TRYPANOSOMIASIS. 
about this disease. Notwithstanding that an animal will take his 
food well throughout the disease, he gradually and - steadily loses 
condition and strength. The blood undergoes profound changes, 
thus seriously interfering with proper nutrition of the tissues^ 
Accompanying the debility and prostration of strength, though not 
constant, there may be dropsical swellings which may appear between 
the jaw^s, lower parts of abdomen, chest, or the feet or limbs may be 
swollen. 
When daily observations of the temperature and microscopical 
examinations of the blood can be made it will be found that, even 
with a slight rise or no rise in temperature, trypanosomes may be 
found in the blood. From the notes on cases in my possession the 
temperature rarely rises to 102° F. During intermissions it may 
occasionally be found subnormal. The animals are dull and heavy 
during the paroxysms. 
Diagnosis. — If an elephant be found showing symptoms such as 
described, surra may be suspected ; positive diagnosis however 
depends on the demonstration under the microscope of the trypano- 
some in the blood. It may be necessary to examine blood smears 
daily for some time before a positive diagnosis can be established. 
Incubatioit. — The onset is insidious and the incubation period is 
therefore not definitely settled, authorities having found different 
periods of time to elapse between inoculation and the onset of 
symptoms. The period seems to vary roughly between three and 
thirteen days in the horse. 
Mode of infeciion. — In his "Surra Report, 1899'' Lingard 
states that natural infection may occur in the following ways : — 
(i) By ingestion of grass from lands subject to inundation. 
(ii) By drinking stagnant water. 
(iii) From bites of certain species of flies. 
(iv) The ingestion of corn, etc., contaminated by the excrement 
of rats. 
In 1 90 1 Leonard Rogers pointed out that the horse-flies of 
India were capable of producing the disease in other animals after 
having recently bitten infected animals, and he therefore argues that 
the latent cases in cattle, buffaloes, etc., may thus act as sources of 
infection. 
The flies blamed for the spread of surra belong to the Tabanidae' 
[hmet, ^06) and Stomoxys (yin-ye, oo6g[), though perhaps other 
blood-sucking flies may also carry the disease. 
Duration of disease. — The disease is divided into paroxysms 
and intermissions ; the periods of intermission in the elephant may 
be of considerable duration. The paroxysms last from two to 
several days. ' 
