<P> Operations in New Guinea were impacted by tropical diseases such as malaria, dengue fever, scrub typhus, tropical ulcers, dysentery from a range of causes and fungal infections . Walker observes that the Kokoda Track "starts and ends with malaria". Malarial vectors were substantially absent from the cooler, higher elevations along the track . Most cases observed in these areas were relapses rather than primary infections . The immediate vicinity of Port Moresby is relatively dry . While this tends to mitigate the risk of malaria, significant rates of the disease were observed in troops, mainly militia, sent to New Guinea for defence of the port, leading up to the campaign . The risk from malaria was particularly high for troops operating in the coastal area around the southern end of the track and during the time when the Australian forces had been forced back to Imita ridge . AIF units returning from the Middle East were more aware of the threat this disease posed and arrived with their own supplies of quinine . For these reasons, the disease did not have the same degree of significance or impact on operations as it did at Milne Bay or the subsequent operations at Buna--Gona . </P> <P> Anderson recounts the prevalence of dysentery among Australian troops, while James reports that "more and more (Japanese) succumbed" to diseases, including dysentery, as they withdrew back along the track . Walker attributes enteric infections to poor field hygiene; contaminated and unpurified water; and, a failure to make effective sanitary provisions along the track during the early part of the campaign . He also identifies that a proportion of diarrhoeal disturbances were attributable to the poor diet (particularly the high fat content of tinned beef) rather than infection . </P> <P> The Japanese 17th Army under Lieutenant General Harukichi Hyakutake was a corps - sized command, based at Rabaul, involved in the New Guinea, Guadalcanal, and Solomon Islands campaigns . Following Coral Sea, the 17th Army considered an overland advance on Port Moresby . This was based on pre-war intelligence that a road existed linking it with Kokoda . Initial aerial reconnaissance was inconclusive but plans were made for a reconnaissance in force and to exploit the possibility of an advance along such a route . The 15th Independent Engineer Regiment (less one company) and the South Seas Detachment under Major General Tomitarō Horii were assigned to these tasks . At the time, Horii was unenthusiastic as to the possibility of success, in consideration of the logistical difficulties that would be faced, but he did not press his objection . </P> <P> An advance party, under command of Colonel Yokoyama Yosuke of the 15th Independent Engineer Regiment was to consist of the main force of the regiment, the 1st Battalion of the 144th Infantry Regiment, and the 1st Company, 1st Battalion of the 55th Mountain Artillery Regiment . It also included 500 Korean and Formosan labourers and 2,000 native labourers from Rabaul . A naval force based on the 5th Yokosuka Naval Landing Party was to land at the same time as the advance party and commence construction of an airfield at Buna . Japanese planning proceeded on the premise that an overland assault would occur . </P>

Where did the australian troops spend 4 and a half months training