Liam is a long-time writer who enjoys learning about and sharing information about health, space, and material sciences.
Note to Reader
The SARS-CoV2 virus (Severe Acute Respiratory Syndrome - Corona Virus 2) is still relatively new. For that reason research is ongoing regarding it's ability to remain viable on surfaces, in the air, and in people who have been infected. As of October 12, 2020, Australia's National Science Agency, CSIRO's disease preparedness centre found that SARS-CoV2 could live, in the dark, at 68°F, on smooth surfaces such as glass, for up to 28 days.
The Ebola virus, also called the Ebola Virus Disease or EVD was largely a short-lived virus. The reason it did not infect and kill more people is that it was so deadly that those infected were rarely able to move around and infect others.
The "Life" Expectancy of a Virus Varies
First, there is still some disagreement as to whether a virus is actually alive. This is primarily due to the fact that a virus does not have mitochondria, the mechanism that powers a cell. For this reason "viability" is often the word used to describe the survival rate (life) of a virus as opposed to "life*."
Due to a number of factors, such as internal structure, outer coating, and environment conditions, viruses display a huge range of time in how long they can persist in an infectious state. Some viruses require water to remain viable, others require a particular temperature range, others still do better out of direct light.
In almost all cases, viruses can be killed by tearing apart their structure. Substances that can have this effect on a virus include soap, bleach, and the UV rays from sunlight.
* Note that scientists are somewhat divided on whether or not a virus is actually a living thing. Some claim that the fact that it contains RNA means it is living. Others claim that since it lacks mitochondria (the powerhouse of living cells) it is a non-living particle similar to a crystal.
How Long Does a Virus "Live" Outside a Host?
Some viruses can "live*" undisturbed for years. Others are so fragile that they can only withstand "external" conditions for mere minutes if not seconds. This article will name a number of viruses and define their "life expectancy" outside a host cell.
Imagine that this "outside a host cell" is a doorknob, phone, computer keyboard, or play-yard.
For the sake of consistency, a surface on which a virus can "live" will have a specific definition. The surface most "friendly" to viruses is typically characterized as one that it is not in direct sunlight, is not exposed to cleaning chemicals, and is in a temperature controlled environment; one that is neither too hot or too cold.
Another way to put this is an environment that most humans would find comfortable.
Additionally, a smooth dry surface is more hostile to viruses (and bacteria) than a surface such as cloth or carpet.
Zoonosis (Zoo-ah-no-sis): A process where infectious diseases are passed between species. This would include the transmission of swine flu between pigs and humans or the transmission of EVD between bats and humans.
Hemorrhagic means, "bleeding" or "abnormal flow of blood."
Ebola attacks endothelial cells in blood vessels. These are the cells that line blood vessels and arteries and prevent fluids within those vessels from leaking out. Because EVD attacks and weakens these cells, smaller vessels such as capillaries begin to leak into surrounding tissue. Larger arteries have a muscular outer wall which prevents leaks, but because the virus attacks their lining as well, those muscle linings weaken and atrophy.
One symptom of EVD is pink or red in the whites of the eyes.
Fil (Filo): is Latin for thread or filament.
Virus: Latin for poison.
Thus, any virus with a threadlike structure, such as Marburg or Ebola is a virus in the Filoviridae family.
Ebola (EVD*) was discovered in Zaire in 1975. It is thought to be transmitted through blood and other bodily fluids such as saliva, urine, feces, blood, breast milk, semen, and vomit. Transference of this virus occurs when these liquids make contact with the other person’s mouth, eyes, or openings. This virus can also be transferred to open wounds such as cuts, burns, and abrasions.
The virus can also be transmitted to humans via the above described pathways with the fluids from infected mammals. Bats are the prime animal suspect at this time, however this has not been confirmed.
Ebola cannot be spread via insects, air, food, or a water pathway. In other words, the virus appears to spread via animal to human, human to human, or animal to animal contact when bodily fluids are exchanged.
