The Cholera outbreak in Borneo had temporarily halted the number of soldiers, equipment, and supplies which the Imperial Japanese Navy transferred to the shores of Brunei, where their primary outpost was located.
The situation in Brunei was absolutely dreadful for the Japanese soldiers, many of which were too ill to even march. Vomit and feces coated the trenches where the Imperial Japanese Army sat back and awaited for medical support, which never arrived.
Morale was at an all-time low for the roughly fifty thousand men who had already deployed to the battlefield. With each passing day, their numbers dwindled as men succumb to the disease, which made their lives a living hell in this tropical environment.