Most Common Viruses in Humans: Viruses are infection-causing tiny agents, made up of genetic material like DNA and RNA, covered in a protein coating. Viruses are submicroscopic.
Viruses invade living cells and use cell components to help themselves to replicate. During this, the host cells infected by viruses are killed or damaged.
Viruses are found all over the world. Over 9,000 types of viruses have been described in detail. Viruses can infect humans, animals, and plants, also viruses can infect microorganisms like bacteria.
Any illness or health condition caused by a virus is called a viral disease. Here in this post, we will take a look at some of the most common viruses in humans.
Are Viruses Always Contagious?
All diseases spread by viruses are not contagious, which means they do not always spread from one person to another person. But several of these diseases are contagious. HIV, common cold, flu, and herpes are examples of contagious viral diseases.
Other viral disease types can spread in other ways, like infected insect’s bite.
What Are the Most Common Viruses Found In Humans?
Here are 5 viral diseases that are most common in humans.
Viral Respiratory Diseases
Respiratory viruses are the most common viruses in humans. Viral respiratory diseases are contagious and usually affect the upper or lower respiratory tract.
Respiratory viruses are the most common cause of human disease and have a notable impact on disease and death worldwide. 
The most common respiratory viruses on all continents are respiratory virus, parainfluenza virus, influenza virus, adenovirus, metapneumovirus, rhinovirus, bocavirus, and coronavirus.
Respiratory viral infection symptoms include:
- A cough, with mucus
- Running or stuffy nose
- Soreness in throat
- Aches in muscles
Coughing or sneezing droplets spread respiratory viruses. If a person with a viral infection coughs or sneeze near you and you inhale these drops, you can catch the illness.
Also, contaminated objects like door handles, table surfaces, and personal items spread these viruses. If you touch any of these objects and then touch your nose or eyes, you may get this respiratory viral disease. 
Viral respiratory illnesses usually go away on their own. However, over-the-counter medicines, including nasal decongestants, cough suppressants, and painkillers, may lower symptoms.
Besides, an antiviral drug called Tamiflu is prescribed sometimes when a person is in the early stages of the flu.
It is best to follow good hygiene to become safe from viral diseases. When you cough or sneeze cover your mouth, often wash hands, and limit contact with people who have respiratory infection symptoms.
Viral Gastrointestinal Diseases
Norovirus, Rotavirus, Adenovirus, and other viruses cause gastrointestinal diseases that affect the digestive tract. The viruses are contagious and they usually cause a health condition called gastroenteritis this is also known as gastritis.
Gastrointestinal viral diseases cause inflammation of the stomach, small intestine, and colon. Viral gastroenteritis infection caused vomiting or diarrhea.
Symptoms of Viral Gastrointestinal Infections
- Watery diarrhea
- Cramps or pain in the abdomen
- Vomiting or nausea
- Sometimes headaches or muscle aches
Viral gastrointestinal is a contagious disease that is spread through feces, shaking hands with people who are sick and have a virus on their hands, touching items contaminated with the virus, and consuming contaminated food or water.
The infection can also be transmitted by particles that are sprayed when people vomit.
Most cases of viral gastrointestinal spread come from people having symptoms. Infection can pass on from people who don’t have symptoms, especially the first 48 hours after recovery.
Patients with gastroenteritis in most cases recover on their own without medicines. The disease can be treated by taking plenty of fluids to fill full those that are lost due to vomiting and diarrhea.
Over-the-counter medicines like Imodium, Pepto-Bismol, and Kaopectate in some cases can aid to alleviate symptoms. 
Viral diseases of the digestive tract can be prevented by frequent hand washing, particularly after the washroom. Cleaning surfaces with contamination and not sharing personal belongings or utensils can also help.
Also, a rotavirus vaccine is there that is recommended in the vaccination schedule for children.
Hepatic Viral Disease
Hepatic viruses are also the most common viruses in humans. Viral hepatitis is a disease due to which inflammation and damage to the liver occur. When body tissues are infected or injured it causes inflammation. Body organs can damage due to this inflammation. 
Five major hepatitis viruses are there, referred to as types A, B, C, D, and E. It is worth bearing in mind that illnesses caused by other viruses, like yellow fever virus and cytomegalovirus, can also affect the liver.
Acute and chronic or long-lasting illnesses can occur due to B, C, and D hepatitis viruses. 
How is viral hepatitis transmitted?
B and C hepatitis can pass on from one person to another through body fluids. The viruses can also spread by object sharing like razors and needles that have come in contact with blood. Transmission of hepatitis B can also occur through sexual intercourse.
People become infected with hepatitis A and E by eating food or drinking water contaminated with the feces of a person infected with hepatitis viruses. Hepatitis D can only develop if the hepatitis B virus is already present in a person.