Symptoms include sudden onset fever, chills, myalgia (muscle pain), and malaise (general discomfort). These general symptoms are typically displayed eight to ten days after exposure, however, it is possible for this virus to remain inactive for up to twenty-one days after exposure.
Five days after displaying the above symptoms, the victim may then display stomach pain, watery diarrhea, nausea, vomiting, and general abdominal pain. Other symptoms might include chest pain, headache, shortness of breath, and or confusion.
A person recovering from this virus carries Ebola antibodies that are effective against this virus for up to ten years.
Once someone recovers from Ebola, they are no longer infectious. Note however, that active Ebola virus has been found in semen for up to 3 months after recovery.
Ebolavirus can survive, out in the open, for two to three hours on hard dry surfaces. It can survive for over twenty-four hours (two or three days) in the presence of water such as a puddle.
The "Dog Rumor"
Recently, a Spanish mixed breed dog named Excalibur was put down by the Spanish state because it's owner, a nurse, contracted EVD. This was done on the theory (unproved so far) that canines can host the virus, with no symptoms, yet pass the disease on to humans.
The Centers for Disease Control categorically state that there is no current evidence that dogs or cats can transmit the disease to humans. However, no definitive test has been conducted to verify or disprove that EVD can be passed from pets to people.
*Ebola Virus Disease
This virus has the Latin name Variola major with a secondary version called Variola minor. Variola is Latin for "spotted." It is believed that this virus is 12,000 years old.
Smallpox is estimated to have been responsible for three hundred (300,000,000) to five hundred (500,000,000) million deaths worldwide in the last century alone.
The smallpox virus, at room temperature, in an undisturbed environment, can remain viable for years if not decades. Fortunately, smallpox has been eradicated.
Hepatitis A , B & C
Hepatitis A & B are viruses that typically attack the liver. Roughly ten million people a year are infected with either of these two viruses.
Symptoms become noticeable in two to six weeks. Almost all who contract one of these two viruses overcome the infection and retain lifelong immunity against them. Some contracting Hepatitis B will later suffer from cirrhosis of the liver or possibly even liver cancer.
Hepatitis C is an even more serious version of the virus with approximately (300,000,000) three hundred million infected worldwide. Hepatitis C can spontaneously "clear" meaning some people's immune systems can kill it off, However, most who have contracted the virus will suffer liver problems including cirrhosis and cancer.
The Hepatitis A virus can remain viable on surfaces (see above) for up to a month. The Hepatitis B viruses can live, undisturbed on surfaces outside a host cell for up to a week. Hepatitis A is commonly contracted via the feces/oral route or through food, though not commonly sexually. Hepatitis B can also be contracted as with Hepatitis A and also sexually.
Hepatitis C requires "blood-to-blood" contact and therefore cannot survive outside a host cell. It is not commonly contracted via intimate bodily contact.
All forms of Hepatitis co-opt liver cells to reproduce the viral components.
Human Immunodeficiency Virus
This is what is called a "retrovirus." Such a virus can incorporate it's RNA into the host cell's DNA and thereby "hide" from detection. Also, such viruses replicate along with cells as they divide. This way the virus can hide indefinitely within a collection of host cells. Worse, these cells are often the very cells used in immune response. Additionally, HIV can hide within bone marrow stem cells; the same cells that eventually become blood cells.
HIV can typically survive outside a host cell undisturbed for no more than a few hours.
Rhinovirus (common cold)
The rhino-virus (rhino meaning "nose" in Latin) is one of the smallest of all viruses. it is responsible for over half of all cold symptoms.
Rhino-viruses typically attack the sinus tract. Symptoms typically last about a week.
These viruses are often transferred from human to human via contact with the skin. Such contact may include kissing, handshakes, and other forms of non-intimate contact. These viruses can also be deposited on hard surfaces by one human, picked up or touched by another human, and then transferred to the nose or mouth.
A rhino-virus can live undisturbed outside a host cell for up to a day.
