An infection occurs when microbes (germs) enter a person’s body or wound and multiply, causing illness, organ or tissue damage, or disease. Sometimes microbes that normally reside harmlessly inside our body without causing problems grow out of control and cause an infection if our immune system is not strong enough to keep them in balance. Some infections can be life-threatening.
What Causes an Infection?
Millions of microbes live on our skin and inside our body, and generally cause little harm. Trillions more live in the environment or on other animals. The most common organisms that can cause infection include:
- Bacteria. These are microscopic, usually single-celled organisms that are food everywhere (ie, in the air, water, soil, or food). Common bacterial infections include acne, pneumonia, bronchitis, and ear infections.
- Viruses. These consist of a nucleic acid molecule in a protein coat, that is only able to multiply within the living cells of a host. Common viral infections include the colds, flu, and herpes
- Fungi. These are multicellular organisms that are free-living in soil or water or form parasitic or symbiotic relationships with plants or animals. Examples of fungal infections include Vaginal thrush and athlete’s foot.
- Parasites. These live in or on an organism of another species and derive nutrients at the host’s expense, such as pinworms or tape worms.
- Prions. These are a type of protein that can trigger normal proteins in the brain to fold abnormally. Some are spread by infected meat products (such as Creutzfeldt-Jakob disease [CJD]).
Normally, your immune system helps protect your body against these invaders. However, cancer, chemotherapy, medications such as steroids, heavy metals, toxins, a poor diet or sleep, and many other health conditions can damage your immune system reducing your ability to fight infection.
What are the Symptoms of an Infection?
Symptoms may vary depending on what part of your body is infected. For example, if a cut in your skin is infected, symptoms typically include redness and swelling around the area and a yellow discharge. Infections in the body generally have more widespread symptoms such as:
- Fever (this is the most common sign)
- Changes in consciousness
- Cough
- Diarrhea
- Eye problems
- Fatigue or tiredness
- Headache
- Nausea or vomiting
- Pain
- Rash
- Redness, soreness, swelling, or a discharge in a certain area
- Runny nose or nasal congestion
- Shortness of breath
- Sore throat or mouth sores
- Stiff neck
- Sweats or chills
- Unusual discharge
- Urinary problems.
Some infections can lead to a potentially life-threatening complication called sepsis.
How is an Infection Treated?
The treatment for infections varies depending on the most likely cause of the infection. For example:
- Antibiotics may be used to treat bacterial infections
- Antifungals may be used to treat fungal infections
- Supportive measures (such as pain relief, decongestants) may be used to treat some viral infections
- Anthelminthics may be used to treat parasitic infections.
For some infections, (such as Prion infections) there is no known treatment.