IMMUNOLOGY

Detailed explanation-1: -What is a pathogen? A pathogen is defined as an organism causing disease to its host, with the severity of the disease symptoms referred to as virulence. Pathogens are taxonomically widely diverse and comprise viruses and bacteria as well as unicellular and multicellular eukaryotes.

Detailed explanation-2: -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.

Detailed explanation-3: -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.

Detailed explanation-4: -A pathogen is a living thing that causes disease. Viruses and bacteria can be pathogens, but there are also other types of pathogens. Every single living thing, even bacteria themselves, can get infected with a pathogen.