Which of the following is NOT a characteristic of infectious diseases?

Infectious diseases are indeed caused by pathogens (such as bacteria, viruses, fungi, or parasites) and can spread between individuals through various means like direct contact, airborne transmission, or contaminated surfaces. Moreover, many infectious diseases can lead to complications if not treated effectively or if they progress.

Non-treatable conditions, however, are not a defining characteristic of infectious diseases. While some infectious diseases can be difficult to treat or may lead to chronic conditions, many are treatable and curable with appropriate medical intervention. Therefore, labeling infectious diseases as non-treatable is misleading and incorrect, as effective treatments exist for a wide range of these diseases.