Botflies are parasites that can infest animals, including dogs, by laying their eggs on the skin.
These eggs hatch into larvae, which burrow into the animal’s skin, causing discomfort and potential health issues.
Learning how to detect and safely remove a botfly larva from your dog is essential for maintaining your pet’s health and happiness.
It is important to monitor your dog for signs of a botfly infestation, such as swelling, redness, or an open sore with a breathing hole.
If you suspect that your dog has been infested by a botfly, consult with a veterinarian immediately for proper diagnosis and treatment.
Remember that attempting to remove a botfly larva on your own may harm your dog and increase the risk of infection, so seek professional help.
Understanding Botflies and Their Lifecycle
The Botfly Lifecycle
Botflies, also known as cuterebra, are parasites that attack mammals, including dogs. Their life cycle has four stages: egg, larva, pupa, and adult.
Botflies lay their eggs near rabbit burrows or other small animal dens, where the larvae can easily latch onto a host.
Upon contact with the host’s body heat, the eggs hatch, and larvae burrow under the skin, forming small breathing holes called warbles.
After some time, the larvae drop off the host to complete their life cycle, forming pupae before emerging as adult botflies.
Rodent bot fly pupa
Adult botflies, unlike typical flies, have a bee-like appearance and possess rudimentary or non-functioning mouthparts, as they do not feed or take in nutrients during their adult stage.
They exhibit a high degree of host specificity, which means they only parasitize a small number of host species.
Identifying Botfly Infestation in Dogs
A botfly infestation in dogs, also known as myiasis, occurs when the larvae of the botfly attach themselves to the dog’s skin.
Identifying this type of infestation in your dog can help you seek timely treatment from a vet.
Common symptoms of botfly infestation:
- Bumps or lumps on the skin
- Fur loss around the affected area
- Infected wound or cysts
Botfly infestation in dogs is usually characterized by the presence of warbles.
Warbles are bumps caused by the larvae burrowing into the skin, often resulting in pain and discomfort for the affected dog.
These bumps may vary in size, but they are generally firm to the touch.
Dogs with a botfly infestation may display signs of discomfort, such as scratching, lethargy, loss of appetite, and sneezing. In some cases, botfly larvae can migrate to other parts of the dog’s body, causing more severe symptoms.
For example, if the larvae reach the dog’s nose or eyes, the dog may experience discharge and sneezing.
In severe cases, the parasites can even reach the dog’s brain, causing serious neurological symptoms. This is why timely detection and treatment are crucial.
To identify a botfly infestation in your dog, closely examine their skin for unusual bumps or swelling.
Check for fur loss and skin irritation, as these may indicate the presence of a botfly larva.
If you suspect an infestation, consult your vet for a proper diagnosis and to discuss treatment options.
Remember, identifying a botfly infestation in your dog is the first step to ensuring their health and comfort.
Pay attention to any physical abnormalities or changes in behavior, and consult your vet if you notice any signs of myiasis.
How to Get Rid of a Botfly in a Dog: Removing a Botfly Larva
If you discover a botfly larva in your dog, do not panic. Here are some steps to safely remove it:
- Visit the vet: It is always best to consult with a veterinarian as they are trained in handling such cases and can provide proper advice.
- Manual removal: If you decide to remove the larva at home, make sure to have all the necessary tools, such as tweezers and forceps.
- Prepare the area: Clean the area surrounding the hole where the larva is located. Ensure your dog is relaxed and comfortable.
Bot fly maggot
To proceed with the removal, follow these methods:
- Suffocate the larva: Apply petroleum jelly over the hole to suffocate the botfly larva, which then can be safely removed with tweezers or forceps.
- Manual removal: Gently grasp the larva with forceps or tweezers without crushing it, and slowly pull it out whole.
Please note that the procedure might require anesthesia if the dog is in pain or uncomfortable.
After removal, keep an eye on the wound and monitor your dog for any signs of infection. If complications arise, consult your vet immediately.
