Viral Diseases: Symptoms, Types, Methods of Transmission

Medically Reviewed By William C. Lloyd III, MD, FACS

What are viral diseases?

Viral diseases are extremely widespread infections caused by viruses, a type of microorganism. There are many types of viruses that cause a wide variety of viral diseases. The most common type of viral disease is the common cold, which is caused by a viral infection of the upper respiratory tract (nose and throat). Other common viral diseases include:

Viral diseases are contagious and spread from person to person when a virus enters the body and begins to multiply. Common ways that viruses spread from person to person include:

  • Breathing in air-borne droplets contaminated with a virus

  • Eating food or drinking water contaminated with a virus

  • Having sexual contact with a person who is infected with a sexually transmitted virus

  • Indirect transmission from person to person by a virus host, such as a mosquito, tick, or field mouse

  • Touching surfaces or body fluids contaminated with a virus

Viral diseases result in a wide variety of symptoms that vary in character and severity depending on the type of viral infection and other factors, including the person’s age and overall health. Common symptoms of viral diseases include flu-like symptoms and malaise.

Viral diseases are not treatable with antibiotics, which can only cure bacterial diseases and infections. However, the most common viral diseases, the common cold and the flu, are self-limiting in generally healthy people. This means that the viral infection causes illness for a period of time, then it resolves and symptoms disappear as your immune system attacks the virus and your body recovers.

In some cases, viral diseases can lead to serious, possibly life-threatening complications, such as dehydration, bacterial pneumonia, and other secondary bacterial infections. People at risk for complications include those who have a chronic disease or a suppressed or compromised immune system, and the very young and very old. In addition, certain types of sexually transmitted viral infections, such as HIV/AIDS and HPV, can lead to serious complications and death. Seek prompt medical care if you think you have a viral disease, especially if you are at risk for complications, or if you believe you have been exposed to a sexually transmitted disease.

Seek immediate medical care (call 911) if you, or someone you are with, have serious symptoms of an illness or a viral disease, such as shortness of breath, chest pain, passing out (fainting), or a change in alertness or consciousness.

What are the symptoms of viral diseases?

Symptoms of viral diseases vary depending on the specific type of virus causing infection, the area of the body that is infected, the age and health history of the patient, and other factors. The symptoms of viral diseases can affect almost any area of the body or body system. Symptoms of viral diseases can include:

In infants, signs of a viral disease can also include:

  • Bulging of the soft spot on the top of the head

  • Difficulty with feeding

  • Excessive crying or fussiness

  • Excessive sleepiness

Serious symptoms that might indicate a life-threatening condition

In some cases, viral diseases can result in serious complications, such as dehydration or pneumonia. Seek immediate medical care (call 911) if you, or someone you are with, have any of the following symptoms:

  • Change in alertness or level of consciousness

  • Chest pain

  • Deep, wet chest cough that produces yellow, green or brownish phlegm

  • High fever (higher than 101 degrees Fahrenheit)

  • Lethargy or unresponsiveness

  • Seizure

  • Shortness of breath, wheezing, or difficulty breathing

  • Stiff neck

  • Yellowing of the skin and whites of the eyes (jaundice)

What causes viral diseases?

Viral infections occur when a virus enters the body and invades the inside of the body’s cells in order to reproduce. If the body’s immune system is unable to fight off the virus, it multiplies and spreads to other cells, repeating the process and leading to a widespread infection.

Types of viruses

There are many types of viruses that cause a wide variety of viral infections or viral diseases. In fact, there are more than 200 different viruses that can cause a cold or an upper respiratory infection. Other common viruses include the following:

Various ways to become infected with a virus

You can catch a virus in a variety of ways including:

  • Being bitten by an animal infected with a virus

  • Being bitten by an insect infected with a virus, such as with West Nile virus

  • Breathing in air-borne droplets contaminated with a virus

  • Eating food or drinking water contaminated with a virus

  • Having sexual contact with a person who is infected with a sexually transmitted virus

  • Sharing needles for tattooing or drug use with an infected person

  • Touching infected feces or body fluids and not washing your hands before eating or touching your mouth, eyes or nose

  • Touching surfaces contaminated with a virus

  • Transmission of a virus from an infected mother to her baby during pregnancy or delivery

What are the risk factors for contracting viral diseases?

