Final answer:
Contagious diseases are communicable and can be easily transmitted from person to person, as seen in illnesses like measles, colds, and influenza. They are caused by various pathogens, which are spread through different methods such as coughing or sneezing.
Step-by-step explanation:
Contagious diseases can be transmitted from one person to another; examples include measles, colds, and influenza. These forms of illness are also referred to as infectious diseases, which are caused by the direct effect of pathogens. Pathogens can be cellular, such as bacteria, parasites, and fungi, or acellular, such as viruses, viroids, and prions. A communicable disease that can be easily transmitted from person to person is classified as a contagious disease. Diseases like pertussis and measles are known to spread quickly through populations due to their highly infectious nature.
While some diseases are communicable, others are non-communicable and may be chronic, genetic, or autoimmune. Chronic diseases such as type 1 diabetes or cardiovascular diseases are long-term and may affect individuals throughout their lifetime. Genetic diseases like sickle cell anemia are inherited, while autoimmune diseases involve the body's immune system mistakenly attacking its own tissues.
In the context of the student's question, contagious diseases such as measles, colds, and influenza are easily spread from one individual to another, typically through coughing, sneezing, or close personal contact.