Pros and cons of removal methods:
|Suffocate with jelly
|Non-invasive, less pain for the dog
|May take more time
|Faster, immediate relief for the dog
|Risk of crushing larva, causing infection
Remember, when dealing with botfly larvae in your dog, it is essential to keep calm and act responsibly.
Consulting your veterinarian is always the safest option.
Treatment and Prognosis
The first step in treating botfly infestation in dogs is to remove the larva carefully. Some common methods include:
- Using forceps or tweezers to gently extract the larva
- Covering the wound with petroleum jelly or tape to suffocate and force the larva out
After the larva is removed, it’s essential to clean and disinfect the wound. This prevents any secondary infections caused by bacteria entering the wound site. For this, you can:
- Clean the wound using mild soap and water
- Apply an antibiotic ointment to the wound
In some cases, your vet might prescribe oral antibiotics to prevent infection. Pain medication and anti-inflammatory drugs might also be prescribed for your dog’s comfort.
Sometimes, a more extensive surgical intervention might be required, depending on the location and severity of the infestation.
In rare cases, complications such as blindness, spinal cord damage, and abscess formation may occur, requiring additional medical attention.
Here’s a quick comparison of different treatment methods:
|May not work on deeply embedded larva
|Takes longer, not always successful
|Effective in removing deeply embedded larva
|Invasive, may require anesthesia
To ensure a favorable prognosis and prevent re-infestation:
- Keep your dog’s living environment clean
- Groom your dog regularly
- Prevent exposure to wildlife and areas with high botfly activity
In summary, treating botfly infestation involves larva removal, wound cleaning, and medication.
Prognosis is generally good if done promptly and correctly, but in some rare cases, complications may arise.
Prevention and Protecting Your Dog
One way to prevent bot fly infection in your dog is to avoid areas with high rodent populations.
Bot flies require a host, often rodents, to complete their life cycle. By steering clear of these areas, you reduce the likelihood of your dog or cat coming into contact with bot flies.
Regular grooming and inspections of your dog’s skin and fur can help you detect any wounds or abnormal lumps early. Prompt attention to such findings may prevent an infestation from developing further.
During the summer months, when bot fly infestations are more common, keep your dog’s outdoor play in well-maintained, short grass areas. This minimizes exposure to bot flies and other potential parasites.
Make sure to schedule regular vet check-ups for your dog. A vet can monitor your pet’s health and detect any unusual signs such as vomiting, bleeding, or swelling, which could be indicators of a bot fly infection.
For dogs that enjoy hunting, take extra precautions. Hunting dogs are more prone to encountering bot flies due to the nature of their activity. Investing in protective wear like neck guards is a good idea to limit their exposure to bot flies.
By following these tips, you can help protect your dog from the dangers of bot fly infestations and ensure that they remain healthy and happy. Remember, prevention is always better than dealing with an active infection.
Botfly infestations in dogs can be distressing for both the pet and the owner.
Understanding the life cycle of botflies and recognizing the signs of infestation are crucial for timely intervention.
While manual removal is possible, seeking veterinary care ensures the safety and well-being of the dog.
Regular grooming, avoiding high-risk areas, and routine vet check-ups are essential preventive measures.
By being proactive, dog owners can protect their furry friends from the discomfort and potential health risks posed by botflies.
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about bot flies. Scroll down to have a look at some of them.
Letter 1 – Rodent Bot Fly Maggot (and it’s edible)
These grubs or insects showed up in my cabin along with a dead squirrel the cat brought in. Could be that its a coincidence or perhaps the cat brought them as an additional gift.
The insects were not on the squirrel. Can you help me identify these so I can decide weather they a friend or foe.
Rick in Western Colorado
Here is one sure to gross out our readership. These are Rodent Bot Fly Maggots, Cuterebra species. The Rodent Bot Fly is a mammalian endoparasite. According to a website we located: “The female flies will lay their eggs along rabbit trails and near rodent burrows.
The first stage larvae will hatch and quickly attach to hair when a host brushes against the egg. The larvae then burrow into the skin and leave a breathing hole. ” Also on the website is the information: “Cuterebra is a normal bot fly of rodents and rabbits, but can also infect cats, dogs, and man.
