Bot Flies, aka Torsalo or Dermatobia hominis


Bot flies (Order Diptera, Family Cuterebridae) are large, stout bodied, hairy flies that resemble bumblebees. The botfly egg is deposited by a mosquito or sometimes by another insect. The larva grows in the host's body until it is fairly large. The botfly larva can easily be killed by taking away its air supply -- by putting vaseline or similar on the skin where the lump is, but then you still have to extract the larva. Adult botflies have nonfunctional mouthparts and do not feed. Larvae of this species parasitize wild and domestic rabbits. Females deposit their eggs in or near the entrance of their host's burrow. Bot fly larvae penetrate their host through the skin or natural body openings after hatching. The larvae form a tumor (called a warble) in the subdermal zones of their host and remain at this location until larval development is complete. Larval development varies among species, ranging from 20 to 60 days. Before pupating, the larvae leave the host's skin and drop to the soil.

Generally, the host is not severely damaged by this parasite. The majority of the injury occurs when the larvae exit the host through the warble. Parasitism by the botfly does not affect the edibility of the rabbit (assuming you eat rabbit), generally the area adjacent to the warble is trimmed away, and the rest of the rabbit is suitable to eat.

Is there such a thing as a human bot fly? Yes, we're sorry to say there is. Called the torsalo, Dermatobia hominis, occurs in Mexico and Central America. Fortunately, getting one is an extremely unlikely occurrence for the average visitor.

torsalo_instar2.gif - 25.9 K
2nd instar torsalo larva, note the hooks to hold it in place!

One of the really cool things about this insect is that it lays its eggs on a mosquito and the eggs hatch when the mosquito feeds on a host. Do humans get warbles? Yes, (are you disgusted yet)?

torsalo_warble1.gif - 33.7 K
A torsalo warble

While the maggot feeds on its host (you) it has to have a hole in the skin so it can continue to breath. It takes about 6 weeks to complete development on its host. There are stories of entomologists rearing torsalos on themselves in order to get a good specimen of an adult (which are rarely captured), but we regard this as taking your profession a little too far.

Camphorated snake oil -- a product of Mr. Peter Singfield of Xaibe Village, is an excellent solution. Also good is his highly camphorated virgin coconut oil.

Says Peter:

Just take a little tobacco -- or even heavily camphorated oil soaked in a small cotton packing -- tape over vent hole -- the worm comes out -- 8 hours later pull off the tape -- voila -- one grub -- no infection -- everything OK.

I tell people here to apply "Tiger Balm" to every "bite" -- as soon as they know it.

Tiger Balm is rich in camphor.

Ivermectin will kill the beef worm/botfly. Just a dab on a Q-tip is enough. ( Ivermectin is what you use to control heartworm in your dog )

If you treat when the worm is still small, your body will resorb it. If it has developed, it will die and you can squeeze it out in a day or so after its spines have relaxed.

With Batlass bites, I am not usually stationary long enough for them to bite me much. . . .But when I do get bitten, I sometimes try to squeeze or scrape out some of the blood, when I get home . . Then usually put Alcohol on them, any alcohol will usually do, such as mouth wash or any other, peroxide is usually further away.. . . . . I don't know the chances of Botfly. . . .I have probably spent over 100 hours in various parts of the bush and jungle, and so far not been caught by one of those, I don't usually wear a hat either. . . .Also avoided problems from Doctor flies, they can be fast, but so far, never really hit me hard. Infection is not usually a big problem with bot fly larvae. If there is, use some antibiotic ointment - a little dab will do ya.

With the phlebotomine (batlass) fly bites, if you pop the little blood blisters the itch is measured in hours. If you don't, the itch is measured in days. Get rid of the toxin as soon as possible. Some just don't get bothered. One girl with us had no problem. The rest of us were itchy hamburger!

You know -- here -- in every village -- they have one or two people that are very good at squeezing them out botflies. Not just for people -- but for dogs to -- which get a lot of these.

They have to feel first -- to line up the grub properly -- then they squeeze in a special way -- a real "art" -- and the worm just pops out -- shooting ten feet or more -- like from a gun.

From what I have observed --

It is like they are massaging the worm -- very gently -- then "pow" -- a sudden fast squeeze -- just the right pressure -- and at just the right time.

As for myself -- I am probably getting a few of these each year -- but never know it. Applying camphorated oil all the time to every bite. Remember how I carry it around with me in the car??

Anyway -- it probably kills and expels the "seed" -- so nothing gets to develop. Camphor is a very powerful "penetration" agent. Oil has always been good stuff for wounds -- etc.

By the way -- here is the "original" Vic's Vapour rub -- using coconut oil --

Heat four teaspoons of coconut oil. Crush one teaspoon of camphor (Kapoor or Karpura). Dissolve this in the oil. Keep it stored in airtight bottles. This can be rubbed on the chest and throat of the child to relieve congestion. (This can also be used for any muscular pain).

