What are Infections?

If we want to define an infection it can be defined as the colonization of a host organism by parasite organism.

Parasites that cause infection try to use the resources of the host to reproduce. This mostly results in the host organism getting diseased.

To be more specific, infections are mostly caused by microscopic organisms or microparasites. These microorganisms could be viruses, prions, bacteria, and viroids. However, it is also possible that larger organisms such as macroparasites and fungi can also cause infections.

The normal process of a host to counter these microorganisms from causing an infection is the hosts own immune system.

Hosts that are mammals usually counter infections with a natural response. This response involves inflammation, followed by a healing and thwarting response. We can also use medicine to fight against infections.

When we talk about infections in medicine it comes under the medical branch that is called infectious disease medicine.

It is however difficult to diagnose an infection. This is because specific signs and symptoms that indicate infections are quite rare. Upon suspicion of an infection various tests are carried out on the patient.

The first round of these tests usually includes blood, urine and sputum cultures. To support the diagnostic procedure of an infection chest x-rays and stool analysis may also be carried out. To determine an infection in the brain it is possible that a patient's spinal fluid can also be tested.

There are two main kinds of infections. One is bacterial infection and the other is viral infection.

Both types of infections can cause symptoms such as malaise, fever, and chills. This is why it is very important to differentiate which is the cause of a specific infection. The importance of distinguishing between both infections is also highlighted by the fact that viral infections are not cured by antibiotics, bacterial ones are.

Viral Infection

Generally speaking, viral infections are always systemic. This means that they attack various different parts of the host's body or you can say more than one body system at a time. So in a viral infection you might have a runny nose, sinus congestion, cough, body aches etc. all at the same time. However, there are certain locally affecting viral infections too for example conjunctivitis or "pink eye" and herpes. Pain in viral infections is usually limited to only itchiness or burning and only a few viral infections are painful e.g. herpes.

Bacterial Infection

In bacterial infections we see symptoms such as localized redness, heat, swelling and pain. A main symptom of bacterial infection is local pain i.e. pain in a specific body part. E.g. if a cut is infected by bacteria pain will only be felt at the site of the infection.