HOST-PARASITE RELATIONS: INTESTINAL PROTOZOA 



ent regions ; it appears to be greater in the tropics than in 

 the temperate zone but not enough greater to account for 

 the much larger number of cHnical cases encountered in 

 the tropics. A fair estimate from all the data available 

 indicates an average rate of infection throughout the 

 world of about lo per cent. 



Three principal solutions have been offered to the 

 question why there is more clinical amoebiasis in the 

 tropics. One is climate, another, lack of sanitation, and 

 the third, more virulent strains. 



Brug (1925) has attempted to establish climate as the 

 responsible factor. Jaeger (1902) reported epidemics of 

 amoebic dysentery in Konigsberg during August to 

 October 1900, and August to September 1901 ; Brug 

 found the greatest number of cases in 1900 to 1901 in 

 the E. Asiatic Expeditionary Corps to be in the late sum- 

 mer; Viereck (1907) records amoebiasis as most abun- 

 dant at Hamburg in 1900 to 1905 in July and August; 

 Woodcock (1918), in the region of the Suez Canal, 

 found August and September to be the two months when 

 amoebic dysentery was most prevalent ; Jouveau-Dubreuil 



(1919) in Setchouan, China, reports the highest inci- 

 dence of the disease from July to September ; Ledingham 



( 1920) found amoebic dysentery most abundant in Meso- 

 potamia during the hotter months; Vallardi (1920) 

 recorded 840 of 1,671 cases among the Italian Expedi- 

 tionary Corps in Macedonia in July; Garin and Lepine 

 (1924) state that near Lyons, France, relapses are most 

 frequent in June and July, and September and October ; 

 and Scott (1924), in Tientsin, noted that fresh cases of 

 amoebic dysentery are rare in winter. Brug adds to these 



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