The term 'Sleeping Sickness Carrier' refers to the TSETSE fly, which is a six-letter word. The TSETSE fly is a species of biting fly found in tropical and subtropical regions of Africa. It is the primary vector of the disease known as sleeping sickness, or African trypanosomiasis, which is caused by the protozoan parasite Trypanosoma brucei. The TSETSE fly is responsible for transmitting the parasite to humans and other animals, making it a major public health concern in many parts of Africa.