Hans Zissner has written that epidemics get the blame for defeat while generals get the credit for victory. The final defeat of the Nankai Shitai in Papua in January 1943 can in large part be blamed on sickness. Before this, during the Kokoda campaign, it was the Australians who suffered more from illness than did the Japanese. By the Japanese retreat after Ioribaiwa, at the end of September 1942, the Australians had evacuated 1752 sick from the front line while the Japanese had lost only 343, and this disparity no doubt contributed to the Australian defeats in August and September. The main problem for the Australians was dysentery; for the Japanese it was malaria. In the second half of the mountain campaign, sickness among the Japanese began to rise, exacerbated by the supply crisis, but it was not until mid-November, as the Kokoda campaign concluded, that Japanese medical problems became as bad as those of the Australians.

The Kokoda myth has it in reverse – that on the Kokoda Track Japanese medical casualties were much worse than those of the Australians and that even in early September the condition of the Japanese troops was ‘rapidly deteriorating’. The origin of this error may be an Australian Army report from the first few days of October 1942. As the Australians advanced they found Japanese dead on the track, somewhere between Ioribaiwa and Nauro. The corpses were reported to have no discernible wounds, and it is implied that illness, not starvation, was the cause of death. From this time there appeared in Australian reports frequent mention of Japanese debilitation due to disease. The view that Japanese losses to illness were enormous, even in the early stages of the campaign, was given a boost after the war with the translation of Okada Siezo’s eyewitness account of the trials of the Nankai Shitai. The ever-sensational journalism of Okada suggested there had been ten times the actual number of Japanese medical casualties up to the latter half of September 1942 and that four-fifths of the Japanese force on the Kokoda Track was by then ineffective owing to illness and wounds. Okada’s account is a staple of the Kokoda myth, but it is unreliable and exaggerated.