From this site:

Whole bunch of home remedies from India there --

Now -- check out this site for old American home remedies -- lot's of good stuff there -- and lots using camphor -- hey -- this is where Vic's comes from!!

Here are a few folks' experiences with botflies in Central America:

You can normally tell if its a bot fly from the breathing hole in the skin that the bot fly needs in order to be able to breathe.

It is typically a very clean pin head hole, I used to do a few extractions of Bot flys from the British military when they came out to the island from the jungle, they had all kinds of pretty gross things from being stuck in the Jungle day and night for weeks on end.

Anyway to get the bot larvae out alive we used to take a Coke bottle and light a cigarette take a few puffs of the cig and blow the smoke into the bottle, once the bottle was full we would hold it over the breathing hole and wait for the larvae to come to the surface of the hole in order to get some fresh air, once it poked its head out we would get the squaddie up against the wall and 2 to 3 of us would put our thumbs around the perimeter of the hole and push as hard as we could.

I tell you we had to push hard but eventually this big hairy maggot came out pretty disgusting.

Once it was out we put it in a clear film canister for the Limey to take with him, disinfected the area and he went on his way.

I only noticed a slight swelling and redness around the hole.

My husband had a botfly bite him at Chan Chich a year ago. He had a bump on his head that kept growing and was painful. No other symptoms. He finally went to his MD who referred him to a plastic surgeon. She took it out on the spot and it bounced off the table and on the floor causing the medical assistant to shriek in fear. Surgeon sent it to a lab and a lab tech who had been to the tropics recognized and identified it as a botfly. It grows larvae inside the bite spot and eventually, they come out. If you type in "botfly" on the net you will see some gruesome photos.

We learned that this is fairly common and the locals treat it by using a lighted cigarette over the wound, drawing the larvae out. Everybody on the bz culture list laughed when they learned that my husband went to a plsstic surgeon!

But the swelling and puffiness in places other than the bite site concern me. Its possible that this is an allergic reaction atypical of a botfly, but my recommendation is that your wife go to a plastic surgeon and have the bump opened and whatever is inside removed and analyzed.

When my husband got the lump and it kept growing, my big fear was, not surprisingly, cancer (as is always a concern when you have a lump). The botfly scenario was actually a relief. Nobody ever died from a botfly bite.

By the way, from what I have heard, its not very common to have these bites on AC, most often they happen in the jungle.

From the Message Board:

We just returned from a great trip and my wife has a bite on her head that is not going away. She has severe pain (the Dr has given pain killers and anti-biotics and says it may be a spider bite, but he doesn't really know). She managed to convince the Dr to get some tests done (primarily for Chagas, because that one could be serious), but won't hear the results back for some time. My wife's face is now puffy/swollen down one side and she has periods of nausea. She was bitten about 15 days ago. The sore is now 1/4 of an inch wide and oozy. The area immediately surrounding the bite is perhaps an inch wide and very swollen. Her face is more puffy than 'swollen'. This makes it all sound worse than it is, but the real problem is not knowing what she has. I would be grateful if anyone could drop me a line if they could let me know their symptoms.

We were actually in the jungle near San Ignacio for 5 days before our arrival in AC....

Many Thanks

There are a few responses from folks, some of which are already on this page...

Then Mike goes on to say:

Thanks all. Your concern has been greatly appreciated by my wife and I. We went back to the Dr's this morning, clutching a medical report on Botflys. We pursuaded him to open up the wound. He found a 6mm long larva. The picture of it is to the right.

My wife is totally relieved now (although a little traumatized). The Dr is sending the larva off for positive identification. He doesn't anticipate and further complications.

It certainly seemed that she was reacting to the larva. Her lymph glands were going up and down since the bite. Apparently the swelling was very pronounced because it was on her head. If it had been on her back, leg or arm, it would have appeared much smaller because the swelling would have been absorbed by the muscle. On her head, there was nowhere for the swelling to go but up and out.

The pain was also severe because of the presence of a lot of pain receptors, nerves and blood flow in the scalp, compared to, say, a person's back. That is probably also why her face swelled up as well.

We are both just relieved! Fortunately it hasn't dented my wife's enthusiasm for travel, hopefully we're off to Thailand next year!

Many Thanks

A couple of days later....
This is almost too much...two days after the removal of the first larva. We've just found a second, in the same place as the first. It looks like we've got twins.

We are currently trying to remove it using a thick layer of vaseline. The larva is supposed to move in to the vaseline to try to get to the surface. We can grab it as it emerges....I am not convinced and Louise (my wife) is not happy....

Another day later....
It worked! After 6 hours and several missed attempts we got it! This larva was much bigger than the one removed on Thursday, almost 1/2 inch long and 1/4 of an inch thick.

