Coronavirus in Local Bat Populations
What Could Happen and What to Do
Because bats often turn up inside homes, homeowners need to be aware of Coronavirus-related risk and problems and how it could affect them and our bat species. Earlier this year, I received letters from state game agencies in both Tennessee (TWRA) and Virginia (VDGIF). The theme of both were similar. Both of our local game agencies are concerned that Covid-19 could enter our local bat populations. Adjustments have to be made to the handling of bat in the house and attic bat situations. Home owners need to be made aware of this. Unfortunately, Covid-19 is going to make bat removal an entirely different affair.
Covid-19 is (or was) endemic to bat species in China. For a local bat to contract this new virus they would have to somehow make contact with a Chinese bat infected with the Coronavirus which, to this point, was restricted to another continent. Fortunately, none of our bats migrate to China so transmission between the continents did not occur. Our bats were protected by the vast expanse of our oceans and other geographic barriers. There was no possible way for the virus to enter our local bat populations...until now.
Background – Human/Wildlife Disease Crossover
Wildlife species all have their own species-specific list of diseases that they carry. If the disease has been present for a while, the population has probably developed a resistance to that disease and it is not that likely to cause major problem. However, the problem comes when that disease crosses over from one species to another (and that includes humans) that have not developed resistance to that disease. This is something that wildlife control and management professionals are trained to consider in their work every day. This is exactly what has happened in Wuhan, China. “Wildlifers” know that once a new pathogen is in a population it is hard to impossible to control.
How Would the Disease Cross Between Humans and Bats?
Each year thousands of people across the United States find a bat inside their home. Usually the bat is noticed as it flutters in circles around a room or hanging on the drapes. People in this situation find themselves searching a lot of different questions like: “How do I get rid of this bat” and “Could this bat be rabid”. This year is different though. People who find a bat in their house will also have to consider transmission of Covid-19 between humans and bats.
There are probably millions of homes across the country that are host to bat maternity colonies. The females choose to do this because attics present a predator-secure roosting spot that will keep their furless babies warm at night. It also presents an entry point that is high enough off the ground to make entry and exit easy. (Something that is important to a momma bat.) In late summer, bats tend to occasionally wander down and find their way into the house where they encounter people. This is when the trouble is likely to start, so I am writing this article to make the public aware of the possibility of a surprise turn of events in our local bat fauna and necessary precautions to be made.
Local Bats May Be Susceptible
Normally, wildlife professionals are concerned with diseases that could cross from wildlife to humans like Rabies, Hantavirus, Salmonella, etc. In this case, however, things are much more complicated. Infection would not start from bat to bat contact. Early in the process, we are more concerned with the prospect of humans infecting the bats. This would happen when people and bats came into contact and the disease were transmitted to a bat from an infected person. If this happens, all bets are off. Research is currently being done and all we really know is that our local bats can carry other types of Coronaviruses. This suggest that our local bats would be susceptible to the new virus that has entered the country. This is cause for great concern. Covid-19 may enter our local bat population and then create serious problems for humans and bats.
Midsummer – When People and Bats Begin to Meet
Once we reach midsummer, the semi helpless pups start to move around a little more. This makes it more likely that they fall from their roosting areas, crawl around, and accidentally wind up inside the home with the human residents. Usually there is some wandering in the attic and a small hole of some type is found, with a draft blowing through it, and the bat follows it looking for an escape. Once this happens, momma bat may decide to follow the youngster and could also wind up inside the home. Nearly mature bats, like human teenagers, make mistakes and also turn up inside a home. Fully grown adults can also become disoriented and end up inside the living spaces. At this point, the homeowners may discover the bat and this is the moment that game agencies are concerned about. Infected homeowners may decide to handle the bat and it may become sick. Once the bat is returned to the wild, it will return to its colony and infect the entire colony. From there, the disease is likely to cross between colonies.
What happens if Our Bats Get Infected?
There are three possible scenarios:
Bats themselves could be unaffected, but they could become a reservoir for the Coronavirus which would have the potential to re-infect humans.
Nothing. Hurray! Our bats may not be affected by the virus and it may have no impact at all. Obviously, this is what we would like to see happen.
Bat species could be wiped out. Like humans, our local bat species have never been exposed to the coronavirus and it could have severe impacts. Like so many other things with this pandemic, we are waiting to see what happens and scientist are currently studying this problem.