The adult fly looks like a bumblebee and is rarely seen. It may appear a shiny blue or black color. The third stage larva is dark brown to black with stout black spines. ” Your close-up photo shows the mouth hooks of the maggot, substantiated by this image on BugGuide. B
ot Flies are also known as Warble Flies due to the lumps visible on the skin of the hapless host. There is also a Human Bot Fly, Dermatobia hominis, that is found in Central America.
Wolves on Rabbits
After just reading your description of the bot fly larvae, I’m wondering…at certain times of the year (usually late summer, early fall) when my father would go rabbit hunting, (we actually depended on them for food in the ’50’s), they would sometimes get rabbits with what they then called ‘wolves’ in their necks and we were not allowed to use them for a food source.
Could it be that I’ve learned after all these years that these were actually bot fly larvae? I large lump would most times be visible. Does this actually damage the meat for human consumption? Thanks for taking the time to read my query and if you have time to answer, that would be great, but if you don’t, I understand…. Sincerely,
Pat, Hawk Point
It sounds like your rabbits with wolves were parasitized by a Bot Fly. The meat near the wolf or warble might be unsavory, but cooking the meat would definitely kill the parasite.
Joanne Gets Sick!!!(08/15/2007) The Rodent Bot Fly
Will you pay for cleaning my nice leather recliner cuz I just barfed on it.
Close Encounter with a Human Bot Fly!!!
(08/15/2007) Human Bot Fly experience
Hello fellow bug-nuts,
Your recent posting of the rodent bot fly larvae brought back some interesting memories. I brought an unexpected souvenir home from a trip to Costa Rica in ’00. You guessed it. Luckily, I’d read about these critters. Made me the hit of my local doctor’s office.
I actually printed a page from a Canadian website and brought it along in to prove I knew what I was talking about. It is a very weird sensation to feel these beasts move when they’re in your flesh (mine was in the flab of my upper left arm). You can actually feel the bristles they anchor themselves with as they twist about.
The research I did told me the adult female bots actually wrestle a mosquito down and lay an egg on the mosquito’s abdomen. Then the mosquito bites a host, the egg on her belly hatches (very quickly, apparently), and the newborn enters the mosquito’s bite site.
My research also gave me the bot’s larval timeline, so I knew how long I had, and how insistent to be at the doctor’s office. Love your site! I check it every day.
Don J. Dinndorf
St. Augusta, MN
Bot Fly Larvae are Edible
edibility update on bot fly
Just to keep the gross-out fest going, and to answer Pat’s question: I’m pretty sure that NO, the presence of bot fly larvae would not render the host animal inedible. There’s a good deal of documentation [as recent as 1918] of Inuit hunters taking down caribou that were infested with large fly larvae, and then making a point of cooking and eating the larvae first.
Not sure if I could do it, especially considering the textural issue of those rough, stubble-like projections all over the larvae’s sides, but the point is that if some people enjoyed eating the actual flesh-consuming maggots, then eating the rest of the animal would not be a big deal. Reluctance to do so is pure ‘fussiness’ on our part. Best,
Letter 2 – Rodent Bot Fly Pupa
What the Hell is This!!!
This is probably one of the sickest stories you’ll come across.. It was like a scene out of “Aliens”. This morning, I came across our pet greyhound, Merlin, calmly sitting in our family room, with what appeared to be a rather large, dead rat in his jaws!!! He immediately dropped it, once I told him to.
Our back yard, while fenced in, is bordered by wooded areas. Consequently, we do get the occasional mouse or rat in the yard. The rat, upon further inspection was not dead. It was fairly mangled up and appeared to be taking its last gasps of air. I grabbed a plastic bag and like picking up dog poop, grabbed the rat by the tail and took it out back.
My wife, by this time, had joined me and the initial shock of finding such a large, disgusting “present” in the house had slightly abated; we were quite impressed by its size. As I turned the rat around by the tail, I thought I was looking at internal organs that were beginning to “protrude” through the puncture holes and small lacerations on the rat’s body. . . .
