There's a book about German colonies with a chapter on the episode:
ISBN 978-3-548-36940-2
pp. 349-366

The East African conflict was apparently a major medical and logistical disaster for both sides. Estimates about dead indigenous porters (forced by both sides) are in the six figure range. Germans lacked anti-Malaria medicine badly, had to produce it with indigenous plants. Raining season created mud trails that made movement extremely tiresome and created horrible lower leg infections.

Overall quite messy, but the performance of the defenders was nevertheless one of the most extreme ones in history.