Viral diseases can occur in any age group or population. Everybody contracts viral diseases during their life, although in some cases, the virus does not cause obvious symptoms. Risk factors for catching a viral disease or developing complications of a viral disease include:

  • Advanced age

  • Compromised immune system due to an immunodeficiency disorder, HIV/AIDS, cancer or cancer treatment, kidney disease, or other condition

  • History of chronic disease, such as asthma, COPD, diabetes, tuberculosis, or heart disease

  • Malnourishment

  • Not getting enough rest and having high levels of stress

  • Not washing your hands frequently, especially before eating or after using the restroom, or after touching common surfaces

  • Sharing needles to inject drugs or for tattooing

  • Unprotected sex including vaginal, oral and anal sex with a partner who has had one or more other sexual partners

  • Young age including infancy and elementary-school-age children

Reducing your risk of viral diseases

You can lower your risk of catching or spreading a viral disease by:

  • Abstaining from sexual activity, or only engaging in sexual activities within a mutually monogamous relationship in which neither partner is infected with a sexually transmitted disease

  • Avoiding contact of your hands with your eyes, nose and mouth, which can transmit a virus into the body

  • Avoiding contact with a person who has a viral disease

  • Covering your mouth and nose with your elbow (not your hand) or a tissue when sneezing or coughing

  • Eating a well-balanced diet that includes sufficient amounts of fruits and vegetables

  • Sufficient rest

  • Using a new condom for each sex act

  • Using a sterile, unused needle for each act of tattooing or injectable drug use

  • Using appropriate antibacterial cleaners to clean your hands and surfaces

  • Vaccination as recommended by your health care provider for viral diseases, such as chickenpox, shingles, influenza, HPV, hepatitis B, hepatitis A, measles, and mumps

  • Washing your hands with soap and water for at least 15 seconds after contact with a person who has a viral disease, before eating, or after using the restroom or touching feces, body fluids, surfaces, or foods that are potentially contaminated with viruses

How are viral diseases treated?

Treatment of viral infections varies depending on the specific virus and other factors. General treatment measures are aimed at relieving your symptoms so that you can get the rest you need to keep up your strength and recover without developing complications.

General treatments for viral infections include:

  • Acetaminophen (Tylenol) or ibuprofen (Motrin, Advil) for fever, body aches, and pain

  • Drinking extra fluids

  • Getting extra rest and sleep

  • Maintaining good nutrition

Depending on the type of viral infection and the presence of complications, a wide variety of other treatments may be needed. For example, a human papillomavirus (HPV) infection that leads to cervical dysplasia can be treated by surgical removal of the abnormal cells on a woman’s cervix.   

In general, it is recommended that children younger than age six not use cold or cough medications because of the risk for serious side effects. In addition, people with a viral disease should not use aspirin or products that contain aspirin because of the risk of developing a rare but life-threatening condition called Reye syndrome. Reye syndrome has been linked to taking aspirin during a viral illness, such as a cold or the flu.

Prescription medications used to treat viral diseases

In some cases, certain medications may be prescribed to treat viral diseases:

  • Antiretroviral medications, which can help people with HIV/AIDS lead longer lives. Antiretroviral medications hinder the ability of HIV to reproduce, which slows the spread of HIV in the body.

  • Antiviral drugs, which minimize the severity and length of some viral infections, such as the flu and shingles, especially in people who are at a high risk for serious complications. For example, the drugs oseltamivir (brand name Tamiflu) and zanamivir (brand name Relenza) may be prescribed for some cases of flu. These drugs are not appropriate for all people with the flu.

Antibiotics, which are not prescribed for viral diseases because they are ineffective in the treatment of viral infections, may be prescribed if a person with a viral disease develops a secondary bacterial infection, such as bacterial pneumonia, bacterial bronchitis, or encephalitis.

Complementary treatments

Complementary and traditional treatments will not cure a viral disease but may help to increase comfort, promote rest, and minimize symptoms of viral diseases. Some possible treatments include:

  • Chicken soup to help break up congestion and provide easy-to-digest nutrients and extra fluids to help keep up strength

  • Supplements or products that contain vitamin C, echinacea, or zinc

  • Using a vaporizer

  • Using mentholated ointments on the chest

What are the possible complications of viral diseases?

In some people, viral diseases can break down the body’s defenses and lead to more serious infections and life-threatening complications. Therefore, it is important to visit your health care provider when you have symptoms of a viral infection. Once the underlying infection has been determined, following the treatment plan outlined by your health care provider can help reduce any potential complications including:

Was this helpful?
2637
  1. Chickenpox. Centers for Disease Control and Prevention. http://www.cdc.gov/vaccines/vpd-vac/varicella/in-short-adult.htm
  2. Genital HPV Infection. Centers for Disease Control and Prevention. http://www.cdc.gov/std/HPV/STDFact-HPV.htm
  3. Respiratory Syncytial Virus. PubMed Health. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002531/
  4. Viral Gastroenteritis. Centers for Disease Control and Prevention. http://www.cdc.gov/ncidod/dvrd/revb/gastro/faq.htm
  5. Common Cold. National Institute of Allergy and Infectious Diseases. http://www.niaid.nih.gov/topics/commonCold/Pages/cause.aspx
Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Nov 20
View All Infectious Diseases Articles
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.