A viral infection is the multiplication of a harmful virus inside your body. Viruses cannot reproduce without the help of a host. Viruses infect the host by inserting their genetic material into cells and hijacking the cell’s internal machinery to produce more virus particles.
With an active viral infection, a virus copies itself and ruptures (kills) the host cell to release the newly formed virus particles. In other cases, virus particles germinate from the host cell over time before killing the host cell. Either way, new virus particles are released to infect other cells. Symptoms of the viral disease occur due to cell damage, tissue destruction, and the associated immune response.
Some viruses—such as those that cause chickenpox and herpes—may remain inactive or “latent” after the initial infection. For example, you may have a cold sore that erupts and then heals.
The herpes virus remains dormant in your cells. Later, a stimulus, such as stress, sunlight, or something else, may reactivate the virus and lead to new symptoms. The virus makes more copies of itself, releasing new virus particles and killing more host cells.
Viruses are tiny particles of genetic material (DNA or RNA) surrounded by a protein coat. Some viruses also have a lipid coating. They cannot reproduce on their own. Viruses depend on the organisms they infect (the host) for survival.
Viruses get a bad rap but perform many essential functions for humans, plants, animals, and the environment. For example, some viruses protect the host against other infections. Viruses also participate in the evolution process by transferring genes among different species. In biomedical research, scientists use viruses to introduce new genes into cells.
When most people hear the word “virus,” they think of pathogenic (disease-causing) viruses such as the common cold, influenza, chicken pox, human immunodeficiency virus (HIV), SARS-CoV-2, etc. Viruses can affect many body areas, including the reproductive, respiratory, and digestive systems. They can also affect the liver, brain, and skin. Research shows that viruses also play a role in many cancers.
Microbiologists still disagree. Those who say viruses are alive offer these reasons:
Reasons why some say viruses are not alive:
Contagiousness refers to the ability of a virus to spread from one person (or host) to another. Viral infections are contagious for different periods, depending on the virus.
The incubation period refers to the time between exposure to the virus (or other pathogen) and the onset of symptoms. The contagious period of a virus is not necessarily the same as the standard period.
Viruses and bacteria are two types of potentially pathogenic (disease-causing) particles. Viruses are much smaller than bacteria and cannot reproduce without the help of a host.
Bacteria can reproduce on their own. Symptoms of viral and bacterial diseases are sometimes similar. A doctor can determine the root cause of a disease based on the patient’s symptoms and other factors. Laboratory tests help clarify whether an illness is due to a virus, bacteria, or other infectious agent or disease process.
Viruses can be transmitted in different ways. Some viruses can spread through touch, saliva, or even air. Other viruses can be transmitted through sexual contact or shared contaminated needles.
Insects, including ticks and mosquitoes, can act as “carriers” and transmit the virus from one host to another. Contaminated food and water are other potential sources of viral infection.
Respiratory viral infections affect the lungs, nose, and throat. These viruses are primarily spread through inhalation of droplets containing virus particles. Examples are:
Frequent hand washing, covering the nose and mouth when coughing or sneezing, and avoiding contact with infected people can all reduce the spread of respiratory infections. Disinfecting hard surfaces and not touching the eyes, nose, and mouth can also help reduce transmission.
Wearing a mask when going out and staying away from groups of people indoors (social distancing – staying at least 6 feet away from others) may reduce the chance of contracting viral infections such as the flu and Covid-19.
Viral skin infections can range from mild to severe and often cause a rash. Examples of viral skin infections include:
The best way to prevent viral skin infections is to avoid skin-to-skin contact (especially areas that have rashes or sores) with an infected person. Some viral skin infections, such as varicella-zoster virus, are also transmitted through the air. Public showers, swimming pools, and contaminated towels can also potentially contain certain viruses.
Viruses are one of the most common causes of food poisoning. Symptoms of these infections vary depending on the virus involved.
