Volume XI 
NOVEMBER, 1918 
No. 1 
SPIROCHAETA ICTEROHAEMORRHAGIAE IN THE 
COMMON RAT IN ENGLAND. 
WITH REMARKS ON THE MINUTE STRUCTURE OF THESE LEPTOSPIRA (NOGUCHI). 
By ALFRED C. COLES, M.D., D.Sc., F.R.S.E., M.R.C.P. (Lond.). 
Physician to the Royal National Sanatorium , Bournemouth. 
(With Plate I.) 
The Japanese observers Ido, Hoki, Ito and Wani (1916) state that in Infec¬ 
tious Jaundice the infective organism—the Spirochaeta icierohaemorrhayiae 
—is transmitted probably from rats to man by means of the urine of rats, 
directly or indirectly. They say: 
“ We have carefully examined house and ditch rats in the city and rats in 
the coal mines where Weil’s Disease prevails, and found 39*5 % contain 
highly virulent pathogenic spirochaetes in their kidneys. 
“ The kidneys were examined microscopically under dark ground illumina¬ 
tion, and in cases in which we did not find the pathogenic spirochaetes we 
made inoculations into guinea-pigs. 
“ Thus we found S. icterohaemorrhayiae microscopically in kidney or urine 
in 32-4 %, by inoculation in 7 %, making a total of 39-5 % out of a total of 
86 rats.” 
This autumn the same workers (1917) state: “In Japan the rat is undoubt¬ 
edly a carrier of the causal agent of spirochaetosis icterohaemorrhagica. 
Mus decumanus was found to be the carrier in 40-2 % of 149 cases, Mus 
alexandrinus in 0-8 % of 24 cases. 
“In 34 out of 92 cases or 37 % spirochaetes were present in the kidney 
or urine. The organisms cannot be demonstrated in the blood and liver, but 
in the urine of rats harbouring S. icterohaemorrhayiae in the kidney, they were 
present without exception.” 
Finally they state: “On the basis of these findings we conclude that 
1. The extermination of rats and field mice is a highly important prophylactic 
measure against Weil’s Disease. 2. The chemical composition of the soil 
and water plays an important part in the development of S. icterohaemor¬ 
rhayiae and consequently in the spread of the disease of which it is the 
causal agent.” 
In France, Adrian Stokes found much the same thing. In an after note 
to his paper (1917) he says: “Since writing the paper we have been able to 
confirm the statement of the Japanese workers mentioned in the paper with 
Parasitology xi 
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