We had to do it at home because we'd had quite a heavy snow fall and the doctor's is 45 minutes drive away. He said he would try the same, rather than the surgery again.

If anyone has to do this, the way to grab the larva is to place a very thick layer of vaseline (over 1/2 an inch) and wait (in our case 1.5 hours between each attempt to grab the larva). Earlier attempts missed because the larva retracted into the hole on my wife's head too quickly. Wait until the larva is a long way out of the hole and then go for the base really quickly and tug the larva out in one movement.

We finally wrestled it free AND intact at 8pm last night. Now we're just waiting to see if there are any more....clear so far today, so hopefully that will be it.

If the bites have 1-2mm holes on top of the bites 13-17 days after they were bitten, then I suspect you have what my wife has/d....


Are humans parasitized by bot flies other than the torsalo? The answer, sadly, is yes. Most (all) of these are accidental infestations, but the consequences can be severe. The most dangerous I'm aware of are some of the nasal bot flies. The adults lay live larvae (larviposite) and actually fling larvae up the nostrils of the host (typically sheep). These nasal bots can really do a number eating away at the sinuses and associated infections can be fatal. However, this is an extremely rare occurrence in humans. There is a list of other bot flies that have been recovered from humans, but again most of these are accidental. I believe the human bot fly is the only regular cause of myiasis (feeding on living flesh by fly larvae) in humans. A medical entomology reference (Entomology and Human Health 1979, Harwood and James) lists only 8 reports of rabbit bots on humans through 1972.

While viewing the very active volcano Arenal in the small town of La Fortuna in Costa Rica a fellow named Mark was bitten by a mosquito. This happened on November 24th, 2000 at night in the viewing area of Los Lagos. The following was written by his wife....

Upon returning home from Costa Rica Mark started experience a strange pain in his scrotum. He finally mentioned it to me (his wife) & we talked about what it could be. Spider bite? Infected mosquito bite? Then I remember reading something in the guide book from our 1st (honeymoon) trip about a weird bug in Costa Rica. The guide book Explore Costa Rica by Harry S. Pariser said.... "Botfly (Dermatobia hominis), whose larvae mature inside flesh. An egg-laden female botfly captures a night-flying female mosquito and glues her eggs on to it. When the mosquito is released and bites a victim, the host's body heat triggers an egg to hatch. It falls off and burrows in. The larva secures itself with two anal hooks, secreting an antibiotic into its burrow, which staves off competing bacteria and fungi. Its spiracle pokes out of the tiny hole, and a small mound forms which will grow to the size of a goose egg before the mature larva falls out. Should you be unfortunate enough to fall prey to a larva - an extremely unlikely occurrence for the average visitor - you have three cures available. One is to use the acrid white sap of the matatorsalo (bot killer), which kills the larva but leaves its corpse intact. Another is to apply a piece of soft, raw meat to the top of the airhole. As the maggot must breath, it burrows upward into the meat. A third is to apply a generous helping of Elmer's glue or cement to the hole. Coating the skin surface with vaseline also will force the lil buggers out. Cover this with a circular patch of adhesive tape; seal this tape with a final application of glue. Squeeze out the dead larva the next morning. The only other alternative is to leave it to grow to maturity, giving you an opportunity to experience the transmogrification of part of yourself into another creature. It only hurts when the maggot squirms and if you swim, presumably because you are cutting off its air supply. Don't try to pull it out because it will burst. Part of its body will remain inside and cause an infection." Thank you for adding that bit to your guide book Harry. (If we had not read that I am not sure what would have happened to Mark). Harry S. Pariser is the author of Explore Costa Rica & Explore Belize

I had even highlighted this information & remembered telling Mark" listen to this". Well since we are not the average visitor I knew this had to be what was bothering Mark. We tried the raw meat but guess the botfly didn't like the cut of meat Mark used as it didn't work.

The pain was not like the book described, Mark was getting bitten at random times. Mostly when he tried to sleep & different times at work. Since he is a great bearer of pain he decided to call UTMB to see if anyone there wanted to do a case study on this rare occurrence. He was told to email the "WHO Collaborating Center for Tropical Diseases". He did so giving full detail as to what happened, meanwhile I made him a Drs appointment with our general Doc. This Doctor decided that Mark must have lice & gave him lice medicine. Meanwhile the botfly's got bigger & the biting worse. Customers even noticed it & said something to me. How do you explain?

Mind you all this was going on during the Xmas season & the computer store was busier than ever. We were working on a Sunday (Dec. 17th, 2000) afternoon trying to get caught up when Mark went down on his knees in pain. It scared Cole & I so bad that I knew we had to get rid of these things somehow. I talked Mark into going to the emergency room where upon explaining to the attendant what was going on a young guy sitting beside her said "I have heard of botfly's before"! We both asked him what he knew & where he had heard about botflys from. He told us that he heard about them on the Discovery Channel but didn't know much. Wish he had been a doctor!

