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64
SURRA.
THIS short notice of surra is written in order to induce R.A.M.C.
officers living in surra districts to assist in filling up a few gaps in
our knowledge of this disease.
It is true that surra is not
human disease, but it is none the
less of very great importance from an Army point of view; as a
force which has to operate in a surra district may lose the greater
part, if not all, its transport and riding animals, with disastrous
results .. Surra generally occurs in hot climates and in low-lying,
damp localities, hence a large number of sick men may be expected
coincidently with the appearance of surra, and the question of transport is certain to furnish a good deal of anxiety for the medical
officer. In this way surra may closely concern us. Moreover,
Leishman's recent observations on the spleens of men dying of
Dum Dum fever suggest the possibility of another trypanosome
disease, in addition to sleeping sickness, occurring in man, so that
any fresh information as to the method of spread of trypanosome
.
diseases in general will be of value.
\ The disease is a parasitic one caused by the Trypanosoma Evansi.
The characteristics of the disease are, progressive wasting and
muscular weakness, associated with irregular fever. The disease
has been known in India for centuries, but its actual cause was only
discovered in 1880 by Evans, a veterinary surgeon.
Distribution.-The information available as to the distribution
of surra is not very extensive, and later researches will probably
show that its epidemic distribution is much more extensive than
is indicated here. The dise'ase usually appears during the rainy
season and disappears gradually with the advent of the cold, dry
weather. The places in which surra is reported to occur annually
are mostly situated close to swamps, or alongside rivers, and are
liable to inundations during the rains.
The accompanying map shows roughly the area in which it has
been reported to occur, although it probably has a much wider
distribution. Lingard says it is confined to a belt lying between
18° and 34° N. Lat.
Susceptible Animals.-The horse and mule are most susceptible
to surra, the dog coming next-these three practically always succumbing to the disease. '1'he camel is supposed to live for three
years after being infected, while the ox generally recovers after
some five or six months.
a
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65
Surra
Infecting Agent. - Lieut.-Col. Bruce, F.R.S., R.A.M.C., has
shown that two other trypanosome diseases,- viz., nagana and sieeping sickness, are transmitted by means of a tsetse fly, the parasite
undergoing no change in the insect, but merely being carried from
an infected to a healthy animal. As nagana closely resembles surra
in its clinical course, and the two parasites are very similar in
appearance, it does not seem unreasonable to suppose that the inDistribution of Surra in India and Burmah.
J.
10
Endemic Area.s-..... -.
Endemic Centres +
Occa.sional outbreaks 0
70
80
fecting agent is also similar. Up to the present no tsetse fly has
been found in India. Rogers made some experiments to see if the
infection is carried by the common horse fly, but the results of his
work rather negative this.
Now, one point we wish to clear up is," What is the infecting
.agent in Surra?" In rats the Trypanosoma Lewisii is said to be
5
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66
Surra
carried by rat fleas; in Nagana the Trypanosoma is carried by
the Glossi'l.la morsitans; in Sleeping Sickness the Trypanosoma
Gambiense (?) is transmitted by Glossina Palpalis; in Dourine the
T'rypanosolna Rougeti is said to be conveyed in the act of coitus.
How is Trypanosoma Evansi carried from the infected to the
healthy animal? We would be greatly obliged to any R.A.M.C.
officer living in a surra district who would try to clear up this point.
In searching for the carrying agent we would suggest that some
such line as the following might be tried :In a surra district try to make out what blood-sucking insects
are present. In nagana there would be no difficulty in determining
which fly is to blame, as the tsetse fly is found in great numbers
in the fly-belt and not outside it. Now, having a suspicion that
a certain fly carries the infection, catch and imprison as many as
possible in small cages made of wood, mosquito netting and glass.
The following drawing represents a cage suitable for this purpose,
and a useful size is 6 x 3i x 3i in. As will be seen from the
drawing five-sides are covered with mosquito netting, and one end
is occupied by a sliding glass door. Through the glass doo't' the
flies can be readily examined.
GLASS
A useful box for taking into the field in which to place the
newly-caught flies may be made something like the following drawing. It is best to make these catching boxes the same size as the
cages to facilitate the transference of the flies. It will be seen from
the drawing that both ends and two of the sides are of wood, one
end is perforated by a hole !-in. in diameter and plugged by a cork.
It is through this hole, of course, that the flies are introduced after
being caught. The other end is a sliding door fixed by a screw
in order that it will not accidentally fall out, and to prevent a native
<;arrier playing with it. When changing the flies from the catching
box to the cage, place the two boxes with the door ends facing each
other, and round the two an indiarubber band; raise the two doors
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67
Surra
but do not pull them quite out, and with a little noise of hitting
the box with your hand the flies will move into the cage.
The flies are most easily caught by means of a small butterfly
net with a diameter of 4 to 5 inches, and having a short handle.
Having secured the flies, do not let them feed for a couple of days.
Then apply the cages to a diseased surra animal, and make a note
of how many flies feed. Keep each cageful of flies unfed for
various periods, say eight hours, twenty-four hours, forty-eight
hours, after which let the flies feed on separate healthy animals, probably dogs would be most easily obtained. The dog's blood must, of
course, be previously examined and found to be free from trypanosomes. The animal experimented on should also be in a healthy
district away from a surra locality, so as to avoid the chance of
infection reaching it by other channels. In Zululand we kept
our animals on the top of a hill and sent down to the low country
at the foot for the flies.
WOODEN
DOOR
The temperature of the animal must be taken twice a day, and
the blood examined frequently for trypanosomes, especially when
any rise of temperature takes place.
Any blood-sucking insects sent to the editor will be examined
and named, and it may be remarked that as blood-sucking flies
other than mosquitoes are becoming daily of more importance, it
would be doing valuable work if our officers stationed all over
India would collect and send here any specimens which occur in
their neighbourhood. A list of such flies could be given in the
Journal with the donor's name opposite. Flies when caught may
be placed in cigarette or other tins, with a little cotton-wool to
prevent damage in transit, and some powdered naphthaline to
preserve them.
•
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Surra
J R Army Med Corps 1904 2: 64-67
doi: 10.1136/jramc-02-01-10
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