which came in at the same time from the same outpost, On examining the mucous
membranes I found them very yellow with petechiae as in surra horses. There was no
dropsical swelling in either case. The temperature in the rectum of the thinner of the
two was 103, pulse 46. On questioning, I found he had been off his feed to some
extent, irregularly, for a month. The temperature of the other mule was 104, pulse
48 ; had refused one-third of his grain the previous two days. On examining the
blood I found the surra parasites in countless numbers in each drop from both mules.
This illustrates how insidious the disease is in its early stage and how difficult it is to
find from the men in charge when the disease commenced. If those mules had not
been brought into Dera Ismail Khan they would have been made to work as usual
without suspicion of any serious disease though they were becoming thin.
14. I was informed that camels are subject to surra, and that there were several
belonging to the 4th Sikhs suspected to be suffering from it. Upon my application
to Major Growan, commanding the regiment, he was good enough, on the 6th of
October, to send five of them for my inspection, and allowed me to kill two for post-
mortem examination.
Camel No.
„ „
„ „
„ „
„ „
22/79
41/ 79
42/ 79
61/ 80
8/79
aged 8,
„ 7
„ 8
„ 6
„ 1 1
onthe sick list 21 days.
„
„
19
„
„
„ 26 „
„
„
22
„
„
„ over a year.
17