What Are Examples of Opportunistic Infections?

Medically Reviewed on 6/17/2022
What Are Examples of Opportunistic Infections
Opportunistic infections can be viral, bacterial, fungal, or parasitic in nature

Opportunistic infections occur in people with weakened or impaired immune systems. When the immune system is compromised, almost any infection can become an opportunistic infection. 

Opportunistic infections can be viral, bacterial, fungal, or parasitic in nature. Here are common examples by category.

What are examples of opportunistic infections caused by viruses?

What are examples of opportunistic infections caused by bacteria?

What are examples of opportunistic infections caused by fungi?

  • Aspergillus: Commonly associated with respiratory infection
  • Candida albicans: Associated with oral thrush and gastrointestinal infection
  • Coccidioides immitis: Causes coccidioidomycosis or Valley Fever
  • Cryptococcus neoformans: Causes cryptococcosis, which can lead to pulmonary infection as well as nervous system infections such as meningitis
  • Histoplasma capsulatum: Causes histoplasmosis and often involves respiratory infection
  • Microsporidia: Can cause microsporidiosis in immunocompromised human hosts
  • Pneumocystis jirovecii or Pneumocystis carinii: Causes pneumocystis pneumonia, a respiratory infection

What are examples of opportunistic infections caused by parasites?

  • Cryptosporidium: Infects the gastrointestinal tract, causing diarrhea
  • Toxoplasma gondii: Causes toxoplasmosis, which is dangerous in unborn babies if pregnant women are infected

What are common signs and symptoms of opportunistic infections?

Symptoms of opportunistic infections vary depending on the organ and the pathogen involved and may include:


Bacterial Infections 101: Types, Symptoms, and Treatments See Slideshow

What are common causes and risk factors of opportunistic infections?

People with weakened immune systems, including those with human immunodeficiency virus (HIV), are more likely to contract opportunistic infections.

The immune system defends the body against potentially harmful pathogens, such as allergies and infections. White blood cells are the most important component of a healthy immune system. A low white blood cell count can be caused by a variety of factors, including medications, infection, and certain diseases. Individuals may be unable to fight illnesses if their white blood cell count is low, leading to opportunistic infections.

Common sources of pathogens that cause opportunistic infections include:

  • Untreated water or soil
  • Unwashed foods, undercooked eggs or meat, unpasteurized dairy or juices, or raw, sprouted grains
  • Contact with the bodily fluids of infected individuals
  • Contact with animal feces

Risk factors for opportunistic infections include:

Common disturbance of the host immunity that may lead to opportunistic infections include:

  • Administration of immunosuppressants or steroid therapy
  • Advanced HIV
  • Chemotherapy
  • Skin injuries (surgery)
  • Antibiotic use resulting in the disruption of the normal flora in the body

How are opportunistic infections prevented?

If you acquire an opportunistic infection, there are antiviral, antibiotic, and antifungal medications that can help. After effectively treating an opportunistic infection, you may continue to use the same or a different drug to keep the infection from recurring.

Prevention tips for opportunistic infections include:

Safe food preparation

  • Some illnesses can enter your body through the food and water you consume.
  • Do not consume raw milk or cheese, raw fruit juices, or raw seed sprouts.
  • Avoid drinking water from lakes and rivers.
  • Use bottled water wherever possible.

Caution around animals

  • Make sure that your pets are vaccinated and that your cat stays indoors.
  • After touching animals, wash your hands.
  • When changing cat litter, use gloves.
  • When working in soil, stay away from animal excrement.

Caution around people

  • Stay away from sick people, especially those with diseases such as pneumonia or tuberculosis.
  • Wipe down exercise equipment using your own towel.
  • Never share needles with other people.
  • Practice good sexual hygiene.
  • Wear masks and gloves when going outside.
  • Keep up with doctor appointments, vaccinations, and immunizations.

Working closely with your doctor and taking reasonable measures can help you lower your risk of opportunistic infections.

Health Solutions From Our Sponsors

Medically Reviewed on 6/17/2022
Image Source: iStock image

HIV and Opportunistic Infections, Confections, and Conditions: https://hivinfo.nih.gov/understanding-hiv/fact-sheets/what-opportunistic-infection

What Are Opportunistic Infection: https://www.thewellproject.org/hiv-information/what-are-opportunistic-infections