Report No. 3 on the Origin and Prevalence of Typhoid 
Fever in the District of Columbia (1908).“ 
In 1908, as in 1907,^ our study of the prevalence of typhoid fever 
in the District of Columbia comprised an epidemiological investiga- 
tion of all cases of typhoid fever reported to the District health office 
during the period extending from May 1 to November 1. In both 
years we have made an especial study of the cases reported in this 
period, because typhoid fever in the District of Columbia during 
these six months is much more prevalent than in the other months of 
the year. Usually about 70 per cent of the cases for the whole year 
are reported in this period. 
Front May 1 to November 1, 1908, there were reported 679 cases as 
gainst 675 cases for the corresponding period of 1907. Of the cases in 
the 1908 period 8 were abandoned because no accurate information 
in regard to them could be obtained and 6 were dropped from our 
records because the diagnosis was determined by autopsy or by 
further clinical observation to be incorrect. Deducting these 14 
cases from the 679, there are left 665 cases for consideration in this 
report. 
DIAGNOSIS. 
This year, as in 1907, it was not practicable for us to study the 
cases in clinical detail; but, judging by the histories obtained in fre- 
quent instances, the results of blood cultures, Widal tests, etc., we 
are of the opinion that again some of the cases were incorrectly 
diagnosed and should not have been placed on the records as cases 
of typhoid fever. 
Reasoning along very general lines, after our study of the situation 
in 1907, we presented the view (Hyg. Lab. Bull. 44, Report No. 2, 
p. 12) that the number of cases of typhoid fever in the District of 
Columbia which are unrecognized and not reported exceeds con- 
siderably the number reported as typhoid fever under mistaken 
diagnoses. 
In the summer of 1908 a house-to-house canvass, covering 32 blocks, 
located in different sections of the city, and having a population of 
5,364, was made and not a case of clinical typhoid fever which had 
not been reported as such was discovered. On the other hand, 
« Manuscript submitted for publication April 16, 1909. 
t> Rosenau, M. J.; Lumsden, L. L.; and Kastle, Joseph H.: Report No. 2 on the 
origin and prevalence of typhoid fever in the District of Columbia, 1907. Hyg. Lab. 
Bull. No. 44, May, 1908. 
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