Did Bats Cause Coronavirus?

Did the Chinese Coronavirus COVID-19 Come from Bats?

Author: David Seerveld

With the coronavirus, now named COVID-19, on the rise, most people want to know where it came from and what they can do to prevent contracting it or getting a similar disease in the future. Bats are one of the most likely suspects as a vector in the origin of coronavirus.

Coronavirus Is Almost Certainly from Bats

So far, it seems almost certain that the coronavirus came from bats. A team at the Wuhan Institute of Virology discovered that the coronavirus shares more than 96 percent of its genetic material with a bat virus that came from southern China’s Yunnan province. This was published in Nature. Professor Wendy Barclay, chair in influenza virology at Imperial College London, said that most data so far “strongly support the idea that the novel coronavirus emerged through natural recombination and evolution of coronaviruses of bats.”

SARS Is Also Related

Additionally, SARS is distantly related to SARS (Severe Acute Respiratory Syndrome), sharing nearly 80 percent of the genetic sequence. Both diseases hijack the same lung cell receptors.

It Likely Occurred Due to Urban Sprawl

Experts still are not sure exactly how the coronavirus spread from bats and reached humans, but they assume that urban sprawl plays a role. It does not help that China has open-air markets that are loosely regulated. These are known as wet markets and also found in other Southeast Asian countries, including Vietnam and Indonesia. Because the wet markets have domesticated and wild markets, they can easily host many viruses. The animals are packed in close together, with secretions and dirt mixing.

This would also be far from the first time that these markets led to outbreaks, although the previous ones did not expand past the local areas. Additionally, over 49 of the first 99 patients were connected to a Wuhan market that sold wild animals.

There Are Many Coronaviruses

Although we are referring to this current coronavirus in a way that implies it is the only one of its, kind that is far from the case. There are a minimum of 200 coronaviruses found in bats worldwide based on a review in Viruses. SARS is another example of a coronavirus and in an analysis published in Plos Pathogens in 2017, scientists outlined finding coronaviruses with the building blocks of it in a cave.

What We Know About Its Jump to Humans

Although experts are reasonably certain that coronavirus originated in bats, they are still unsure how it jumped to humans. A new study in The Lancet in late January looked at ten of the genome sequences in the new coronavirus. They share more than 99.98 percent of the genetic sequence. Because of the large amount shared across patients, the virus likely only reached humans recently. Otherwise, it would have had more time to evolve, resulting in more differences.

There May Have Been an Animal in the Middle

The only caveat in the idea that the coronavirus originated in bats before spreading to humans is that it likely jumped to another animal between the two. This comes from the lack of bats sold at the market that many feel was the epicenter of the coronavirus outbreak. Some feel snakes may have been the missing link, while others feel it is unclear whether snakes can even be infected with the virus.

There Were Predictions of Another Outbreak

Interestingly, not only are bats a known carrier of viruses, but multiple experts had predicted another coronavirus outbreak or a disease similar to SARS emerging from the region. In March 2019, a study predicted a potential outbreak and in 2017, there was also a risk that said the risk of a disease like SARS is high due to the human spillover.

Bats Commonly Spread Disease

It is no secret that bats are known for spreading diseases to humans. In fact, disease ecologists who go into bat caves always do so while wearing full-body suits so they will not catch any diseases.

According to the U.S. Centers for Disease Control and Prevention, around three of every four infectious diseases in humans that is emerging originates in animals. Bats are a likely culprit for many of these diseases.

For example, bats were responsible for the Nipah virus outbreak in Malaysia in 1998 that killed more than 100. Infected fruit bats fed on mango trees over pig enclosures and their droppings infected the pigs, which people then contracted.

Bats were also responsible for the spread of SARs and are the original source of Ebola, the disease responsible for killing at least 13,500 people since 1976. They are also responsible for MERS (Middle Eastern respiratory syndrome) which is now in 28 countries.

People Keep Invading Bats’ Areas

The fact that bats carry diseases that pose a risk to humans is already problematic. It is made worse by the fact that humans keep spreading out, encroaching further into the territory of bats. Regions that were previously remote now have larger settlements, increasing the contact humans have with bats and other animals that carry viruses.

How to Prevent Contact with Bats

Whether or Not Bats Caused the Coronavirus, You Should Avoid Contact with Them

Whether or not it is every proven that the coronavirus came from bats, it is in your best interests to stay away from wild bats and to always wear protective gear when you approach them. A 2017 study found that bats have a higher proportion of the various zoonotic viruses compared to other mammals. They are an ideal host because they can fly over large areas and take diseases with them.

