PROPHYLAXIS AGAINST EQUINE SURRA BY MEANS OF
                                  " BAYER 205 " (NAGANOL).

                             (A REVIEW OF THE LITERATURE.)
                                                   BY
                                        S. K. SEN, M.Sc.,
Assistant Research Officer, Imperial Institute of Veterinary Research, Muktesar.
                    (Received for publication on 3rd September 1931.)

In considering the prophylactic action of " Bayer 205" (Naganol) against
equine surra, it would be profitable also to discuss at relevant points in the fol-
lowing pages the observations recorded by different workers in regard to the pro-
tective value of the drug for surra of camels and bovines and also for certain
other common forms of animal trypanosomiasis, notably, dourine (due to Trypano-
soma equvperdum) and Mal de Caderas (due to T. equinum), for these observations
provide useful indications which might be well utilized for combating surra of
equities. Moreover, whilst, therapeutically, a drug is liable to exhibit considerable
variation in its capacity to ameliorate the clinical symptoms peculiar to each of
these different forms of animal trypanosomiasis, no such variation need be anti-
cipated in regard to its prophylactic action, inasmuch as, for the same species of
animal, such action is merely a matter of the trypanocidal power of the drug in
respect of the species of parasite concerned, so that, provided the minimum
lethal dose of a drug is approximately the same for these species
of trypanosomes, the same scheme of dosage should be suitable for
adoption for prophylaxis against the disease caused by any one of them. As a
matter of fact, some workers, although experimenting with only one species of
trypanosome, have regarded their findings as being applicable also to other species.
Thus, Hesselbach [1922], in the course of a lengthy discussion upon the trypanoci-
dal action of "Bayer 205 " on T. equiperdum, has stressed the importance of his
findings in relation to surra and sleeping sickness. To present the subject in true
perspective, brief mention is also made of the results recorded by various workers
in regard to the prophylactic action of the drug in small animals.

By way of contrast, it is also proposed to make mention of instances where
" Bayer 205 " has been found almost entirely valueless as a prophylactic against
certain forms of trypanosomiasis, such as T. congolense infection, since, as will be
pointed out later; these instances may provide some possible explanation for any
failure on the part of workers in India to use the drug successfully against cases
apparently due to T. evansi.

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