Going to the emergency room I watched at the door as Mark laid on the examining table totally depressed. One lady Doc picked up Marks chart & said "I'm not touching that!" Hours later a Doc arrives & we tell him the story. He asked us "What other DR's are you seeing & are you on any kind of medication"? He then tells us he has to call in a urologist.  Meanwhile he goes to a computer & types in "botfly" I sneak up behind him & say......there is a lot more information on the net if you want me to show you where it is at! He turned to me in surprise & say's "no, the urologist is on his way from home". Enters Dr. Michael Rashid, MD Resident of Urology. He believes us but is skeptical. We sets up an appointment for the following Tue. AM. Meanwhile Mark is still experiencing terrible pain till the day of the appointment Dec 19th, 2000.

Dr. Gabriel Rodriguez, MD & Assistant Professor of Urology examines Mark & asked him to sign a consent form for photos. Off we go to the operating room where normally vasectomies are performed. I was allowed to be with Mark during the operation. After he was prepped (shaved & cleaned) they took photos of the sores. I didn't realize there were two spots. Dr. Rodriguez starts cutting, then tells Mark he has to go deeper into the tissue. Mark said he could see the surprised look on the Doc's face when he exclaims "It's alive"! He tells the attending nurse to get a container & drops the botfly larva into it. The nurse is checking it out when Mark tells him "I read on the internet that those things can jump 6 feet". He slams the lid on the container & sets it down! I pick it up & take it over to Mark. We watch this thing squirming as they close up the area it came out of & get ready for botfly  #2! This one is also alive & all we can think about is the movie Alien.

botflyla.jpg (9596 bytes)

This is a photo of the actual botfly larva removed from Mark.
Nasty looking critter isn't it?

botflyho.jpg (8889 bytes)

botflymo.jpg (8869 bytes)

This is a close up of the spines.

This is a photo of it's mouth.

The photos were taken by Stephen Higgs, Ph.D.
with the Department of Pathology at UTMB.

When Mark came back to the office (yes, he came straight to work) after the surgery he had a email from the WHO Collaborating Center for Tropical Diseases. It said "his email was read by a professor experienced in this area at UTMB & he suggested Mark visit any competent dermatologist for appropriate evaluation and management. In addition, from your (Mark's) email there is no indication that research is required or that the problem is necessarily botfly-related."

Boy was Mark mad. He emailed them back letting them know what he had just been through & ended it with........."The only Botfly larva survivor you will ever know!"

One day Mark commented on how uncomfortable the stitches were. I told him "well now you have a little knowledge of  what child birth is like". His reply was "Yes, but I had twins!"

Mark has healed & is now doing fine. We have been the joke of customers & friends that have heard about the incident. We even had a special poem written to the version of "Twas the Night Before Christmas." Written by Bryan Springer.

The Mark Johnstone Version of "Twas the Night Before Christmas"

"Twas the week before Christmas, and boy was it neat.
We had been on vacation, and my wife was in heat.
The doors were all bolted, the phone off the hook,
It was time for some nooky, by hook or by crook.
Momma in her teddy and I in the nude,
Had just hit the bedroom and reached for the lube.
When out from my privates there arose such a cry,
That I lost my boner and thought I would die.
Up to the window I sprang like a very big flea,
The pain was so bad it stung like a bee.
I ran down the hall past the 'putter I'd built,
And looked in a mirror, clean up to the hilt.
When what to my wondering eyes should appear,
But an airhole in my scrotum - I said to her....Dear.
With two holes now seen, half out of my sock,
It's time for a phone call, right now to a Doc.
The first one I called, said I'd just lost my mind.
So I paid him his worth ... it was only a dime.
The next one I called said it was just a small mite
Sure as I'm speaking, he was high as a kite
All I had left was to lay there in pain
A cry in the night with nothing to gain
Then down the chimney came a big red guy
St. Nick I told him, it must be a fly.
He was chubby and plump, a right jolly old prick,
And I laughed when I saw him, in spite of my dick.
A wink of his eye and a twist of his head
Soon gave me to know I had more problems to dread
Whoa Shithead he said - you are such a Putz,
Stop whining right now or I'll cut off your nuts.
A phone number he gave and a big bag of ice
He said call this Doc and he will be nice
He sprang up the chimney, to his team gave a whistle
And away they all flew like the down of a thistle.
But I heard him exclaim boy "Don't bitch or don't pout"
"Merry Christmas to all and be glad they are all out!"

The articles below were given to us by Dr. Rodriguez when Mark went in for his check-up.
Thank you Dr. Rodriguez & Dr. Rashid!