This is the virus responsible for Spanish Flu, Avian Flu, and Swine Flu. An infection is often mild lasting no more than a week, but for some it can be quite deadly. The Spanish Flu killed upwards of five hundred million people. To date, Swine Flu has killed six hundred people in the United States.
Influenza typically invades the lungs.
It is thought that influenza viruses can last outside a host cell undisturbed for up to two days.
Virus Viability Depends on the Surface
Recent research has shown that viruses, the flu virus in particular, "live" longer on stainless steel, plastic and other hard, impermeable surfaces than on softer fabric surfaces. There is still no definitive timetable for viability because so many factors are involved including exposure to light, humidity, and temperature.
Examples of hard surfaces include counter-tops, doorknobs, desk-tops and the like.
Soft surfaces would include fabric covered furniture and clothing.
Regardless the flu virus is far more hardy than a cold virus.
How to Kill Viruses on Surfaces
Viruses are susceptible to a wide variety of conditions and chemicals. In this example I will assume the virus to be eradicated from a surface is the influenza virus.
The flu virus is killed by heat (167-212°F [75-100°C]). It can also be killed with chlorine (household bleach), hydrogen peroxide, soap (dish-washing and hand), iodine based cleaners, and alcohols. The flu virus can also be killed by the ultra-violet light in sunlight.
- Hand wipes or gels with alcohol in them
- Rubbing alcohol
- Household hydrogen peroxide (2% concentration)
- Diluted chlorine bleach (4 Tablespoons per gallon of water)
- Bar soap or pump liquid soap
- Dish-washing liquids
- Dishwasher soaps
- Direct sunlight (or ultraviolet light source)
- Automatic Dishwasher (with heating element)
- Oven temperatures (baking)
- Boiling water
The idea of this particular article is provide the reader with information on just how viruses manage to infect people. If a virus can lie undisturbed on any surface, "alive" and active, it is very easy to touch that surface, then your face or mouth, and acquire an infection that way.
Direct human contact is not the only way to pick up a viral infection.
Chala Dandessa on December 24, 2017:
Thank u that is good!
J bunch on September 28, 2014:
Great article :) do you know why the cdc says that hepatitis A can live for months, your article says a week? thanks
ImanAlipk on July 04, 2010:
Hepatitis B and C are so dangerous.Thanx for the gud information.
LiamBean (author) from Los Angeles, Calilfornia on June 18, 2010:
Thanks Vicki. I was really astonished at the smallpox virus, but I guess it makes sense. It was pretty hard to eradicate.
Vicki on June 18, 2010:
Thank you for the helpful information on Viruses. I currently handle the Health & Safety for a medical clinic and questions of this nature are often asked. Now I will pass on your article!
LiamBean (author) from Los Angeles, Calilfornia on March 08, 2010:
Gypsy Willow: Remember that sunlight, detergent, and bleach all shred viral structures. Sunlight is cheap and plentiful.
Gypsy Willow from Lake Tahoe Nevada USA , Wales UK and Taupo New Zealand on March 08, 2010:
Thanks for this hub. I shall probably spend the day house cleaning now. Essential information, thanks
LiamBean (author) from Los Angeles, Calilfornia on February 10, 2010:
Detoxguide: Thanks for reading. I was astonished when I looked up SmallPox. Good thing it's gone!
Detoxguide from Beverly Hills on February 10, 2010:
This is very interesting. Viruses are so small yet so deadly.
commoncent$ on December 18, 2009:
LiamBean (author) from Los Angeles, Calilfornia on November 10, 2009:
Thank you dnrkrishnan25.
dnrkrishnan25 on November 10, 2009:
LiamBean (author) from Los Angeles, Calilfornia on October 14, 2009:
Thanks Mmrjmr1 and Shalini. Thankfully the only known virus to last for years is smallpox. It is now relegated to the lab and no longer in the general world population.
Shalini Kagal from India on October 08, 2009:
Very interesting - and comprehensive! To think that some of them can stay alive for years is scary to say the least!
Hmrjmr1 from Georgia, USA on October 07, 2009:
Good Info Thanks