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Bilharziosis in South Africa 
In connection with this it must be remembered that people can 
probably carry the parasites for some considerable time without any 
signs of the disease being apparent, provided they lead a quiet life, but 
the symptoms may at any time appear suddenly in consequence of 
some severe exertion. That the period of incubation according to 
Stock is shorter than that observed by others may be due to the fact 
that the troops in question were cavalry, subject to rough riding; a 
form of exercise most likely to bring on the symptoms at an early date. 
Symptoms. 
Before discussing this portion of the subject, I must state that a 
number of my patients spoke a language understood by no Europeans 
that I know, and by very few natives. Consequently, to obtain any 
account as to how the patient really felt was difficult and to obtain 
anything approaching an accurate history of the cases was impossible. 
But the symptoms I noted do not appear to vary much from those 
reported, as occurring among the inhabitants of other countries. It is 
therefore only necessary to discuss them briefly. 
They appear to vary in severity in different localities. Consider for 
example the case of European and native youths in parts of the 
Transvaal, Natal and Cape Colony, where, though numbers are infected, 
the majority only have a certain amount of haematuria; they may at 
times show evidences of debility, but they are not often really seriously 
incapacitated. On the other hand, among the natives on the East 
Coast and more tropical parts, there is, as stated before, probably no 
disease which causes the inhabitants so much worry as Bilharziosis. 
This may probably be due to there being more than one species of 
parasite; the population of the southern parts are only infected with 
the variety of disease which attacks the urinary system; that of 
northern and tropical parts harbouring both kinds. At the same time, 
it is also possible that the infection in the northern districts may be 
more extensive than in the southern. 
The individual symptoms may be divided into those affecting (1) the 
urinary system ; (2) the intestines. 
Urinary System. 
Haematuria is the most prominent and important symptom of them 
all. 
It occasionally appears suddenly; the result of an accident. I had 
