The correct option is C Syphilis - Trichuris
The virus, which causes the disease is one of a group of viruses, known as arboviruses and are transmitted to humans by insects. Dengue fever is one such unusual arbovirus infection.
Plague is a disease that affects humans and other mammals It is caused by the bacterium, Yersinia pestis.
Trypanosomiasis or sleeping sickness is a parasitic disease of humans and other animals. It is caused by protozoa of the species Trypanosoma.
Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum, while Trichuris is a roundworm, a helminth that causes trichuriasis.
Thus, the correct answer is option (C), 'Syphilis-Trichuris'.