Final answer:
Being capable of transmission by direct or indirect contact involves the spread of infectious agents through physical touch or contact with contaminated objects. Contagious diseases can spread through airborne droplets or fomites, and may also involve direct contact like skin-to-skin or oral transmission.
Step-by-step explanation:
Capable of being transmitted by direct or indirect contact refers to the ability of an infectious agent to be spread from one host to another through either physical touch or contact with contaminated objects, known as fomites. For example, highly contagious diseases such as the flu or cold can spread through airborne pathogens when an infected individual's respiratory secretions containing droplets or aerosols are inhaled by others. In contrast, diseases spread by indirect contact transmission, where an infected person may touch an object, leaving pathogens behind, and another individual touches that same object, transferring the pathogens to themselves.
Additionally, direct contact transmission can involve skin-to-skin contact with an infected individual. Pathogens can also be spread through oral transmission, such as by kissing or sharing utensils. Furthermore, other modes of transmission include contact with body fluids of an infected individual, including blood, semen, and saliva, which can occur in various scenarios ranging from IV drug use to sexual transmission.
Ultimately, the spread of infectious diseases is facilitated by close contact and the exchange of bodily secretions, whether via direct contact with an infected individual or indirect contact, such as touching objects contaminated by an infected person's secretions.