PROPHYLAXIS AGAINST EQUINE SURRA                       291

purposes under field conditions, although the records of their own work, as
summarized above, provide useful indications as to the manner in which the drug
might be successfully used for such purposes.

For prophylaxis against dourine, Pfeiler (cited by Ruppert and Edwards),
recommends two doses of 3 grammes each, to be administered at an interval of eight
days during the covering season.

For Mal do Caderas, Migone and Osuna [ 1922 ] recommend a dose of 2
grammes of " Bayer 205 " to be given in physiological salt solution.

Writing about T. venezuelense infection which is reported to kill hundreds of
horses every year in Venezuela, Tejera [ 1924 ] recommends that for prophylaxis
against this disease, 2 grammes of "Bayer 205'' should be injected every six
months.

For prophylaxis against the form of camel trypanosomiasis known as
"su-auru", Emelin and Zeiss [1928] employed a dose of 5 to 10 grammes of
" Bayer 205 ", and they consider doses above 10 grammes as unnecessary. It is of
interest that for curative purposes they employed only 4 grammes, the drug being
injected into the large abdominal vein.

Coming to surra, Yakimoff and his collaborators ( loc. cit.) consider that for
prophylaxis against the disease in camels in the Ural Region during the summer
period, a dose of 6 grammes of " Bayer 205 " should be effective.

Rodenwaldt and Douwes [ 1922 ], speaking of equine surra, recommend that
all animals " which are suspected of being infected " with surra should receive a
prophylactic injection of 1 gramme for every 150 kilogramme body weight, this dose
being repeated every 4 weeks, for the authors believe that by injection of non-toxic
doses of the drug during the first days of the incubation period of surra, it is
possible to inhibit outbreaks of the disease. According to Kligler and Weitzman
[ 1924 ], however, the injection of the drug during incubation cannot be depended
upon for preventing the disease from developing.

According to Bakker [ 1925 ], all horses in the district should be injected with
1 gramme of " Bayer 205" when surra appears amongst these animals and
horses from outside the district should not be admitted for a time unless they also
are inoculated. A single injection should protect for a month and the injected
animals could still be used, so that ordinary business did not suffer.

The results of experiments carried out by Edwards [1926] in India (ante) appeared
to him to warrant the conclusion that " for horses continually exposed to the risk of
natural infection in surra districts the prophylactic administration of the drug
intravenously at the rate of 1 gramme per 1,000 lb. body weight at intervals of a

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