To my and my wife’s horror, we realized that these were not organs, but large writhing “things” (grubs, worms, maggots)!!!!????, boring their way out of the body. I quickly disposed of the “present”, but not before one of the things in question, dropped to the pool deck, where I scooped it into a plastic bag for identification. . . .
Since we have no idea what this thing might be, my wife is now worried that our beloved grey may have swallowed or eaten one of these creatures and that at this very moment, it is making a lovely home for itself and its larvae in the body of our greyhound.
Doubtful, but I am passing along the concern. If you can make out the picture, it is segmented and colored a dark- greenish black. Tried to identify it myself, but had no luck. Hope you can help.
Palm Beach Gardens, Fl.
Based on just your vivid description, we would identify your creature as a Rodent Bot Fly, Cuterebra emasculator. This fly which resembles a Bumble Bee lays its eggs indirectly on habitat and the warmth of the rodent body causes the eggs to hatch and the maggots to attach to the host animal.
The maggot then enter the rodents body through an opening, either being licked inside or by boring through the eye membrane. It then settles beneath the skin and forms a warble, a type of pimple through which the parasite can breath and excrete.
The parasite is rarely transfered to another host, and the risk to predators is minimal. Just to add to your nightmare, there is also a Human Bot Fly, Dermatobia hominis, reported from Central America.
We have not been able to locate a photo of the Bot Fly Pupa, but your image is consistant with fly pupa, and the supporting story lends credance to our identification.
Letter 3 – Rodent Bot Fly
huge black fly
August 6, 2011 10:55 pm
I live in the country. Eagle creek Oregon. Found this in the laundry room. Its huge! All black. Little wings on top of its shoulders. Is it a horse fly? I’ve never seen a fly this huge before. Its crawling on a quarter!
This is a Rodent Bot Fly, and we believe it is Cuterebra tenebrosa which we identified on BugGuide. These Bot Flies are skin parasites on rodents, and the host insect for Cuterebra tenebrosa is the wood rat.
Letter 4 – Rodent Bot Fly Pupa
Location: NE Pennsylvania
September 11, 2011 11:34 am
This is one of the strangest bugs I have ever seen. It appears to be some kind of grub as it has no feet. It moves slowly using a wave technique. It has two puffy orange objects by either its head or bottom.
We found it under our kitchen table. My mom thought it was a terd! It is almost black but a bit lighter nearer its orange orbs. We would love to know what this is
Signature: Thank You
This is either a Pupa or a Pre-Pupal Larva of a Rodent Bot Fly in the genus Cuterebra which you can verify by comparing to this photo on BugGuide. The mystery is how it go under your kitchen table. Perhaps your household feline recently caught a rodent that was being parasitized by this endoparasitic Bot Fly.
Species Identification Courtesy of George Jeff Boettner and Eric Eaton
Can you copy and paste this to WTB?
George Jeff Boettner commented on your link.
George Jeff wrote: “Hi Eric, I can’t seem to post to the original site. If you can let them know this is a mouse bot, Cuterebra fontinella.
It likely emerged out of a mouse walking across the table. So they should look around for signs of mice too! If put in soil and kept dry and outdoors for a year, they would likely get an adult bot next July or August.”
Letter 5 – Rabbit Bot Fly
Location: Dallas, TX
October 17, 2011 9:53 pm
I’ve lived in Dallas, TX for 40 years and have never seen such a thing. Found today on our hydrangea plant. It has a fat head, thorax & abdomen, is mostly black with awesome horizontal red stripes across the top of its huge eyes, has white fuzz between the thorax & abdomen, and it’s wings fold in a crossed fassion, unlike most flies.
Its legs are just like a common house fly (only larger) and it rubs them together and walks/behaves like a fly. When it flies it sounds loud like a bee. It’s about an inch long!
