KEDANI 191 



animals and on domestic animals, especially cattle and horses. 

 Whether some of these animals may be carriers of spotted fever 

 has not been determined. 



Prevention of spotted fever consists primarily in fighting ticks 

 by various methods (see p. 368), and in destroying rodents, both 

 to reduce the number of host animals for the young ticks, and to 

 prevent the possibility of their acting as carriers of the disease. 



There is grave danger that spotted fever may be introduced 

 into other parts of the country where suitable ticks for trans- 

 mitting it can be found. The exportation by railroad of wild 

 deer, elk, goats or other tick-infested animals to zoological parks 

 or government preserves is a dangerous proceeding unless great 

 care is taken to destroy all ticks and to exclude any individuals 

 which might be harboring the disease germ. The occasional 

 occurrence of the disease in various parts of the United States 

 should be carefully watched for, and every precaution taken to 

 prevent local ticks from getting access to the infection. 



Kedani or Japanese Flood Fever. — In certain parts of Japan 

 there occurs a disease usually called kedani, which in many re- 

 spects is reminiscent of American spotted fever. It begins after 

 an incubation of five or six days or longer with a fever and 

 breaking out of the skin, the fever reaching its height between 

 the third and seventh days. It lasts from one to three weeks and 

 is accompanied by a swelling of the lymph glands, especially in 

 the vicinity of the point of infection. This is usually the armpit, 

 neck or groin region, where a small ulcerous wound can be found 

 resulting from the bite of a mite. 



The disease is transmitted by the bite of a very small reddish 

 mite, probably an immature mite of the genus Tromhidium, 

 or harvest bug. These mites live in great numbers on a very 

 abundant local field-mouse, Micromys montehelloi. The mice are 

 not only the hosts of the mites but are also subject to the disease 

 and undoubtedly are an important factor in its distribution and 

 control. Kedani is apparently most common in laborers working 

 in hemp fields in July and August, on the plains which are an- 

 nually flooded by the overflow of certain rivers. 



In Sumatra a similar disease, which is either identical or closely 

 related to kedani, occurs commonly among Chinese and Japanese 

 laborers in the tobacco fields. The disease as it occurs in Su- 

 matra, where it is called pseudo-typhus, differs in some slight 



