A viral disease is defined as any illness caused by a virus. Viruses are microscopic germs that infect normal cells found within plants, animals, and humans. They are the culprit for many familiar illnesses, such as the common cold and flu. They are also the culprit for more serious illnesses, such as SARS (severe acute respiratory syndrome), measles, hepatitis, herpes, and viral meningitis.
Different viruses target different cells within the body. As a result, the symptoms of viral diseases are numerous and varied. For example, the coronavirus responsible for SARS targets the epithelial cells found within the respiratory tract. Subsequently, the symptoms of SARS predominately involve the respiratory system. Symptoms include cough, shortness of breath, and lung damage. This contrasts with the hepatitis C virus, which targets the liver cells. The symptoms of hepatitis C predominately involve the liver and digestive system. Symptoms include jaundice, abdominal pain, nausea, and vomiting.
The symptoms of viral diseases are too numerous and varied to list out in their entirety. However, there are a handful of symptoms that are shared by most viral diseases. The symptoms listed below are indicative of a viral infection:
Viral diseases are caused by infectious pathogens called viruses. Viruses can be transmitted directly from an animal to a person (i.e., from a mosquito bite) or from one person to another person. They can also be transmitted indirectly from a contaminated object to a person. Viruses enter a person’s body through the nose, mouth, eyes, genitals, or breaks in the skin.
Below is a list of viral diseases and their causative virus:
| Viral Disease | Virus |
| Influenza | Influenza virus |
| Common cold | Rhinovirus |
| Respiratory syncytial virus infection | Respiratory syncytial virus (RSV) |
| Parainfluenza virus infection | Parainfluenza virus |
| Severe acute respiratory syndrome (SARS) | Coronavirus (SARS-CoV) |
| Norovirus infection | Norovirus |
| Rotavirus infection | Rotavirus |
| Astrovirus infection | Astrovirus |
| Measles | Morbillivirus |
| Rubella | Rubella virus |
| Chickenpox | Varicella-zoster virus (VZV) |
| Roseola | Human herpesvirus 6 |
| Smallpox | Variola virus |
| Fifth disease | Parvovirus B19 |
| Chikungunya virus infection | Chikungunya virus |
| Hepatitis A | Hepatitis A virus (HAV) |
| Hepatitis B | Hepatitis B virus (HBV) |
| Hepatitis C | Hepatitis C virus (HCV) |
| Hepatitis D | Hepatitis D virus (HDV) |
| Hepatitis E | Hepatitis E virus (HEV) |
| Oral herpes | Herpes simplex virus type 1 (HSV-1) |
| Genital herpes | Herpes simplex virus type 2 (HSV-2) |
| Molluscum contagiosum | Poxvirus |
| Polio | Poliovirus |
| Viral meningitis | Non-polio enterovirus |
| Rabies | Rabies lyssavirus |
Viruses can infect anyone regardless of their age, ethnicity, race, or culture. However, there are certain activities that make one more prone to catching a virus. These include:
There are also certain factors that increase one’s chances of suffering a severe viral infection. These include the following:
The following tests are used to diagnose a viral disease:
This test measures the levels of immunoglobulins, or antibodies, found within the blood. Elevated levels are a sign that your body is creating antibodies to fight off a viral infection.
PCR tests are used to check for viruses found within a test sample. Test samples can consist of a patient’s blood, saliva, mucus, urine, stool, or tissue. During a PCR test, the genetic material found within the test sample is replicated and amplified. A machine then checks the genetic information against a library of known viruses.
Rapid tests can diagnose certain viral diseases, such as flu, strep throat, malaria, HIV, and COVID-19, within twenty minutes or less. A rapid test will return a positive diagnosis if unique protein fragments, or biomarkers, for a virus are found in the test sample.
A respiratory pathogens panel is used to check for bacteria and viruses that commonly infect the respiratory system. During the test, a nasopharyngeal swab is taken from the patient. A machine then studies the genetic material found on the swab. The machine can recognize the genetic code for various viruses that infect the respiratory system (i.e., influenza virus, RSV, rhinovirus, adenovirus, coronavirus, and enterovirus).
Viruses cannot be killed by antibiotics. For most viral diseases, treatment consists of easing the symptoms of the viral disease while waiting for the body’s immune system to fight off the virus. The following treatments can be used for life-threating situations or for those who are immunocompromised:
Antiviral medicines are available to treat several viral diseases, such as the flu, Ebola, hepatitis B, hepatitis C, herpes, HIV, and COVID-19. Antiviral medicines cannot get rid of the virus completely. The medicines work to lower the viral load by preventing the virus from binding to and invading healthy cells.
Convalescent plasma is donated by a person who has recovered from a specific viral disease. Their plasma contains the antibodies needed to fight off the virus. Convalescent plasma is given to a patient through a blood transfusion. The patient will then have the necessary antibodies to fight off the viral infection themselves.
The spread of viral diseases can be prevented by doing the following:
One of the best ways to prevent many viral diseases is to stay up to date with vaccinations. Vaccinations are available for influenza, rotavirus, measles, rubella, chickenpox, hepatitis A, hepatitis B, polio, and rabies.