Do Not Visit Wet Markets and Do Not Seek Out Bats

The most obvious solution is to avoid visiting any wet markets that may sell bats or other infected animals, if you happen to visit a country where they exist. You should also avoid going to any other place that will have a large number of bats, especially wild ones.

How to Avoid Contact with a Bat Found Indoors

It is generally easy to avoid bats since they do not interact with humans. Sometimes, however, they will get confused and end up inside a building, like your home. If you find a bat in your home or indoors, do not touch it. Instead, call your local wildlife service or a professional bat removal service that uses humane methods.

Catching and Releasing

They will be don protective gear and catch the bat, then release it somewhere safe. You could theoretically do this yourself, but it is difficult without training and you do not want to come into contact with the bat if you can avoid it. If you wanted to try to catch it yourself, you should wait until the bat stops moving, then enclose it in a box or something solid against a smooth surface, slide cardboard over the edge to trap the bat, and then take it outside to release.

It Is Best to Call for Assistance

As mentioned, you could theoretically catch the bat in a box or something similar yourself and then release it outside, but you put yourself at risk of coming into contact with the critter. Because of the potential for disease, it is best to let a professional catch it. If you can, enclose the bat in a room until they arrive. Remember that bats can easily fit in very small holes that are just ¼ inch across.

Never Try to Kill or Trap Bats

No matter where you find a bat, you should never take steps to trap or kill it, as this will increase your chances of coming into contact with the mammal. You are likely to agitate the bat, which increases your chances of accidentally coming into contact with the animal, and there would also be a higher risk of being bitten.

Additionally, killing bats is illegal in most areas as they are protected species due to their positive contributions to the ecosystem.

Prevention Is the Best Strategy

The absolute best way to avoid coming into contact with bats is to prevent the critters from coming into your home. This way, you will not have to worry about evicting them or the creatures coming into contact with you.

Seal Up Gaps and Cracks Into Your Home

Bats will fit through any opening that is at least a ¼ inch by a ½ inch. As such, you need to ensure that you have sealed up any gaps or cracks leading into your home that are at least this large or larger.

This requires examining your home carefully to find any potential spots they could fit through. Pay close attention to attic doors, plumbing and electrical holes, and areas by windows, doors, and chimneys. Close them up with caulk, window screens, draft guards, and chimney caps.

Pay special attention to your chimney, making sure that you have a chimney cap in place and it features quarter-inch mesh so bats cannot sneak past it.

Monitor Your Home

As you can imagine, your home experiences wear and tear on a regular basis. Gaps, cracks, and holes form over time. Because of this, you will need to monitor and inspect your property regularly to make sure that no potential bat entry points have formed.

Use Light to Find Holes in the Attic

If you do not currently have bats in your home, you can also use daylight as a way to find potential entry points in your attic. Go up to the space during the day when the sun is shining and do not turn any lights. Wherever the sun pokes into your attic, you know that there is a hole or gap. You can then turn on a light to seal up those holes.

Change Your Outdoor Lights

If you live in an area where bats are a risk, then you can swap out the outdoor lights you use to make your property less attractive to them and keep them away so you avoid contact. Standard lights attract bugs, which are a staple in the diet of bats. As such, the bugs will attract bats to your home.

You can prevent this problem by changing your outdoor lights with yellow ones. These will attract fewer bugs, which makes your property significantly less attractive to bats.

Remove Standing Water

Removing standing water is another way to keep bats away so you avoid contact with them by eliminating their food sources. Insects breed on standing water, especially mosquitoes, which are among the favorite foods of bats.

In other words, eliminating standing water discourages insects and if bats do not have a readily available food source on your property, they are less likely to stay there. Your chances of coming into contact with a bat reduce dramatically if there are no bats on your property.

Do Not Rely on Ultrasonic Machines or Repellents

It may be tempting to use an ultrasonic sound machine or a bat repellent to keep the critters away and avoid contact with them. However, these deterrents and repellents will not work. Any situation where an ultrasonic sound machine works to keep away bats is just a coincidence and there were other factors that did the job.

The same is true of repellents, both homemade and store bought. You can find many suggestions of natural repellents online, but professionals who deal with bat removal will tell you that bats will ignore these. You will just be wasting your time, money, and effort by setting up the repellent without any noticeable effects.

How to Tell If There Are Bats on Your Property

The most obvious method of discovering you have bats on your property would be to actually see the critters flying around. However, you will not always see them so you will likely have to look for other clues as well.

Sounds in the Attic

Bats are most likely to take up residence in your attic, as it mimics the caves that they naturally roost in. If there are bats in your attic, you will likely hear rustling noises from the bats flapping their wings. Keep in mind, however, that unless you are a pro at identifying various animal sounds, the rustling may also indicate a different animal.