Michael Rashid, MD
Resident of Urology
The University of Texas Medical Branch at Galveston

Gabriel Rodriguez, MD
Assistant Professor of Urology
The University of Texas Medical Branch at Galveston

Cutaneous infestation by Bot Fly larvae, Dermatobia hominis, is endemic to tropical regions of Central and South America which typically victimizes small rodents and livestock. Because human myiasis is exceedingly rare even in endemic areas, correct diagnosis outside the endemic area is difficult because of unfamiliarity with the disease. Lesions produced by this insect are easily mistaken for cutaneous furunculosis. Though the disease is self-limited it commonly causes significant pain to it's victims. In humans,  early correct identification would avoid unnecessary treatment with antibiotics and allow earlier removal of larvae. To our knowledge, we present only the second case of scrotal myiasis caused by Dermatobia hominis in literature to date. The larvae were excised under local anesthesia with excellent results.

Case History:

48 Y/O WM presented to the urology clinic with complaints of "Pain in my scrotum". He describe the pain as intermittent, intense, and abrupt scrotal pain which began after recent travel to Costa Rica. He and his family had traveled to Costa Rica in late November to observe the Volcano Arenal eruption from the Los Lagos observatory. At night, while he was changing his clothes he felt a "mosquito" bite on his scrotum. He complained of immediate scrotal pain, which resolved quickly and without any signs of skin trauma.

Upon returning home he began noticing two"lumps" in his scrotal skin which would cause intermittent episodes of intense sharp shooting pain throughout his scrotum and perineum. Nearly four weeks from the initial bite, he noticed that these two tiny lesions on his scrotum had "bloody discharge" but no signs of infection.

Two other physicians told him that his symptoms were related to a skin infection. He was placed on oral antibiotics for a presumed scrotal cellulitis and told to follow up in the urology clinic.

His scrotal exam was significant for two distinct furuncular lesions with a central pore. One located mid-raphae and the second on the right hemiscrotum. No fluctuance, however bloody discharge could easily be expressed with gentle pressure. The lesions measured approximately 1.5cm x 1.0cm

The patient had both lesions surgically excised revealing two live Human Botfly larvae. Pathology demonstrated infestation with fly larva (Myiasis) with inflammation, identified as Dermatobia Hominis.


Diagnosis of edemic tropical disease can prove difficult to physicians in other parts of the world. In this case of myiasis (parasitism by insect larvae), the patient developed painful lesions of the scrotum which were thought to be furuncles by other physicians.

In order Diptera family Cuterebridae, there are a number of fly species which utilize living mammals to incubate larvae. Parasitism of livestock and wildlife is common though human infestation with these species is usually accidental. However, one species does specifically target humans. Commonly known as the botfly or torsalos,

Dermatobia hominis is endemic to forest and jungle regions of Central and South America. Adult flies will capture other insects, such as mosquito's, and will lay eggs on them. These insects then act as vectors when they land on warm-blooded mammal. The larvae sense the increase in temperature and hatch. Once deposited, the larvae burrow into the subcutaneous tissue and grow for up to 6 weeks. Some species migrate through the host body to continue its growth at a separate location, but D. hominis does not migrate. At maturity, the larvae emerge, fall to the ground, and pupate into adult flies.1

Lesions produced by bot fly larvae often are mistaken for infectious lesions. 2,3,4 The initial penetration is usually painless and unnoticed by the patient. Infestation with multiple larvae is common. As the larvae grow, a subcutaneous mass becomes evident and the lesions are puritic. A pore, called a punctum, is present in the center of mass. The punctum is used for ventilation and excretion of waste. Seroganguinous fluid can be expressed and sudden paroxysmal episodes of sharp sever pain are usual. 3 On physical exam, the lesions seem to be non-tender. Without treatment, larvae emerge and lesions heal with good cosmetic result, however patients must endure painful episodes for up to 8 weeks.

Treatment involves removal of the entire larvae and may be achieved with several different methods described in the literature. Traditional tribal treatments include applying thick tree sap, raw meat, or animal fat to occlude the punctum and force the larvae out in search of air. This method of using occlusive dressings in combination with manual extraction has been described in the literature with success.4 However, attempts to extract larvae with traction run the risk of leaving fragments behind. Warm compresses or injecting lidocaine under the larvae also have been reported to force the parasites to the surface.3

Lesions in this case involved the scrotum. The patient attempted to lure the insects out by suffocation without success. Because of its redundancy, scrotal skin lesions are particularly amenable to surgical excision with good cosmetic result. Surgical excision of scrotal infestation may therefore be the treatment of choice.


