TREATMENT OF EQUINE SURRA IN ASSAM*

                                                BY

            V. R. GOPALAKRISHNAN, G.M.V.C., P.G. (Mukr.)

                    Veterinary Investigation Officer, Assam

                  (Received for publication on 2 January 1940)

THE method of treatment of surra in equines, as followed in Assam,
is described in this paper and a brief review is also made of other
methods of treatment for comparison. It is well known that a great
deal of work has been done on the chemotherapy of equine surra due
to infection with Trypanosma evansi, as the disease causes very heavy mor-
tality. Assam has sustained periodic losses due to infection with this parasite ;
particularly in equines and bovines. The climatic and geographical condi-
tions of Assam would appear to be favourable to the propagation of the
infection.

The province consists of two main valleys—the Brahmaputra and the
Surma. The climate is humid and the rainfall is very high. Large areas
of land, often inundated in rains and floods, consisting of swampy soil mostly
overgrown by weeds and rough grass usually fringe the permanent culti-
vated land. Some of these areas constitute the grazing reserves for large
herds of cattle. In addition, there are numerous hill ranges and vast forest
areas intercepted by riverain and low-lying marshy tracts. So much so the
seasonal occurrence of numerous parasitic infections is quite common. The
incidence of equine surra has been fairly high and as usual in other parts of
India, it is mostly prevalent in the rainy season (vide Table I). During
the season the transmitting agents of surra—Tabanus and Stomoxys flies—
are very numerous. The 'reservoirs' of the infection—cattle, buffaloes
and wild deer, are always there. Therefore it will not be surprising that on
certain occasions extra staff had to be employed to combat the disease breaking
out in enzootic form.

                            METHODS OF TREATMENT

Ever since the disease was known to occur, various attempts at treat-
ment have been made. A variety of drugs have been tried, alone or in com-
bination with others. The most important ones were the preparations of
arsenic [Lingard, 1899 ; Holmes, 1908, 1910] and antimony [Leese, 1910 ;
Cross, 1914, 1920]. The details regarding the treatment of surra with
arsenicals and tartar emetic are too well known to deserve repetition.

A remarkable advance in the chemotherapy of surra was made in India
by the introduction of the form of treatment with Naganol—' Bayer 205 '
[Edwards, 1928]. The routine line of treatment, immediately on micro-
scopical confirmation of the disease, was to inject 50 c.c. of a 10 per cent
solution of ' Bayer 205 ' intravenously, per 1000 lb. body-weight and 20 c.c.
of 0.1 per cent solution intrathecally. Fifteen days afterwards the intra-
thecal dose only was repeated. Again a fortnight later the full intravenous

       *Read at the Indian Science Congress held at Benares in January 1941.

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