Tsetse fly
His studies of the Tsetse fly led him to believe that the existence of the Hluhluwe-Umfolozi Game Reserve and the Mkhuze Game Reserves in Zululand and the founding of the Kruger Park in the Transvaal lowveld, would create a corridor facilitating the resurgence of the fly from Southern Rhodesia and Portuguese East Africa. Fuller enjoyed the support of prominent veterinarians such as Arnold Theiler and Petrus du Toit.