Like I have already mentioned, we do know that our local bats are susceptible to other coronaviruses, so we have to be vigilant and take precautions. If Coronavirus has deleterious effects on bats like it has on humans the consequences could be severe. Please use caution when you encounter bats.
Bats and Pharaohs Plague
Fundamentally, all our local bats are insect predators. Generally speaking, predators do two things that help manage prey populations:
They depress prey populations - Basically, some of the prey biomass gets converted to predator biomass, and it takes a lot of prey to support a population of predators. Simply stated, bug predators like bats mean fewer bugs. Not just a few less, lots less...like millions of tons less.
Predators help stabilize prey populations - Generally speaking, whenever food is abundant predators eat more and as a result, are able to raise more babies. More predator babies means that you have more predators eating bugs. In a nutshell, more prey leads to more predators which leaves you with fewer prey animals...a self-maintaining loop that goes on forever. Break the loop and things can be a bit crazier than before. Insect populations can fluctuate. Maybe we would have swarms of bugs like we never saw before...who knows.
Again, I can’t stress enough that, if we lose a means of natural insect control this could mean that insect populations would be higher and might tend to fluctuate more. I personally don’t like the sound of this. I really don’t want a “Pharaohs Plague” of bugs to attack our crops. One plague per lifetime is more than enough for me. I don’t want this for my children either. If your would like to read another source on this topic, I would recommend seeing the Bat Conservation International Page on this topic.
Potential Impacts on Agriculture and Our Health
If Coronavirus does wipe out bat species this could have major impacts on human lives. You may be surprised how serious this could be. After all, how do we benefit from bats? Well, all our local bat species are insect eaters. They feed on any night flying insect including mosquitoes, beetles, and moths. Some of these insects are crop destroyers and humans receive direct benefits from their nightly activities. It is nearly impossible to exactly quantify the volume or importance of insect control to agriculture, but it is massive. The volume of destructive insects consumed each year would have to be measured in tons not pounds. Loosing this natural insect control would probably result in increased use of pesticides which could in turn result in increased cancer rates. Unfortunately, though, we will only truly know how important bats are to us once they are gone and then it will be too late.
Questions You Should Consider
It is impossible to accurately forecast the impacts of Covid-19 entering the local bat population at this point. Sadly, all I have for you are more questions. These are probably questions that you have not considered up to this point, so I will share my thoughts so that you can have at least a little better understanding.
Does the bat in my house have Covid-19? - I can't answer that for sure. It is early yet, so I would guess that it has not had time, but that is just a guess. It is impossible to say if bats have had time to get infected or how fast it would spread between colonies.
Covid-19 could wreck multiple bat populations - This is the worst-case scenario. It is logical to assume that our local bat species are no less resistant to Covid-19 than we are. This is a new disease for them just like it is for us. It is impossible to predict the outcome. It could have no effect on them or it could be devastating. Effects could range from the loss of entire species to no loss at all.
Insect population surges – Across the U.S. bats eat millions of tons of insects. They feed on a vast selection of night flying insect pest species including biting (mosquitoes) and crop destroying species. We don’t really know how much bats do for us. If they disappeared, what would happen? Increased pest insects would require increased use of pesticides and no one wants that. Increase pesticide use could conceivably cause an increase in cancer rates.
Now the Important Part
What Can You Do to Prevent This?
Don’t infect the bats. This will mean:
Preferably, call a professional to deal with your bat problem. I am glad to come out on short notice to help out. Removing bats from an attic is not a skill most people have even in a good year. I hear stories from clients about how they tried to remove their bat colony and they almost always make some key mistake. After all, this is why I was called in.
If bats must be handled, use personal protective equipment including face mask, gloves, etc.
Use face mask, gloves, and other personal protective equipment when working around entrances to attic colonies.
Sanitize work areas when work is done around roost entrances.
Do not venture into caves where bats may be roosting or hibernating. In fact, caves on state wildlife areas are closed to the public. It is probably a good idea to stay out of caves on private property also.
Stay out of attics where maternity colonies may be roosting. Respiration or contact inside roost areas can bring infection to the colony.
Avoiding handling bats that are found inside or outside of the house.
If you feel sick stay clear of bats.