  1. Harwood RF and James MT. Entomology in Human and Animal Health. Macmillan Publishing.      1979.
  2. Bowry R and Cottingham RL. Use of ultrasound to aid management of late presentation of Dermatobia hominis larva infestation. Journal of Accident and Emergency Medicine. 1997; 14:177-78.
  3. Johnston M and Dickinson G. An unexpected surprise in a common boil. Journal of Emergency Medicine. 1996; 14:179-781
  4. Infectious Disease Pathology Conference
    February 14, 2001
    Case #1 (SP-00-17770)
    Laura Chandler, Ph.D (Clinical Microbiology)
    Gabriel Rodriguez, M.D. (Urologic Surgery)
  5. Gewirtzman A and Rabinovitz H. Botfly infestation (myiasis masquerading and furunculosis. Cutis. 1999; 63:71-72

Clinical Summary: This 48-year old male reported to UTMB with two painful lesions on the scrotum. He has no significant past medical history, but reported recent travel to Costa Rica. The lesions were examined and surgically removed.

Diagnosis: Myiasis due to infestation of the skin with Dermatobia hominis (human bot-fly).

Description: Myiasis is an invasion of tissues or organs by larval forms of insects in the order Diptera (true, two-winged flies). This order contains several families of medically important flies, including Sarcphagidae and Calliphoridae (screwworms and blow flies), Oestridae, Gasterophiliadae (botflies). Dermatobia hominis is in the family Cuterebridae and is referred to as the human botfly. The adult flies are 12-19 mm in size, with a yellowish head, dull blue-black thorax, and metallic looking abdomen. The legs are orange, and the wings are brown. This species readily infests several other species besides humans, including wild or domestic mammals, and birds. Infections in cattle and sheep can have significant economic effects

The life cycle of the botfly Dermatobia hominis is quite interesting because of the way in which the hosts become infected. Female flies do not deposit their eggs directly on the host. Rather , the adult female fly (after mating), actively seeks out biting arthropods such as ticks, mosquitoes , or other species of biting flies. The botfly captures the other arthropod, hold it's wings to prevent escape, and then attaches her eggs (roughly 15-30 at a time) on the abdomen of this other insect. The biting insect then carries around the botfly eggs. When this insect finds a suitable host for its own blood feeding, the botfly eggs are stimulated to hatch by the warmth of the host. A first-stage larva emerges from the egg and is deposited on the skin. The larva will burrow into the skin, either directly through intact skin, or through the bite from the insect vector. It can also enter through hair follicles or damaged areas. The burrowing process takes 5-60 minutes but apparently is not usually noticeable to the host.

The larva will develop at the site of entry, it does not migrate through the body although it does move around under the skin. It's anterior end is found towards the inside, and the posterior end is located at the skin surface. The anterior end is used to grasp host tissues for feeding. There are two oral hooks which are used for tearing tissue during the feeding process. The curved spines along the body assist with anchoring the larva in the skin. The larva is able to breathe through small spiracles located at it's posterior end, where the skin will remain open. The pattern of spiracles is one of the features used to differentiate the various species of botfly. The developmental stages take 4-14 weeks. The larva goes through two molts, to a 3rd instar stage, with emerges from the skin and drops to the ground. It pupates in the ground, taking 14-30 days to mature to an adult, which then emerges. Adult botflies do not feed, and live only a short time. The females are able to develop eggs because of the stored resources acquired from the host during larval development. Botflies are obligate parasites of vertebrates: their larvae must undergo development inside a warm-blooded host.

Epidemiology and Ecology: The distribution of Dermatobia hominis botfly includes Mexico, Central and South America. In the U.S., cases usually occur in travelers who have visited endemic areas. Flies live near water, thus coastal and forested or jungle areas are endemic for this species.

Clinical Manifestations: May depend on the location of the fly larva on the host's body. Usually larvae are found on the arms, legs, back and scalp. Other areas that have been reported are brain, eyelids, tongue, nose, genitalia and buttocks. Approximately 24 hours after infestation, a small (2-3 mm) papule will develop that resembles an insect bite. This will enlarge gradually to 10-35 mm and will be approximately 5-10 mm in height and will be surrounded by an area of induration. A breathing hole will be visible in the center of the lesion. As the larva develops, the lesions may become pruritic and produce a discharge that may be serous, serosanguineous or purulent. A secondary bacterial infection is actually uncommon. Often, pain (a stabbing feeling) is felt by the host; this is a result of the larva tearing off tissues while feeding, and from the spines irritating the tissues as the larva moves around. Usually systemic signs and symptoms do not occur, but occasionally malaise, letharge and insomnia have been reported.

Pathology: Moderate inflammation may occur in the area where the larva is found in the subcutaneous tissues. In general, secondary bacterial infections do not occur.

Diagnosis: Definitive diagnosis is made by removal of the larva followed by indenification by a medical entomologist or trained personnel. Tentative diagnosis can be made if there is a history of recent travel to an endemic area, and presence of non-healing lesions on the skin. The lesion may resemble other infections, so presence of the larva should be confirmed. Identification of the larva is relatively easy and is made by examining the spiracles, mouth hooks and pattern of spines on the body. Dermatobia hominis is easily distinguished from other botflies found in the Western Hemisphere, such as Gasterophilus spp. A similar fly, Cordylobia anthropophaga (also called the Tumbu fly), is found in Africa. Larvae are similar to Dermatobia hominis,but can be distinguished by the spines and spiracles.

