"Friedrich Karl Kleine joined the Prussian Army as a medical officer and came to the Institute for Infectious Diseases in Berlin, headed by Robert Koch, on January 15, 1900. As a medical officer, he took over the management of the infection department at the Institute for Infectious Diseases in 1901. He accompanied Koch from 1906 to 1907 on his research trip on sleeping sickness in German East Africa. He later traveled to the Belgian Congo. In Rhodesia he married his assistant Hanna Okelmann, who had worked as a laboratory assistant at the Koch Institute for years. From 1908 to 1914, Kleine directed the fight against African trypanosomiasis in German East Africa. Initially he worked in the eastern and north-eastern outskirts of Lake Victoria (Mwanza and Musoma). He also repeatedly examined the northwestern area around Bukoba. Finally, Kleine moved his main area of work to the region around Lake Tanganyika because there were clearer signs of the existence of sleeping sickness. In 1911/12 he suggested the establishment of a microbiological institute in the Imperial Hospital (later Ocean Road Hospital and from 1996 "Ocean Road Cancer Institute") in Dar es Salaam, which was also established there in 1912. In April 1914 he took over sleeping sickness research in Cameroon. He was drafted into the protection force and temporarily served as chief physician there. At the same time, he acted as medical advisor to the governorate when the regular job holder Heinrich Werner was taken prisoner by the British. Kleine transferred to the neutral Spanish territory (Rio Muni) together with the command of the protection force in February 1916 and was interned in Madrid until the end of the war. The sleeping sickness researcher Karl Rösener, who was also interned in Spain, also worked with him in Cameroon.
Mostly Friedrich Karl Kleine, like his teacher Robert Koch, worked in the area of Lake Victoria and then in the region around Lake Tanganyika. His closest confidant in matters of sleeping sickness was the former military doctor Max Taute (later professor), who played a major role in researching sleeping sickness in East Africa. Under the guidance of Kleine, the first bacteriological institute was set up at the German hospital in Dar es Salaam in 1912, which, however, lost its importance for tropical medicine during the British colonial period. This old laboratory still exists at today's Ocean Road Cancer Institute as part of German-Tanzanian cancer research and control in Tanzania."