Infectious diseases are caused by pathogens, which include bacteria, fungi, protozoa, worms, viruses, and even infectious proteins called prions. Pathogens of all classes must have mechanisms for entering their host and for evading immediate destruction by the host immune system. Most bacteria are not pathogenic.

What are diseases caused by pathogens?

Pathogens include viruses, bacteria, fungi, and parasites that invade the body and can cause health issues. Anthrax, HIV, Epstein-Barr virus, and the Zika virus, among many others are examples of pathogens that cause serious diseases.

What effects do pathogens have?

A pathogen is an organism that causes disease. Your body is naturally full of microbes. However, these microbes only cause a problem if your immune system is weakened or if they manage to enter a normally sterile part of your body. Pathogens are different and can cause disease upon entering the body.