What is Opportunistic Infection (OI) and How Can It Be Prevented or Treated?

Opportunistic infection (OI) is an infection that is caused by a variety of germs, like viruses, bacteria, fungus, and parasites, that take advantage of a weakened immune system in your body.

Normally, our bodies can control these germs when our immune system is working properly. But when the immune system is weakened, these germs can get out of control and cause serious illness. This is why it is called “opportunistic infection”.

Opportunistic infection is one of the hallmarks of HIV/AIDS. However, opportunistic infection does not only occur in patients with HIV infection. They can occur in anyone who is immune deficient.

Why do people with HIV get opportunistic infection?

Once a person is infected with HIV, the virus begins to multiply and damage CD4 cells, which are white blood cells that fight disease and infection.

When HIV destroys this cell, it becomes harder for the body to fight off infections so that opportunistic infections can develop. If you are HIV-infected and develop opportunistic infections, you might have AIDS, which is the final stage of HIV infection.

What are the most common OIs in people living with HIV/AIDS?

Here are some common opportunistic infections in people living with HIV/AIDS:

1. Tuberculosis (TB)

Tuberculosis is an infection that usually affects the lungs, but it also can affect other parts of the body such as lymph nodes, kidneys, bones, joints, etc. TB is caused by the Mycobacterium tuberculosis bacteria, which can be spread through the air when a person with active TB coughs, sneezes, laughs, or speaks. Symptoms of TB in the lungs include cough, tiredness, weight loss, fever, and night sweats.

2. Cytomegalovirus (CMV)

Cytomegalovirus is a common virus in the herpes virus family. This virus can affect anyone. In a person with HIV/AIDS, CMV infection may involve the lungs, liver, eyes, stomach, and intestines, sometimes it can cause blindness if not treated promptly. Symptoms of CMV include fever, sore throat, fatigue, and swollen glands.

3. Cryptococcal Meningitis

Cryptococcal meningitis is the most common fungal meningitis caused by a fungus known as Cryptococcus neoformans. It is a serious infection of the brain and surrounding membranes that occurs mostly in people with advanced HIV/AIDS, affecting 1-10% of HIV-infected persons. The symptoms include headache, fever, stiff neck, blurred vision, sensitivity to light, personality changes, confusion or hallucinations.

4. Herpes Simplex Virus (HSV)

HSV is a virus that usually affects the skin and mucus membranes. It can sometimes cause more serious infections in other parts of the body.

There are two types of HSV; HSV-1 is the virus infection characterized by the appearance of small blisters on the mouth, eye or lips (cold sores) and HSV-2 is responsible for the majority of genital herpes and is commonly transmitted through sexual contact.

HSV can cause painful cold sores in or around the mouth or around the genitals or anus. In people with severely damaged immune systems, HSV can also cause infection of the bronchus, pneumonia, and esophagitis.

5. Mycobacterium Avium Complex (MAC)

Mycobacterium avium complex is one of the most common type of mycobacterial infection in patients with HIV/AIDS. MAC infection often occurs in the lungs, intestines, bone marrow, liver, and spleen.

The bacteria that cause MAC are M. avium and M. intracellulare. They are found in water, soil, dust, and food. Almost everyone has them in their body. A healthy immune system will control MAC, but people with weakened immune systems can develop MAC.

The symptoms of MAC include high fevers, chills, diarrhea, stomach aches, anemia, and weight loss. When MAC spreads in the body, it can cause blood infections, hepatitis, pneumonia, and other serious problems.

6. Pneumocystis Carinii Pneumonia (PCP)

Pneumocystis carinii pneumonia is a very common lung infection that can be life-threatening if left untreated. This infection is caused by a fungus called Pneumocystis carinii. This parasite is normally harmless in healthy people, but since the parasite remains in the body for life, it can cause disease at any time if the immune system becomes severely damaged, such as in persons with HIV infection.

In addition to the lungs, it also can affect the eyes, ears, skin, liver and other organs. People with this infection may experience fever, fatigue, dry cough and weight loss for weeks or even months. If a person with PCP is not treated, the infection can seriously impair the lungs’ ability to transport oxygen from inhaled air into the blood, which can lead to death.

7. Toxoplasmosis (Toxo)

Toxo is an infection caused by a parasite called toxoplasma gondii. This infection often affects the brain and spinal cord, but it can also affect other parts of the body, including the eyes, heart, lungs, skin, liver, and gastrointestinal (GI) tract. If left untreated, toxo can lead to coma and death.

This parasite is naturally carried by warm-blooded animals such as cats, rodents, and birds and humans can become infected with it by inhaling dust or contacting with cat feces. The parasite is also transmitted through eating undercooked meat, especially pork, lamb, beef.

The first signs of this infection include fever, fatigue, confusion, headache, and tremor, which can last for a month or longer.

How do you prevent opportunistic infections?

Most of the germs that cause OIs are quite common, and you may already be carrying several of these germs. The best way to prevent OIs is to keep your immune system as strong as possible by taking HIV drugs as soon as you know that you are living with HIV. This allows the immune system to fight infections.

People living with HIV can also take the following steps to reduce their risk of getting an OI.

  • Avoid known sources of the germs that cause OIs.
    The germs that can cause OIs can spread from the feces of people or animals. So don’t touch animal or human feces. If you do touch anything contaminated with feces, wash your hands thoroughly with warm, soapy water.
  • Be careful about what you eat and drink.
    Food and water can be contaminated with OI-causing germs. To prevent OIs, don’t eat or drink the following foods:

    • Raw or undercooked eggs, poultry, meat, and seafood (especially raw shellfish).
    • Raw seed sprouts.
    • Unpasteurized milk, cheeses, and fruit juices.
    • Water directly from a lake or river.
  • Get vaccinated.
    Vaccines can be used to prevent certain types of infections such as flu, chicken pox, polio, etc. Infections like pneumonia and the flu can be devastating if you’re HIV positive. Be sure to get regular vaccinations for these and any other infections that your doctor recommends.

  • Practice safe sex.
    Several opportunistic infections are transmitted through sexual contact. Always practice safe sex by using a condom consistently and correctly to prevent exposure to infection.

Can opportunistic infections be treated?

if you develop an opportunistic infection, there are many medicines to treat HIV-related OIs, such antibiotic, antiviral, and antifungal drugs. The type of medicine used depends on the OI a person has.

Once an OI is successfully treated, a person may continue to use the same medicine or an additional medicine to prevent the disease from reoccurring. Make sure to take all prescribed medicine and keep all your follow-up appointments.

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