Final answer:
A person or animal that has been exposed to a disease is referred to as a 'Contact.' Being a contact means potential exposure to a pathogen but not necessarily developing the disease.
Step-by-step explanation:
The term that refers to a person or animal known or believed to have been exposed to a disease is Contact. This does not necessarily mean the individual will develop the disease, as not all exposure leads to infection. To cause disease, the pathogen must enter the host tissue through a portal of entry, which includes skin, mucous membranes, and parenteral routes.
A carrier is different as it refers to an infected individual who can transmit the pathogen to others, with or without showing symptoms. Infectious diseases can be transmitted by a vector, which is an organism that carries pathogens from one person to another, such as mosquitoes or ticks. Global travel and population density increase the potential for disease transmission, highlighting the importance of understanding these terms and how diseases spread.