This amazing fly is a Rodent Bot Fly in the genus Cuterebra, but alas, we don’t recognize the species. It doesn’t seem to match any of the species posted to Bugguidewhich describes the life cycle as:
“Females typically deposit eggs in the burrows and ‘runs’ of rodent or rabbit hosts. A warm body passing by the eggs causes them to hatch almost instantly and the larvae glom onto the host. The larvae are subcutaneous (under the skin) parasites of the host.
Their presence is easily detected as a tumor-like bulge, often in the throat or neck or flanks of the host. The larvae breathe by everting the anal spiracles out a hole (so they are oriented head-down inside the host). They feed on the flesh of the host, but only rarely does the host die as a result.”
GIANT Fly – much better picture!
Location: Dallas, TX
October 17, 2011 10:30 pm
Please refer to my previous submission today.
We will add this to the posting we already created for your amazing beautiful Rodent Bot Fly which we now believe to be a Rabbit Bot Fly, Cuterebra buccata, based on photos posted to BugGuide.
Wow, that is awesome! Will definitely comment back! Thanks Daniel.
Greg Hotchkiss, aka Grasshopper (my best friends actually have called me that since college)
Letter 6 – Rodent Bot Fly
Subject: Insect ID
Location: Odessa, Florida
June 30, 2015 5:21 pm
Dear Bugman, This morning in my front yard, attached to one of my Iris leaves was this really cool insect that I’ve never seen before. At first I thought it was a bumble bee but realized it wasn’t when I got a closer look.
It has characteristics of a fly but also a bee. I hope someone can identify it! I’d love to know what it is. Thank you for your time and effort.
Signature: Brenda Wickham
You have encountered some species of Rodent Bot Fly in the genus Cuterebra. We believe it is one of the fontinella group identified on BugGuide, which includes the Squirrel Bot Fly, Cuterebra emasculator, and the Mouse Bot Fly, Cuterebra fontinella.
According to Featured Creatures, the Tree Squirrel Bot Fly: “is an obligate parasite of tree squirrels and chipmunks throughout most of eastern North America. The adult and other life stages are seldom seen; instead, what is usually observed from July through September or October is the outcome of infestation, namely the relatively large, fluid-draining swellings (â€˜warbles’) in a host’s hide caused by the subcutaneous larvae.”
We are going to copy Jeff Boettner to see if he can provide any additional information as he has assisted us in Bot Fly species identifications in the past.
Jeff Boettner responds
Hi Daniel (and please forward to Brenda),
Whatsthatbug is a good name for this one. This is a bit of a mystery. First off, this is a very freshly emerged bot…likely it had not flown yet and was still developing its color patterns and “hardening up”.
That said, this one keys nicely to Cuterebra fontinella grisea which would be great except C. grisea is a northern bot (Canada south to NJ!) and not known from FL??? But the status of grisea is kind of still a confused mess. The general host for these guys is deer mice, P. maniculatus in the north.
It is possible there is a very similar bot that is still unknown from FL in Peromyscus gossypinus? I would love to see the dna of bots found in this species of mouse in FL. So not sure what to call this for sure –but you are correct that it is likely a mouse bot in the Cuterebra fontinella group. Absolutely, a fabulous find and could be something very much unknown…Thanks for letting me know about it.
Thanks for the information Jeff and we will pass it on to Brenda.
Thank you both so much for your help and information! Very informative and interesting! I have not seen this bug again since that morning unfortunately. I have two other pictures of it that I’ll email to you. I tried sending all three pictures initially but they wouldn’t go through.
Additional images would be nice. You should be able to attach to the reply instead of sending a new form.
Good Morning gentlemen, Here are the two additional pictures of the Bot Fly. I’d love to hear about any additional information you may discover regarding this particular species. We have a very large squirrel population here, so that would be my guess as to the host.
We will await any new information from Jeff, but the head on view might be helpful.
Wow Brenda! and Daniel,
This is a female fly by the space between the eyes. It is also almost for sure a mouse bot and not a squirrel or rabbit bot without going into details and for sure . It is nearly identical to Cuterebra fontinella grisea (which will likely become two species judging by dna).
