Which type of disease can be spread from one person or species to another?

A communicable disease is one that can be transmitted from one person or species to another, typically caused by pathogens such as bacteria, viruses, fungi, or parasites. This type of disease is often spread through direct or indirect contact, respiratory droplets, bodily fluids, or vectors like insects. The ability to spread makes communicable diseases a significant concern in public health, as outbreaks can lead to widespread illness within communities.

Non-communicable diseases, on the other hand, cannot be transmitted between individuals. They are typically chronic conditions that arise from a combination of genetic, environmental, and lifestyle factors, such as heart disease or diabetes. Pathogenic disease refers to illnesses caused by disease-causing organisms, but not all pathogenic diseases are communicable. Chronic diseases are long-lasting conditions that can be either communicable or non-communicable but are often characterized by their duration and the need for long-term management. Therefore, the defining aspect of communicable diseases is their ability to spread from one individual or species to another, which distinguishes them from the other types listed.