What Is a Viral Infection?
Viral infections have been compared to parasites. In this condition, a virus attacks your body’s cells to reproduce and survive. Here's what you should know.
Think of a viral infection as a parasite. In this case, the virus attacks your body’s cells to reproduce and survive. In the process, the infection damages and destroys healthy cells, making you ill.
What is a viral infection?
Viral infections are small germs that cause infectious diseases such as common colds, the flu, and warts. More severe cases cause HIV/AIDS, smallpox, and Ebola.
Viral infection points of attack are in the cells found in your respiratory system, throat, and liver. It’s not always dire because, when you get a viral infection, your immune system often kicks in and successfully fights it.
Viral infections can cause a viral upper respiratory infection, another term for a common cold. Upper respiratory infections (URIs) are contagious and occur in your upper respiratory tract, which includes your nose, throat, pharynx, larynx, and bronchi. Other types of upper respiratory infections include sinusitis, pharyngitis, epiglottitus, and tracheobronchitis.
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Symptoms of an upper respiratory infection vary. If the virus is in your respiratory system, it can affect your lungs, nose, and throat. Viral infections are contagious and are usually spread when you inhale droplets that contain virus particles. You can catch the virus if an infected person:
- Sneezes
- Coughs
- Has a cold and shares food with you
- Kisses you
- Touches your hand
Symptoms of an upper respiratory infection include:
- Sneezing, congestion, and runny nose
- Coughing
- Sore throat or hoarseness
- Mild headache
- Body aches
- Fatigue
- Fever
The virus can also cause lower respiratory infections like pneumonia and bronchiolitis, a common lung infection in young children and infants that starts off like a common cold and can progress to coughing, wheezing, and sometimes difficulty breathing. You can treat most cases at home.
In addition to upper respiratory infections like the common cold, flu, and viral skin infections such as cold sores, chickenpox, and shingles, more severe diseases caused by viruses include:
- HIV/AIDS
- Smallpox
- Ebola
- Hepatitis A (which affects your liver)
- Sexually transmitted viral infections (such as hepatitis B, genital herpes
- Human papillomavirus (HPV))
- West Nile
- Viral meningitis
Viral infections also play a role in causing cancer. It’s not a direct cause; it happens when viral infections destroy and change cells, which affect the DNA of host cells. Such mutations that occur to the DNA of host cells contribute to several different types of cancer.
How long does a viral infection last?
The length of a viral infection depends on the specific type of virus you’re fighting. Most viral infections last from several days to two weeks. Some may last longer. Some viruses are latent, meaning they can remain dormant for several years or not emerge at all. Viruses that cause latent infections include herpes, hepatitis B and C, and HIV.
A good example of a latent viral infection is varicella (chickenpox), which is caused by varicella-zoster virus. It’s a member of the herpes virus group. After getting chickenpox, the symptoms can vanish; however, the virus stays in your body as a latent infection. It may or may not appear several years later in the form of herpes zoster (shingles).
How do you stop a viral infection?
Viral infections usually clear up on their own without treatment. In some cases, you may want to treat the symptoms, which won’t cure the virus. Symptoms could be a runny nose or cough. You can take over-the-counter medicines to alleviate congestion and any aches and pains associated with a cold.
Treatment can be more challenging for some types of viral infections because viruses are small and easily reproduce inside cells. Many viruses have also become drug-resistant to antibiotics and other antiviral medications.
Your doctor may still prescribe antiviral medications, which are most effective if they’re taken early in the course of your initial viral infection. You doctor can also discuss what a viral infection is and guide you on the right course of action.
Updated:  
September 25, 2023
Reviewed By:  
Janet O’Dell, RN