Because of this, the sounds in your attic are just a sign that you are likely dealing with some sort of wildlife. From there, you need to look for signs that it is actually bats.

Look for Droppings

In addition to actually seeing a bat, the other main indicator that there are bats in your attic or somewhere else is if you spot droppings. Remember to be careful when you notice droppings and do not touch them directly, since they are one of the primary methods by which bats spread disease.

Bat guano or droppings is usually in the shape of small and dark pellets. They will be slightly round and smell musky. You probably will not spot any bat urine, but you may notice the odor or stains.

Use Exclusion to Get Rid of Bats

If there are already bats in your attic, you can exclude them without coming into contact with the mammals. Ideally, you will hire a professional to help you with this process, since they will be able to do a more effective job.

To exclude bats, you would seal up nearly all of the entrances into your attic or other space. Leave the main one open and cover it with bird netting or something similar that allows bats to leave but not get back inside. Wait until all of the bats have left and then permanently seal the final gap.

Finding Entry Points

The act of finding entry points and sealing them up is easier said than done. Professionals have a few tricks that can make it easier to find these spots. One option is to wait until dusk and watch for the bats. You should be able to see where they leave from.

Do Not Exclude Between May and August

Even if you think there are bats in your attic, do not perform an exclusion to get them out between May and August as this is breeding season. If you excluded the critters at this point, it is possible that not all of them could fly yet. This would result in you excluding the adults and leaving the young bats trapped inside to die of starvation or fight to get into your house.

Avoid Contact with Bat Waste As Well

As mentioned, bat droppings are one of the primary means by which these creatures spread disease. Because of this, you need to be extra careful when cleaning up bat droppings on your property. This is particularly true if you have just excluded multiple bats in your attic or another location, as there will be larger quantities of waste.

Wear Protective Gear

Before you clean up any bat waste, you need to don protective gear. At the minimum, where thick rubber gloves, a respirator or facemask, and eye protection.

How to Clean

Start by physically removing the droppings with a plastic scraper or vacuuming them up. Then, use an enzyme-based cleaning solution on the area. These solutions break down any biological waste products that remain.

Hire Someone

Ideally, you will just hire someone to clean up bat waste. Professionals know how to do so safely in a way that minimizes the risk of particles entering the air and spreading disease.

Other Diseases that Bats Transmit

The risk of you contracting coronavirus from a bat is incredibly low, especially if you are not close to the epicenter of the outbreak. However, there are some other diseases that you could potentially get if you come into contact with a bat or bat guano.


Histoplasmosis is a type of respiratory disease that a fungus called Histoplasma capsulatum causes. This fungus occurs in bat droppings and it produces spores. If the bat droppings are agitated or touched, the spores become airborne. Humans can become infected just from inhaling those fungal spores.

Histoplasmosis starts with flu-like symptoms, combined with potential effects to the heart, hearing, and vision. If you do not catch and treat it, histoplasmosis can also lead to blood abnormalities, fever, pneumonia, or even death.


Only a small percentage of bats carry rabies, but the risk still exists. If a bat has rabies, it will be very sick and behave abnormally, increasing your chances of coming into contact with it.

The good news is that bats are unlikely to attack you, unless you try to attack or capture them. Rabies is particularly scary since the disease is almost always fatal once the symptoms begin to develop. You can, however, receive a rabies vaccine before the symptoms begin to appear.

As Long as They Are Not in Your Home and You Do Not Come into Contact with Them, Bats Are Harmless

You definitely do not want bats in your home and you should take steps to avoid coming into contact with them as well. That said, as long as you just occasionally see a bat and they are not living inside your home or coming into contact with you, they are usually harmless.

Bats are extremely unlikely to approach or attack humans. The exception to this is if you attack them or attempt to capture them.

Additionally, bats are very good for the ecosystem and they help control mosquito populations. Given that mosquitos are another pest that spreads disease, this is an important role.

The Caveat: Their Guano

The caveat to the idea that bats are usually harmless is their guano. Since their guano can transmit disease, you do not want to be able to come into contact with that either. As such, having an occasional bat on your property is fine, but you probably do not want an entire colony roosting nearby. Otherwise, that colony would likely leave a lot of waste that potentially contains diseases.

The Bottom Line

It is extremely likely that the coronavirus came from bats, but those mammals likely spread it to another animal before it was passed to humans. Bats are known for carrying diseases, including multiple coronaviruses in South Asia. For your safety, it is best to avoid contact with bats and bat guano, which also carries the disease. Some simple home modifications should be enough to keep bats out of your house. If you see a bat on your property, contact a professional to safely exclude it.