It is unpleasant to think about, but foodborne viral illnesses are transmitted through fecal-oral routes. This means that a person gets the virus by eating virus particles that have been shed through the feces of an infected person.
A person with this type of virus who does not wash his hands after using the toilet can transmit the virus to others by shaking hands, preparing food, or touching hard surfaces. Contaminated water is another potential source of infection.
Sexually transmitted viral infections are spread through contact with body fluids. Some sexually transmitted infections can also be transmitted through blood (blood-borne).
Human papillomavirus (HPV) is the most common sexually transmitted infection in the United States. There are different types of HPV. Some cause genital warts, while others increase the risk of cervical cancer. Vaccination can protect against cancer-causing strains of HPV.
Hepatitis B is a virus that causes inflammation in the liver. It is transmitted through infected blood and body fluids. Some people with the virus have no symptoms, while others feel like they have the flu. The Hepatitis B vaccine is more than 90% effective in preventing infection.
Genital herpes is a common sexually transmitted infection caused by the herpes simplex virus-2 (HSV-2). Herpes simplex virus 1 (HSV-1), responsible for herpes, can also sometimes cause genital herpes.
There is no cure for genital herpes. Painful sores often recur during outbreaks. Antiviral drugs can reduce the number and length of outbreaks.
Human immunodeficiency virus (HIV) is a virus that affects certain types of T cells of the immune system. The progression of the infection reduces the body’s ability to fight disease and infection, leading to acquired immunodeficiency syndrome (AIDS). HIV is transmitted through contact with an infected person’s blood or body fluids.
People can reduce their risk of sexually transmitted infections by abstaining from sex or only having sex in a monogamous relationship with someone who does not have a sexually transmitted infection. Condom use reduces the risk of sexually transmitted infections but does not eliminate them.
Minimizing the number of sexual partners and avoiding intravenous drug use are other ways to reduce the risk of sexually transmitted and blood-borne viral infections.
Other viral infections include Epstein-Barr virus (EBV), a type of herpes virus; West Nile virus (WNV), a virus that is mainly transmitted by infected mosquitoes; and viral meningitis, an inflammation of the inner lining of the brain and spinal cord that causes headaches, fever, neck stiffness, and other viral infections. Symptoms become.
Many viral infections resolve on their own without treatment. In other cases, treatment for viral infections focuses on relieving symptoms, not fighting the virus. For example, cold medicine helps relieve the pain and congestion of a cold but does not directly affect the cold virus.
Some drugs directly affect viruses. These are called antiviral drugs.
Antiviral drugs are most effective when taken early during a primary viral infection or recurrent outbreak. Antiviral drugs may treat chickenpox, shingles, herpes simplex virus-1 (HSV-1), herpes simplex virus-2 (HSV-2), HIV, hepatitis B, hepatitis C, and the flu.
Vaccines can reduce the risk of some viral diseases. Vaccines to help protect against influenza, hepatitis A, hepatitis B, chicken pox, herpes zoster (shingles), cancer-causing strains of human papillomavirus (HPV), measles/mumps/rubella (MMR), polio, rabies, rotavirus, and other viruses
Vaccines vary in effectiveness and the number of doses required to provide protection. Some vaccines require booster shots to maintain immunity.
Viral infections occur due to contamination with viruses. Millions of viruses may exist, but researchers have identified only about 5,000 types.
Some viruses, such as human papillomavirus (HPV) and Epstein-Barr virus (EBV), can cause cancer by forcing cells to multiply excessively. A virus can also target specific age groups, such as infants or young children.
Antiviral medications can help relieve the symptoms of some viruses.
They can prevent the reproduction of the virus or strengthen the host’s immune system and neutralize the effects of the virus.
Antibiotics are ineffective against viruses and do not stop the virus, and their use increases the risk of antibiotic resistance.
Dr. Majid Zohrabi started treating his patients in Dubai in 2022 and continues his activities in private medical centers in the UAE.