Difference between Infection and Infestation

Key Difference: Infection is caused by microorganisms or germs like viruses, protozoa and bacteria. They enter the internal body tissues and then multiply disrupting the normal functionality of the cells. On the other hand, infestation refers to the inflection by larger and complex organisms than germs especially arthropods which reproduce on the exterior surfaces of the body. The term infestation is also used to describe the invasion of the gastrointestinal tract by parasitic worms.

Infection and infestation are both somewhat related. Infection and infestation are both capable of causing illness to a person. An infection is caused by germs known as pathogens that cause illness. These germs enter the body and then grow. One can notice the infection by noticing the symptoms like redness, swelling, warmth or pan in the body. The pathogens which cause infections are generally bacteria or viruses.

These pathogens enter into the body and then grow and multiply. The toxins released by these pathogens break down the cells, and thus cause illness and infection. Acne is an example of a common types of infection. Doctors often prescribe antibiotics to fight and kill infections caused by bacteria.

Defense against Infection includes - Intact skin and mucous membranes, nasal passages- cilia, lungs-macrophages, mouth-saliva, eyes-tears, GI tract- acidity of stomach, flora in large intestine, peristalsis, vagina, urethra, etc.

Infestation is also related to infection, as it can also cause illness. However, it deals with bigger and complex type of organisms. Basically, the term is used in two contexts. Firstly, it is used to describe a situation resulted from a large number of insects when they overrun an area. Ants or cockroaches can also cause these infestations in context to an area.

Secondly. An infestation may also occur due to a parasite when it lives inside or on a host. Bed bugs, lice, fleas, etc. can cause this type of infestation. A parasitic worm can cause infestation by being within the body. These works include hookworm and tapeworm.

Many infections are communicable. Infections and infestations can both lead to disease. The main difference between infection and infestation is that infections deal with the growth of infectious agents like germs in the body, whereas infestation is most commonly used in context to arthropods present on the surface of the skin.

Comparison between Infection and Infestation:

	Infection	Infestation
Definition	Infection is caused by microorganisms or germs like viruses, protozoa and bacteria. They enter the internal body tissues and then multiply disrupting the normal functionality of the cell.	Infestation refers to the inflection by larger and complex organisms than germs especially arthropods which reproduce on the exterior surfaces of the body. The term infestation is also used to describe the invasion of the gastrointestinal tract by parasitic worms.
Origin	From Latin word inficere which means to taint	From Latin word infestare which means to attack.
Example	Eye Infections, Parasitic - Mild to severe infections of the eye and its adjacent structures (adnexa) by adult or larval protozoan or metazoan parasites. Herpes simplex eye infection is caused by a type of herpes simplex virus.	Ectoparasitic Infestations - Infestations by parasites which live on the outside of the body of the host. Scabies is caused by a mite (like a tiny insect) called Sarcoptes scabiei.
Commonly caused by	Bacteria, viruses, fungi, parasites, or protozoa	Caused by animals such as arthropods (i.e. mites and ticks), lice, and worms but excluding those caused by protozoa, fungi, and bacteria.
Focus Area	Entry and development of an infectious agent in the body	Lodgment, development and reproduction of arthropods on the surface of the body