But this one is just enough different in looks (and way out of the known host range for grisea which should be north of NJ and nowhere near FL) that I really don’t know what to call it??? This could be a new subspecies of fontinella bot or possibly a new species?
I would love to try and get down that way in August to look for larvae and figure out the host? Not sure if I could get there this year…but will think about it. Its a really neat find. So glad you got multiple views of it. It is something very close to C. f. grisea, so likely using a southern Peromyscus mouse. I will start studying up on FL mice…
Very cool find. Very exciting find!
We are really excited to be able to post this unique find and to have such excellent, expert perspective.
Update: July 14, 2015
I’m so glad the additional images were helpful! This is exciting!! We’ve been at this home for 6 years now and I’ve never actually seen any mice but plenty of squirrels, so that is surprising. Please let me know if you do get a chance to visit this area.
I’d be glad to have you stop by and look around! Do you think it’s possible that I would ever see this bot again or is it usually just a onetime event? If there was any chance of spotting it again, my husband was curious as to whether I should attempt to capture it?
Letter 7 – Rodent Bot Fly
Subject: Please indentify if able, Thank You
Location: Midwest, Minnesota. United States Of America
July 17, 2015 6:36 am
Sitting, right outside my backdoor. Enjoying a morning smoke before breakfast. This little guy, decides to walk across the tows of my shoe. Down onto a leaf in the grass.
Kind of resembles a bumble bee. Only white and black. Instead of yellow, and the eyes shaped different. Which leads to my curiosity, if it may be a different species possibly.
Signature: By the person/ individual who is willing to kindly help answer my question 😉
This is a Rodent Bot Fly in the genus Cuterebra, and members of the genus are often very host specific. Rodent Bot Flies are external parasites on mice, squirrels and rabbits.
Letter 8 – Rodent Bot Fly
Subject: Large fly and spider
Location: New Hampshire
November 14, 2015 7:35 pm
I was camping in New Hampshire in the white mountains area. These two cuties were with us. One as a dinner guest and the other after a rain storm. Please help. I’m good at identifying most bugs (I actually wanted to be an entomologist ) but I was surprised by them.
Signature: Eric Barbasso
Your spider is one of the Orbweavers, and your large fly is a Rodent Bot Fly in the genus Cuterebra. According to BugGuide: “Females typically deposit eggs in the burrows and “runs” of rodent or rabbit hosts. A warm body passing by the eggs causes them to hatch almost instantly and the larvae glom onto the host.
The larvae are subcutaneous (under the skin) parasites of the host. Their presence is easily detected as a tumor-like bulge, often in the throat or neck or flanks of the host. The larvae breathe by everting the anal spiracles out a hole (so they are oriented head-down inside the host).
They feed on the flesh of the host, but only rarely does the host die as a result.” We believe your Bot Fly is Cuterebra fontinella fontinella, and according to Bugguide: “White-footed mice (Peromyscus leucopus) are the main host for this subspecies.”
Thanks for getting back to me. That’s what I thought as far the spider was concered. But, to know we have Bot Flys here is scary.
Hi again Eric,
Though sightings of adult Rodent Bot Flies are not that frequent, based on the number of rodents with bots, they are not rare, and they are no cause for alarm. The bots are not especially detrimental to the rodents and the Bot Flies do not trouble humans.
Letter 9 – Rodent Bot Fly
Subject: Unknown bug
July 15, 2016 5:15 pm
Wondering what this bug is… Found it in the grass. It looks sort of like a bumblebee but it only looks to have one wing on the back.
Dear S. G.
Many folks mistake Rodent Bot Flies for Bumble Bees.
Letter 10 – Yellowjacket preys upon Bot Fly
Subject: Hornet eating strange bug
Geographic location of the bug: Portland, Oregon
Time: 05:27 PM EDT
I was curious what bug is being eaten, I’ve never seen one before.
How you want your letter signed: Heather lux
The prey in your image is a Rodent Bot Fly, and the predator appears to be a Yellowjacket, a close relative of Hornets. Adult Yellowjackets prey upon various insects, especially caterpillars, to feed to larvae that are developing in the paper nest they build.