Treatment: Removal of the larva. Larvae will migrate out of the skin if their spiracular plate is covered. A number of substances have been used to accomplish this, including nail polish, tape, wax, mineral oil, etc. The larva can be removed by grasping with forceps or applying pressure on both sides, but because of the curved spines, surgical excision may be required. Antibiotic treatment is not usually necessary and should only be used if a bacterial infection has developed.


Harrisons Internal Medicine online. Chapter 393, Ectoparasite Infestations and Arthropod Bites and Stings, Myiasis.

Kettle, D.S. Medical and Veterinary Entomology, 2nd Edition. CAB International, Cambridge, U.K. 1995. Chapters 14 and 15, pages 268-314).

--Information by Tiffany Heng-Moss and Leon Higley (with stuff from the books Livestock Entomology and Entomology in Human and Animal Health)

Botfly, Don't bother meeeee......

We too visited Arenal in CR this June. Upon return, my 8 year old daughter kept complaining about shooting pains periodically coming from two "mosquito bites" on her head. The pediatrician confidently diagnosed it as impetigo and put her on anti-biotics. After 10 days and no results - stronger AB's. After 4 days and no results - off to the dermatologist. Dr. Skin can't figure it out so she decides to do a biopsy. Much to her surprise - it's a maggot!. Congratulations! you have given birth to twin 5 week old botfly larvae! The dermatologists office thought this was the coolest thing since alligator shoes. Found your story on the net after scraping Mom up off the floor. Thanks for sharing your experience! It does make for good gross-out story telling...

Bryan Edwards
Mandeville, Louisiana

Wow, that's quite a story...I must say, I never thought I would hear one better than mine, but you win. Congradulations :) I just feel compelled to share my story with you because, if anyone else, you'll be able to sympathize.

I went to Belize this summer with my father for a scuba trip. We dove every day except for one: the last day, where we went and hiked through the Mayan jungle and then went cave tubing. While in the jungle, I happened to get a couple of mosquito bites on my leg, which I thought nothing of. Two weeks after arriving back home, they were still there, itchy and painful as ever, so I went to the doctor. I had previously heard something about botflies, but didn't really think it was possible. So when I went in to see the doctor, he told me it was just an infected mosquito bite, nothing more. After I told him what I knew about botflies (although I didn't know the name at the time), he decided that they would lance the largest one and drain it (because, according to him, I was overreacting). No more than two minutes after they had opened the bite, they pulled out a little wriggling botfly. Now, of course, they had no idea what it was, so both the doctor and the physicians assistant flipped out and called the then they opened the second bite, but didn't find anything. After all that, they glued my leg back together and gave me some medicine.

A month later, the second bite they had opened wasn't healing at all (the first one healed and there's barely a scar), so I went back to the doctor. They opened it up again, this time digging all the way down to the muscle, and still didn't find anything. They sewed my leg up again, gave me more drugs, and sent me on my way. A week later, I came back to have my stitches removed, and it still wasn't healed, so he began talking about simply removing all of the tissue that next week. Two days after that appointment, I was looking at the wound and it appeared to be moving! I thought I was going crazy, and I showed it to a lady at work who used to be a nurse. She told me it was probably just pus trying to work its way out, so I shouldn't worry. Later that day, I would push on it a bit and this big long white thing would come out of it.

Now, by this time, I was getting pretty sick of having bugs in my leg, so I called the doctor immediately and told him what was up....he made me come in that afternoon. I showed him the thing and he said "Its a maggot, we have to get that out of there". So they pulled out this 1.5 inch botfly maggot, and sent me home. The very next day, I bent down to pull off my bandaid, when another maggot fell off on my hand. I called my neighbor, who is a plastic surgeon, and he came over to look at it. After inspecting it, he decided we needed to go to the emergency room and take out all of the tissue in the area. So now, because of a great trip to Belize, I'm left with 2 very purple scars on my leg :) I'm just glad to know that I'm not the only freak this happens to!


I want to thank you for placing your account with the bot fly infestation on the internet. My husband and I traveled in late September-early October to Belize. Not too long after our return, I noticed a lump on the top of his head and asked him if he had hit his head or something. He teased me for my violent ways, said it was probably a pulled hair, and said it would go away. Well, it didn't and it was sore and oozing fluid. Like any good wife, I demanded that he see a doctor before I became a widow (I was irrationally thinking it was some form of cancer at that point). The first doctor thinks nothing of it, gives him some antibiotic ointment and pills and sends him on his way. When that doesn't change anything in 3 days, I hit the roof and told him he had to get a second opinion or resolve himself to sleeping on the couch. He calls the other doctor back who suggests he see a surgeon to see if it is something that needs to be removed.

