How to...: September 2014 Archives

Ants and Disease

Hello, this is a very strange situation but I have a 10 month old baby in my home and I am concerned.

A couple of weeks ago I went in to the backyard and noticed my dog was playing with something unfamiliar. As I walked towards it I realized that it was a bird. This bird must have been there for awhile because it was unable to move, and had defecated so much that ants were (I'm sorry for the graphic details) actually crawling inside of this poor bird and apparently eating the fecal matter. This poor guy was obviously in a significant amount of pain so we had to do something very sad to stop it from suffering any longer.

This just so happened to have occurred next to a wall in our home that is the exterior wall to our dining room where we eat and where my 10 month old's high chair is. Today, I was eating at our table and some of my paper work and pens were sitting on top of it. As I was picking up my plate I noticed the same species of tiny little ants crawling all over the table and my paper work. There was not even any food or anything on the table that could have lured them there. I instantly took my son upstairs, and began disinfecting the table, vacuuming and such.

I do not know anything about ants but my concern is that these ants might be carrying disease from the bird. Can you please tell me if I need to be worried about this? They are the tiniest little transparent orangish colored ants. We live on Oahu, in Hawaii. Thank you very much for your time.


Ok, Alix. I've got good news and bad news.

The bad news: Ants (just like any animal that moves from one place to another) can transmit infectious bacteria, including Salmonella and Staphylococcus. (I'm not trying to throw your dog under the bus by any means, but your dog is definitely more of a vector for bacteria coming in from outside than these ants.) As indicated in a quick literature search (click here ), it's been reported at least as far back as 1914 (Wheeler) that if an ant walks through an area densely populated with infectious bacteria, they track it along in quantities large enough to show up in a petri dish.

The good news: Petri dishes don't have immune systems. The quantities of bacteria ants transport and slough off as they saunter across your counter tops will probably be small compared to the infectious dose for healthy humans. The quantities of bacteria that remain on the ants' feet after taking the thousands of little ant-steps between a source of infection and your table would presumably knock off the vast majority of the bacteria, leaving too few to constitute an infectious dose.

So what I'm trying to say is: thought it is theoretically possible for ants to transmit infectious bacteria to humans, as far as I'm aware (other members of this blog, please speak up if you know better!) there are no records of ants being definitively implicated in someone catching a disease. As best as I can tell, all of the articles that reference ants' potential to be vectors for infectious bacteria are based upon laboratory studies in which nothing besides some agar in a petri dish got sick. Ants, as you know, are quite common, so it seems to me that if they were serious actual (as opposed to potential) disease vectors, we'd have heard about it.

A well-intentioned tangent: This is, of course, neither a child-rearing nor a health advice blog, but I think this recent article on the "Hygiene Hypothesis" makes a good case for not keeping too sterile a house:
Some arguments, both pro- and con- Hygiene Hypothesis haven't been rigorously scientifically tested, so take everything you read with a grain of salt...or a pinch of dirt.

Hope this helps!
Jesse Czekanski-Moir & the AntAsk Team

Ants in concrete foundation

Hi - and help!?

We live in Northern Alberta, Canada. Over a year ago, we discovered ants - lots of ants - coming up into our furnace room through a crack in the concrete foundation of our basement. My husband put poison down the crack and seemed to work very well, getting rid of them and not coming back. Until now.

Last night he went to check - as he does periodically - and now they are large ants coming from the same crack in the concrete. He again put poison down the crack, and vacuumed up the few dozen (he may have been lessening the amount to avoid my freak out). My daughter's bedroom
is right beside the furnace room. She went to bed last night - only to be woken up by something flying and hitting her in the guess is a flying queen ant.

Please tell me what we should be doing to ensure we have gotten to the bottom of this ant problem. Should we get the crack filled? Will they find another place to come in? In order to get access to this part of the foundation concrete, they have to be coming in very deep under the back yard as that part of the foundation must be at least 6 feet underground.



Hello Cathi,

Thanks for writing to the AntBlog!

Ants are an important part of the natural world, and play a great role in an ecosystem. Their extreme diversity and abundance, wide spectrum of biology and interaction with other groups of organisms, make them affect the pattern of distribution and abundance of plants and other animals. The good news is that this is also applicable to your home environment: ants will control populations of other housemate arthropods, like spiders, fleas, clothes moths, bed bugs, and so on. We can also learn a great deal with ant behavior (to see how ants have inspired human societies, take a look here).

Full face view of Polyergus breviceps, a slave maker ant species that occur in your area (image by Shannon Hartman/ See more on how it makes slaves here.

So, if it were my home I would just control their population, prevent them from accessing my food, and marvel myself with them crawling around. Procedures like proper food storage and waste management, and daily surface cleaning, will reduce the number of ant workers indoors.

