Germs and microorganisms exist in every nook and cranny of the world. From the frozen glaciers of the Arctic to turbulent lava pools of active volcanos.
Remarkably adapted to every environment, germs are a carefully balanced spectrum of deadly and healthy organisms that affect our well-being, digestion, evolution, and decomposition.
But what happens when germs are outside of their preferred environments? How long do germs live on surfaces? How long are they infectious for?
Types of Germs
While there are billions of different species, germs are divided into four major categories.
- Bacteria
- Viruses
- Fungi
- Protozoa
Each class of germ has the potential to be health beneficial or detrimental; cause serious infections or be asymptomatic. Like all hazardous substances, though, the dosage will make the poison.
Because of these variances, it is not surprising that lifecycles will be different for each classification. To make a long story short, there isn’t any standard amount of time that germs live on surfaces.
Different environmental conditions will influence germ lifetime, as well as the strain of bacteria, virus or mold.
So, while it might not be possible to go over every germ, here are some of the most common ill-inducing microorganisms, and how long they can live on a surface.
How Long Do Bacteria Live on Surfaces?
Bacteria are microscopic single-celled organisms, which can be further divided into classifications based upon their shapes, genetic make-up, or by their cell wall.
Given their vast differences, bacteria have learned to survive and reproduce in a multitude of environments. There are even “friendly” bacteria, that contribute to our health, like Lactobacillus, which can be found in fermented foods, like yogurts and beer.
Streptococcus pyogenes
This gram-positive extracellular bacterium is the cause of several illnesses, such as strep throat, scarlet fever, impetigo, and toxic shock syndrome. With an incubation period of 1-3 days, patients will start experiencing symptoms rather quickly, and without antibiotics will remain communicable for 7-10 days (24 hours with antibiotics).
The bacterium can remain infectious for 3 days to 6.5 months depending on the surface.
Escherichia coli (E. coli)
The cramp inducing, low-grade fever causing, food poisoning organism is a gram-negative, rod-shaped bacterium.
Generally, contracted through contaminated foods (ground beef, unpasteurized milk, etc.), E. coli causes sickness even with little exposure (smaller dose).
Research has shown an incubation period of 2-8 days, while E. coli can remain contagious through fecal matter for up to 9 days. Regular interactions, such as kissing, handshakes, and skin contact will not transfer the bacteria.
It is recommended to surface disinfect any kitchen surfaces and items, such as cutting boards, that have come in contact with uncooked meats.
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Clean surfaces regularly, especially those coming into contact with uncooked meats.
How Long do Viruses Live on Surfaces?
Viruses are complicated when determining how long they “live” on a surface. This is because definitively, viruses are dependent on a living cell to survive and reproduce.
Nonetheless, viruses can maintain health-threatening properties outside of a host, albeit, for relatively short periods of time.
Cold and Flu Viruses
With cold and flu season slowly settling in, you might be left questioning how often should you disinfect surfaces?
The common cold has an incredibly wide array of different strains. You can expect this virus to linger on water-resistant, non-porous surfaces for up to 7 days.
Outside of a host, strains such as the Rhinovirus (the most common cold virus), lose the infectious abilities rather quickly. You can expect both cold and influenza viruses to be able to cause illness for about 24 hours out of a host. Significantly less time on tissues and hands, where they survive for only 15 minutes and 5 minutes, respectively.
Human Papillomavirus (HPV)
One of the most common types of sexually transmitted infections, it is said that almost all sexually active individuals will be exposed to this virus in their lifetimes. Vaccinations exist but are only preventative.
HPV is special as it only spreads through contact of basal cells of stratified epithelium (90% of epidermal cells).
Incubation periods are sporadic and can vary from one month to several years, with most individuals never experiencing symptoms.
Surprisingly defensive, HPV is resistant to most common disinfectants, including those used in medical environments, and survival time out of a host remains unknown.
How Long Does Mold Live on Surfaces?
Fungi are a group of eukaryotic single-celled or multinucleate organisms that thrive on the decomposition of organic material.
This category comprises of diverse organisms from molds and mildews, to yeasts and mushrooms.
So, while some can be life-threatening, there are still plenty of strains we have found uses for.
Black Mold
Scientifically known as Stachybotrys chartarum, black mold is a common household growth, found practically anywhere moisture can build-up.
Porous surfaces such as windows sills, tile grout, carpets, and drywall make perfect environments for black mold to reproduce and release its toxic spores.
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Black mold on a window sill
While moisture and oxygen are needed for black mold’s growth, removing water won't kill the fungus. Instead, in a lack of moisture, black mold will revert to a dormant state that can be reactivated when environments become favourable.
So technically, survival on surfaces are indefinite without external interference. Disinfectants are your weapons of choice when dealing with black mold in a household, as it causes respiratory issues when spores are inhaled.
Athlete’s Foot
A microscopic fungus that lives on the dead cells of hair, toenails, and skin. With at least four strains, most common infections stem from Trichophyton rubrum.
Athlete’s Foot isn’t uncommon and is often contracted from communal showers and pools through direct and indirect contact. This is because the fungi are particularly suited for warm and moist environments.
Just like black mold, you’ll want to disinfect surfaces to get rid of these contagious fungi. Standard chlorine bleach prevents athlete’s foot from spreading to other surfaces, and anti-fungal powders can be used on infected areas.
Protozoa
Historically classified as “one-celled animals”, protozoa are either free-living or parasitic microorganisms that sustain themselves on organic matter.
Almost as well adapted as bacteria, protozoans have little preference in their habitat. Existing in fresh water, brackish, saltwater, soils, mosses, and even hot springs.
The presence of moisture is all that is needed; however, several protozoan species have remarkably displayed adaptive techniques for dry climates.
Cryptosporidium
Cryptosporidium is a parasitic protozoon that makes its home in surface water reservoirs.
While symptoms vary for each host, Cryptosporidium predominantly causes diarrhea and, in some cases, respiratory cryptosporidiosis (persistent coughing). The spore phase can exist outside a host for lengthy periods, however, there aren’t any concrete studies on exact time frames.
The germ itself is usually contracted through contaminated food, water, or fecal matter exposure. Symptoms will appear anywhere between 1 to 12 days and last for two weeks. Wash hands thoroughly and disinfect surfaces with bleach to avoid the spread of contamination.
Toxoplasma Gondii
A very common type of single-celled protozoan parasite, toxoplasmosis is an infection that occurs from eating undercooked contaminated food, exposure to infected cat feces, and in some cases, transmission from mother-to-child during pregnancy.
The parasite T. gondii attaches itself to wild and domesticated cats and is excreted through their feces. It is important to wash hands after gardening; wash fruits and vegetables thoroughly; and cook lamb, pork, + and venison to their appropriate temperatures, as these mammals are likely to be infected.
Much like Cryptosporidium, T. gondii has a hardy spore phase that can remain stable for up to one year in water or moist soil.
Conclusion: How Long Do Germs Live on Surfaces?
As we stated at the beginning of the blog, there, unfortunately, isn't any standard amount of time for how long germs can survive on a surface due to the many different types of infection microbes that exist. The best way to protect yourself is to ensure surfaces are kept as clean as possible.