Question

How pathogens cause disease?

Answer 1

A disease-causing and an infectious biological agent is called a pathogen. They come under the category of microorganisms viz, bacteria, virus, fungi, viroid, protozoa, prion, etc. They carry diseases from one person to another.

Complete answer:
The pathogens are also the carriers of the diseases as they carry certain diseases with them that inturn infects the other living organism. A pathogen has the ability to produce toxins, immunosuppression the host, and cause disease in an organism. Pathogenicity is related to the degree of infection the pathogen can cause.
The ability of the microorganisms to cause disease is known as its pathogenicity. Microorganisms express their pathogenicity by means of their degree to cause disease in their host. The measure of pathogenicity is called virulence. Those pathogens that cause disease in a host are the highly virulent pathogens.

Additional information:
-Exposure to a pathogen does not ensure that disease will occur, since a host might be able to protect itself via its immune system from the pathogen.
-The diseases are spread widely due to the carriers as they play an important role in carrying the pathogens.
-When the microorganisms invade the tissue this property is known as the Invasiveness. The degree of the occurrence of the disease in the hosts depends upon the pathogenicity of the microorganisms. While the ability of the microorganisms to release toxins is called the.
-The viruses that are pathogenic in nature have the ability to change their hosts, this ability also depends upon the extent of changing the host. The pathogens tend to cause direct or indirect damages.

Note:
A microorganism can be virulent or avirulent depending on whether it can cause disease to its host. The pathogens can cause more damage to the host if it injures or infects them. The most pathogens in the case of humans are the mosquitoes, flies, etc. They cause several diseases that include malaria, cholera, dengue, etc.