Hepatitis B, C, and D treatment focus on the treatment of symptoms. Antiviral drugs in some cases may be prescribed by your doctor. Medicines such as tenofovir, adefovir, telbivudine can aid in fighting the virus and slow down the virus’s capability to damage the liver.
Hepatitis A and E treatment include supportive measures like adequate rest, fluid intake, and alcohol avoidance.
Vaccines are present for both hepatitis A and B. Vaccine for hepatitis E is also there, but in the US, presently there is no FDA-approved hepatitis E vaccine available. 
You can also take prevention against hepatitis by not sharing objects like razors and needles. Safe sex practice, avoiding food and drinks that may have feces contamination are also good preventive steps.
Exanthematous viral disease
A viral infection is the most common cause of exanthematous viral disease the infection causes skin changes either directly or through the immune system reaction. 
The exanthematous virus causes rashes on the skin. Chickenpox, measles, German measles, and other viral infections that cause mumps and skin rashes are included in exanthematous viral infections. Many of them also cause other symptoms. The measles virus of this category is highly contagious.
How Exanthematous viral disease spread?
Several exanthematous viruses spread from droplets by coughing or sneezing of a person who is suffering from the virus. Transmission of other viral exanthematous illnesses like smallpox and chickenpox occurs by contact with fluids on damaged skin.
People get shingles only if at some point they had chickenpox. It is a reactivation of the smallpox virus that is dormant in a person’s cells. Mosquito bite spreads the Chikungunya virus and it is not passed on from one person to another person.
Exanthematous viral diseases treatment focuses on symptoms control. No treatment is required for mild symptoms because the rash and disease usually last only a few days and then disappear. Antiviral medicines like acetaminophen can help lower pain and fever.
For shingles and chickenpox, Acyclovir an antiviral drug is used. Adequate sleep and drinking a lot of fluids also help.
Exanthematous Viral Diseases Prevention
Vaccination can prevent measles, smallpox, chickenpox, rubella, and shingles. MMR vaccine is effective against measles, mumps, and rubella. By protecting from mosquito bites Chikungunya infection risk can be reduced.
Hemorrhagic viral diseases
Hemorrhagic viral diseases are severe health conditions occurred due to four virus families- Arenaviridae, Bunyaviridae, Filoviridae, and Flaviviridae. These illnesses include Ebola, Marburg hemorrhagic fever, dengue fever, yellow fever, and Crimean-Congo hemorrhagic fever.
A big number of symptoms are associated with these viruses including coagulation disorders, hemodynamic instability, mood swings, effects on the cardiovascular system and other organs, effect controlling ability of the body, and in severe conditions death can occur. 
hemorrhagic viral diseases symptoms include, underskin bleeding, internal organ bleeding, weakness, high fever, aches in the body, under skin bleeding, vomiting, diarrhea, etc.
Dengue fever and yellow fever hemorrhagic viral illnesses spread through an infected insect bite.
Other illnesses, like Ebola, infect people when they come in contact with the blood or other body fluids of the virus carrier. Lassa fever is spread by inhaling or ingesting dry feces or urine from a virus-infected rodent.
Although a specific treatment for hemorrhagic viral disease is not available. In preventing some complications and shortening infection course antiviral medicines ribavirin (Rebetol, Virazole) can be used. Developments of other drugs are on the way.
Stay hydrated is necessary in case you have a hemorrhagic disorder. Intravenous (IV) fluids may need in some people to maintain electrolyte balance. To maintain electrolyte balance supportive care is required.
Hemorrhagic Viral Diseases Preventions
Researchers are currently developing vaccines against hemorrhagic viruses. Yellow fever vaccine is available to people traveling to areas where this fever is common.
In case you are living or work in an area where hemorrhagic viruses commonly occur, you can reduce the risk of getting these viruses by taking the following steps:
- Wear suitable protective equipment, like gloves, goggles, or a face shield, when working near infected persons.
- Avoid biting insects, particularly ticks and mosquitoes, by putting on protective clothes or by insect repellent use.
- Protect yourself from rodent infections by covering food; frequently remove the garbage, and be sure that windows and doors are tightly closed.
There are thousands of viruses worldwide that infect humans, animals, and plants, even bacteria can be infected by viruses. The most common viruses in humans are respiratory viruses, gastrointestinal, hepatic viruses that cause several types of illnesses in humans.
Some of these illnesses are mild like stomach flu and run away within a few days on their own, but some are dangerous. Unlike bacterial diseases, antibiotics are not effective against viral diseases. Rather, symptoms treatment often focuses on controlling them and supports the immune system with supportive measures like a lot of fluids and rest.