Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at December 18, 2015

In general terms, infection refers to the invasion and reproduction of microorganisms (such as bacteria, viruses, and parasites) that are typically not found in the body. A person who has an infection basically has another organism, or "germ", living inside their body, which will steal nutrients from the host's body in order to thrive. The germs colonize inside the individual's body and begin to reproduce rapidly. The infection may or may not be obvious to the naked eye; it may or may not produce symptoms; and it may or may not remain localized to one particular area of the body.


Definition & Facts

An infection is an invasion and subsequent multiplication of germs within the body's tissue and the reaction of the host tissues to the microorganisms and the toxins they release. It may or may not produce symptoms. The germs may appear anywhere in the body and are caused by infectious agents including bacteria, viruses, fungi, and yeast.

An infection may or may not be visibly obvious, and it is sometimes a result of a local injury to the cells. Some remain localized, while others persist and spread to other areas of the body to become an acute, subacute, or chronic clinical infection or disease. In cases where the microorganisms reach the lymphatic or vascular systems, the infection may become systemic, which means it affects the entire body.

There are numerous types of infection, some of which are more specific than others. Some of the most common types include:

Also worth noting is that it is only considered an infection if the colonization of germs harms the host. In some cases, the growth of bacteria is normal, such as with the presence of bacterial flora in the intestines, which causes no harm to the body.

Symptoms & Complaints

Many symptoms and complaints are associated with infection. The symptoms experienced will depend upon the type of infection that is present.

Common symptoms associated with viral infections (these are systemic infections, and may affect several parts of the body at once):

Many viral infections that produce pain also cause the patient's skin to itch or burn.

Symptoms commonly associated with bacterial infections (usually localized) include:


Nobody is immune to developping an infection from time to time, but usually, our bodies fight them off quickly to protect us from danger. Some people, however, experience chronic and persistent infections. Usually, these infections are caused by viruses (known as viral infections), most commonly hepatitis and herpes. Individuals can become infected by inhaling the virus, sexual contact, or being bitten by infected parasites or insects.

Diabetes patients (or anyone with a weakened immune system, such as those with HIV/AIDS or patients receiving chemotherapy) are also at a higher risk of developing chronic bacterial infections.

Alternately, there are also several medications and/or substances that are capable of causing infections, and sometimes drug interactions can also contribute to their onset.

Some of the common medications known to cause infections include:

  • Ervevax
  • Pluserix
  • Olanzapine
  • HMS Liquifilm
  • and many more!

When combined, certain combinations of drugs, medications, toxins or substances can cause infections.

Common drug interactions that could possibly cause infection include:

Individuals are advised to always tell their doctor about any medications or treatments they are currently using, including prescription medicines, over-the-counter products, supplements, and herbal or alternative treatments.

Diagnosis & Tests

Because some infections have more serious implications than others, it is important to consult with a doctor any time an infection in suspected so that they can properly diagnose the infection and order the appropriate course of treatment. Some infections clear up on their own (as in instances where there are two microorganisms living within the same host that fight each other instead of harming the host), while others require treatment.

If left untreated, certain infections can be life-threatening. An example of this would be a COPD patient who develops a respiratory infection, which could progress into pneumonia (which can be fatal if left untreated).

The patient will first be examined and all symptoms should be mentioned in order to provide an accurate description of the problem. The physician may perform one or multiple diagnostic tests, which could include urine tests, blood tests, swabs, pathology testing, and many more diagnostic tests.

Treatment & Therapy

Once the infection has been identified the physician will determine the necessary plan of treatment. Depending on the type of infection, this could include the use of certain prescription or over-the-counter medications (examples include antifungal medications to treat a yeast infection and an antibiotic for treatment of a vaginal infection), which are typically available as creams, ointments, tablets, and suppositories.

The medication may be a single-use medicine or something that must be taken regularly over the course of several days. Some infections also require some form of physical therapy (short-course vaginal therapy for treating vaginal infections is one example).

Prevention & Prophylaxis

Though is not entirely possible to prevent all infections, many can be avoided by taking a few simple precautionary steps.

These include:

  • Adopting good basic hygiene habits, such as regular hand-washing with soap and warm water, staying hydrated, and avoiding large crowds of people where germs are sure to be running rampant are all helpful ways to prevent the spreading of infection.
  • Avoid sharing personal items, such as toothbrushes, combs, and razors.
  • Cover your mouth and/or nose when coughing or sneezing to prevent spreading the infection to others. Keep tissues handy. Throw out used tissues and wash hands thoroughly with soap and warm water after coming into contact with used tissues.
  • Before coming in to contact with health providers, make sure they have washed their hands or that they are wearing gloves.
  • When sick, avoid close contact with others to prevent the spreading of germs.

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