Infectious diseases can spread through various means, such as air (sneezes and coughs), water, food, insects and vectors. Which one of the following diseases does not have a vector ?

A vector is a living organism that transmits an infectious agent from an infected animal to a human or another animal. Vectors are frequently arthropods, such as mosquitoes, ticks, flies, and fleas. Malaria is a well-known vector-borne disease transmitted by the female Anopheles mosquito. Similarly, Dengue and Zika are transmitted to humans primarily through the bite of infected Aedes aegypti and Aedes albopictus mosquitoes.

AIDS (Acquired Immunodeficiency Syndrome) is caused by the Human Immunodeficiency Virus (HIV). It is transmitted through direct contact with infected body fluids (blood, semen, vaginal secretions, or breast milk). It is not transmitted by mosquitoes or any other biological vectors, as the virus cannot survive or replicate within them.