However, if you really cannot live with those wonderful creatures, I think the most effective way to prevent them from accessing your home would be to seal the cracks (you can use clear silicone, or other sealant).
Please, note that commercial sprays are ineffective against ants, killing just the foragers, while the rest of the nest (deep underground) continues intact. Poisoned baits generally work well to eradicate ant colonies (workers feed on the bait and take it back to the nest where they share it with their nestmates), but this approach may take several weeks to several months to produce an effective result. You can read more on baits here.

We hope it helps,

Flavia Esteves & the AntAsk Team

Neighborhood ant farm?!

I have an ant infestation in my house and I have just begun terro traps. I have already attempted an ant killer by black flag but unfortunately that failed because they weren't attracted to it. I was speaking with one of my neighbors today and it seems that they have the same issue. Also the same issue for a neighbor that lives a street over. I'm worried that the traps are nothing compared to the abundance of ants. Any advice on getting rid of them?


Dear Cortney,

Thanks for writing! Regarding your question: since your traps are not attracting the ants living in your house, I would try something like a cafeteria experiment. It consists of offering them an array of food items that they might eat on (e.g. peanut butter, jam or jelly, and tuna). Once you discover which item works better, add the appropriate poison, and set the traps. You will find really important information on traps and baits here.

However, ants are quite important for our surrounding environment, providing services like bringing nutrients to the surface of the soil, aerating the soil, dispersing seeds, and predating pest species. Many of them are beautiful too (like our special guest here). I hope you will fall in love with them while observing their interactions on your baits, and find a way to coexist with them!

I hope this helps,

Flavia Esteves & the AntAsk Team



I stumbled upon your site while googling 'how to make peace with your ant infestation' (there seem to be no suggestions on that, by the way). I thought perhaps someone could offer advice for our particular situation.

I live in south Florida. In March, my husband and I bought our first house. Before closing, I did see a pile of dead ants in a corner of the family room, but the home inspector's report didn't find signs of any infestation, or at least 'wood destroying organisms'.

Once we moved and settled in, I began to realize that there were serious ant colonies on the property, and noticed ants in the Florida room, also in one of the bathrooms. I think in the beginning, they were all dead ants on the window sills and in that bathtub. As summer progressed, the problem got a bit worse. They can walk right through our windows and front door.

I did a bunch of online research, and I'm thinking they are carpenter ants. Not as big as the ones up north, but carpenter seems to fit the description. Because I have a toddler and two cats, my first line of defense was a borax/powdered sugar mix. I scored a big hit when I found old timbers half buried in the front yard near the walkway and removed them, and also pored boiling water at the foundation under a window in the back. We also replaced the weather stripping at the front door, and I've been caulking baseboards and around windows. For about a week, maybe two, it seemed like I was making some real progress, however this morning I saw ants swarming again out front in the morning. Late this afternoon I noticed ant hills surrounding potted plants in the back (near the house). I shook the pots a bit, and ants also started swarming out of the pots, up the trellis, and carrying eggs up into a previously unseen hole in the eave. Great.

I'm not positive, but I think the ants I've seen over the last few days are smaller than the originals, so maybe these little guys have stepped in to fill the void of the bigger ones. Regardless, we have ants in our walls, and apparently in our attic. I know that to truly keep these guys out we have to replace some rotting wood at the door in the back, but our windows are so old that they can literally crawl right through them - the windows themselves, not gaps around them. I have a little one and a couple critters that prevent me from putting down serious poison, and our budget is falling a bit shy of relaxing the doors and windows.

Is there any advice you can give on how to begin to win this battle? The house was empty for a long time, and the responses of ants in different areas let me know that's it's a big ass colony, or that the satellites have close communication.. Any hope you can give me is greatly appreciated-


Dear Alyssa,

Thanks for writing! I am glad you are still trying to make peace with ants that live in your house. Most ants are beneficial for our surrounding environment (including yards) - they actually rule our terrestrial world: cycling and bringing nutrients to the surface of the soil; aerating the soil; dispersing seeds; predating pest species, among many other "services". Also, children generally like to spend time observing ants just pass by, or being attracted to a bait, and it can stimulate their curiosity towards our natural world. You can read more about how good ants are here.

If after all you think its better to get rid of your crawling roommates, you should know you are already doing some of the most effective things to eradicate them from your home, and here you will find important information on baiting. Further, you can drown ant colonies in the plant pots, using warm water, and leave some clove sachets in strategic areas of your home (like in the food shelves) to repeal them.

If you really have carpenter ants, this may indicate you have a more serious problem, because they often build nests in compromised wood. I would first be sure they are really carpenter ants - try this and this for identification; and, if positive, you can try this to eliminate them from your place.

Please, look for more tips here, and have a good lucky in your endeavor!

Flavia Esteves & the AntAsk Team