Infection Causes, Diagnosis and Treatments

Learn about localized and systemic infections and immune system support.

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  1. What is an Infection?
  2. What Causes Infection?
  3. Diagnosing Infections
  4. Help for Infections

What Is An Infection?

An infection occurs when organisms enter the body, multiply and cause disease. A diverse group of organisms are responsible, including bacteria, viruses, fungi and parasites. When your immune system cannot fight off these organisms, they can cause disease.

According to the Centers for Disease Control and Prevention (CDC), these diseases result in 15.5 million doctor visits each year and 3.7 million emergency room visits.

Most infections are acquired through close contact with infected humans or animals, by drinking contaminated water or from eating undercooked food.

A person is more likely to catch an infection if their body’s resistance is lowered through poor nutrition, lack of sleep, substance abuse, trauma or prolonged exposure to cold temperatures.

There Are Two Types of Infections:

Localized Infections

This occurs in one particular part of the body. The areas affected are often red, tender, swollen and warm. The person may develop a fever and pus may collect at the site.

These can usually be treated at home, but it’s important to care for them properly so they don’t worsen or spread. Some internal localized infections, such as the appendix or the heart, are very serious and require prompt medical attention.

Systemic Infections

This spreads through the bloodstream to the entire body. Symptoms may include shakiness, chills, weakness, nausea, vomiting and joint aches.

These can vary in severity. Some, such as influenza (the flu), often respond well to home treatment. Others, like septicemia and malaria, are life threatening and require urgent medical attention.

What Causes Infection

An infection is caused by microbes spreading and overpowering the immune system:

  • Bacteria. These single celled organisms come in many different shapes and sizes and can cause illnesses including urinary tract infections (UTI), strep through and food poisoning caused by E. coli or salmonella.
  • Viruses. Very infectious tiny organisms, viruses are even smaller than bacteria and can cause illnesses such as influenza (the flu), common cold, chickenpox, HPV (human papillomavirus) and HIV (human immunodeficiency virus).
  • Fungi. This diverse group of organisms includes molds and yeasts that cause conditions such as vaginal yeast infections, athlete’s foot or thrush. Fungi are found in the environment, including outdoors in the soil or indoors in high moisture areas such as bathrooms or locker rooms.
  • Parasites. Parasites live on or in a host organism, getting nutrition at the expense of the host. The three main types of parasites that cause human illness are protozoa, small one-celled organisms; helminths, larger, worm-like organisms; and ectoparasites such as fleas, ticks and lice. Parasites can cause illnesses such as malaria, toxoplasmosis and giardiasis.

These illnesses can be contracted anywhere—through water, air, soil, food, animals, insect bites and contact with an infected person’s blood, skin or mucus.

Diagnosing Infections

Doctors make a diagnosis based on the patient’s physical symptoms, medical history and a physical examination. Some conditions, like the common cold or flu, are easy to diagnose because most people are familiar with the symptoms. For others, doctors may need to perform diagnostic tests.

Tests for Infections:
  • Blood tests to test for antibodies
  • Cultures of samples of blood, urine, other body fluids or material taken from the affected area
  • Spinal tap to examine the cerebrospinal fluid (CSF)
  • X-rays, CT scan, MRI scan and other imaging tests
  • Biopsy of affected tissue
What Are the Symptoms of Infection?

The symptoms vary depending on many factors, including severity, localized or systemic, patient age, other existing medical conditions and overall immune system health.

Common symptoms of infection include:

  • Fever
  • Diarrhea
  • Fatigue
  • Muscle aches
  • Coughing

Help for Infections

Treatment options depend on the type and severity of the illness. Conventional medicine, complementary therapy and natural remedies are highly effective treatments and can be used independently or together.

Usually, the treatment of viruses focuses on symptom relief while your immune system works to clear the disease.

Some viruses are not cleared by the body even after recovery, including herpes simplex virus (HSV) and varicella-zoster virus (VZV), the virus that causes chicken pox and shingles. These viruses remain dormant in the body, but may reactivate years later.

How to Treat an Infection With Conventional Medicine Over-the-Counter (OTC) Drugs

Minor bacterial skin infections often respond well to non-prescription drugs such as benzalkonium chloride or bacitracin.

Prescription Drugs To Fight Infection

Doctors may prescribe antibiotics to treat serious bacterial infections. Antibiotics for bacterial disease come in topical, oral or intravenous form.

Use antibiotics only when appropriate and necessary for a bacterial illness, never for viral infections. Over-use of antibiotics contributes to antibiotic resistance.

Prescription antiviral drugs are used to treat viruses such as herpes simplex, hepatitis C and human immunodeficiency virus (HIV).

How to Use Complementary Therapy
  • Acupuncture
  • Aruyveda
  • Nutritional therapy
  • Meditation
Tips for Reducing Risk of Infection
  • Eat a healthy, balanced diet with all the major food groups.
  • Exercise regularly, which increases your natural killer cell activity that can help prevent illness.
  • Get adequate intake of vitamins such as Vitamin A and C, and zinc.
  • Increase your exposure to fresh air and sunlight each day.
  • Reduce stress by practicing relaxation techniques such as deep breathing exercises, listening to calming music and meditation.
  • Pay attention to your person hygiene and sanitary habits, especially washing your hands.
  • Practice safe sex.
  • Have yourself and your children immunized against infectious diseases, including measles, whooping cough, chicken pox and other common vaccinations.
  • Disinfect wounds and scrapes by washing and covering the wound with a natural antiseptic ointment.
  • Prepare food in sanitary conditions and avoid eating undercooked food.
  • Avoid pets you don’t know or wild animals, and have a doctor examine any bites.
  • Stay home if you’re sick so you don’t spread disease.
  • Cover your mouth or nose during coughs or sneezes.


  1. Seladi-Schulman, J. “Infections: What You Need to Know.” Healthline. Accessed November 5, 2021.
  2. “Infectious diseases.” Mayo Clinic. Accessed November 5, 2021.
  3. “Infection Control.” Centers for Disease Control. Accesssed November 5, 2021.
  4. “Immunization.” World Health Organization. Accessed November 5, 2021.
  5. “NIAID Emerging Infectious Diseases/Pathogens.” NIAID, National Institute of Allergy and Infectious Diseases. Accessed November 5, 2021. 
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