192 OTHER SPOROZOA 



respects from the typical Japanese disease and has a very much 

 lower fatality. In its incubation period, eruption and general 

 course it resembles spotted fever more closely than does the 

 Japanese disease, and Schueffner, who has worked most with 

 it, thinks it may be transmitted by ticks as well as mites. The 

 disease has also been reported from the Philippines, and about 

 150 cases have been reported in the Malay States. It is not 

 improbable that it will be found to be widely distributed in 

 southeastern Asia, having been incorrectly diagnosed as other 

 diseases. 



The disease germ of kedani lives in the blood of infected people, 

 and while it does not pass through certain filters it has never been 

 discovered with certainty. Ogata has described a mould which 

 he beUeves to be the organism causing kedani, but his results 

 have not been generally accepted. More recently Nagayo and 

 his fellow workers have found a Piroplasma-like organism in the 

 spleen, lymph glands and blood of victims of the disease, and 

 they believe it may prove to be the cause. The incubation period 

 is not known. 



Prevention in the endemic regions obviously consists in avoid- 

 ing mites by skin applications or other means. The extinction 

 of the field-mice and with them most of the mites would un- 

 doubtedly lessen the danger of the disease. 



Chlamydozoa 



The protozoan affinities claimed for the parasites or parasite- 

 like bodies included in the so-called Chlamydozoa is, as said 

 before, doubtful, and new investigations do not, in most cases, 

 tend to substantiate the claim of these structures to considera- 

 tion as animal parasites. A brief account of the parasites or cell 

 inclusions in some of the principal diseases attributed to this group 

 is all that can Ix' givoii here. 



Smallpox and Vaccine. — The youngest forms of the parasite 

 are minute granules or "elementary bodies" measuring about 

 0-5 M ( s 0.0 of a inch) in diameter. As growth takes place 

 the granules increase in number and become surrounded by 

 material which is usuall}^ interpreted as a reaction product of 

 the cell, forming the " Guarnieri bodies " (Fig. 59A). These 

 eventually rupture, liberating the granules to infect new cells. 