Imagine the surprise when the doctor's local surgery REMOVES A WHOLE OBJECT from his head. The doctor was so surprised he almost dropped the thing. It was nothing he had ever seen and, after cutting it open to look inside, he sends it off to a lab.

Imagine OUR surprise when the doctor calls today saying it was some kind of fly infestation. The ONLY reason we know it's a bot fly larvae is because we typed in "fly lays egg under skin" into the Google search engine. Warbles? Bot flies?! Damn bot fly pictures look just like the one that came from his head.

My husband has called the doctor back with the identifying information. Thanks for sharing your story and listening to mine!


Hi there,

Thank you so much for your thorough review of the Bot Fly.

I am a family physician in Bellingham WA. I work at an Urgent Care Center. Today I saw a 24 year old male who had traveled to Costa Rica 3 weeks ago.

He remembered being bit by a mosquito on the left calf one night while sitting on the beach. Two sites became itchy and eventually each formed indurated papules with a 1mm umbilicated center. The persistence of the lesions combined with their waxing and waning pain and itching motivated him to come see me.

Admittedly I wasn't sure what was going on. Two days ago I treated him with an antibiotic figuring these were boils. But today the patient said it felt like something was moving. One thing lead to another and I cleaned and numbed up his leg and got the larva out of one site.

I didn't know what it was but I knew that I had seen it before. After exhausting all the texts where I thought I had seen this, I went to the internet. A search on "subcutaneous larva costa rica" led me to your site.

What a resource!

I have forwarded the link to the patient.

He is excited to have the information.

I did not attend to the second site today. He wants to try the meat treatment tonight.

Thank you for your site.

The information has helped a very grateful, if not understandably repulsed, 24 year old male.

The information has made me look like I know what I'm doing (always a goal in the doctor biz).

Total time from excision to diagnosis thanks to your site: around 3 hours.

I appreciate your having the "balls" to share.

This is truly a representation of the value of the internet.

Gratefully yours,

Todd Cowdery

Hi! My name is Maya Almaraz and I am a freshman at the University of California, Berkeley. In January I went on a trip to Belize as part of a research team out of UC Davis. We were trapping and tagging spinney pocket mice and other small rodents in the rainforest to study thier relation to seed dipersal and germination. I have been back for about a month and today I found out my friend and I both have beefworms (botflies). I had seen doctors twice before and was told it was an infected mosquito bite and given antibiotics. Both times I had specifically asked if it was botflies because while on our trip a man staying with us had a couple in his head and had a friend squeeze them out at the dinner table for him, that image stayed with me. So after seeing a tropical disease specialist I found I have three. They are in no way the size of a goose egg, but big enough to feel. I was told I need surgery (even though I have heard the raw meat theories) and wondering how long it was before Mark finally got his professional treatment and how urgent treatment is for me and my friend. Thanks a bunch and I hope to hear from you soon.

-Maya Almaraz

Brenda has advised her, and obviously, there is more to come on this one!

I have another botfly story to add to your collection.

I had been on vacation in Belize with my boyfriend, Arch, from February 22 to March 3, 2003. When I returned to St. John's, Newfoundland on Monday, March 3, 2003, I noticed a small bump on my left cheek, near my eye. It was slightly red and itchy and I thought it might be a mosquito bite or a zit. I had no recollection of being bitten. I carried on normally when I returned home, however, by March 9-10 the red spot was getting bigger, redder and more irritated. On Tuesday, March 11th I was driving home to lunch when I got an excruciating stabbing pain in the bump and it began to ooze a clear fluid. It was throbbing and red and swollen. I had read about the botfly in a book before I left for Belize and jokingly thought whatever the bump was was about to hatch!! It didn't hatch but I did call my family doctor and made an immediate appointment for that afternoon. When he examined my face he diagnosed it as a bite that had gotten infected and to which I had an allergic reaction. I made sure to tell him I had just returned from Belize and the length of time I had been there. He prescribed the antibiotic Cipro for me.

I took the Cipro however had an allergic reaction almost immediately. I called my family doctor the following day and he prescribed another anitbiotic, Ceftin for a period of 7 days. I began taking that but did not notice any difference in the bump on my face. On Thursday, March 14 we were having a baby shower for my sister-in law. I spent most of the night with a tissue to my face as I was assaulted with these stabbing pains and fluid continued to leak out of the bump. As the weekend came on, the bump continued to grow, it became redder, my face became swollen from my eye to my chin and the stabbing pains continued. The bump looked like a volcano - raised, round, with a hole in the center. It continued to ooze fluid that was mostly clear but sometimes a bloody brown or black. I even tried a bread poultice to try and draw out what I believed to be an infection. It didn't work.

By the week of March 17, the bump was beginning to bleed spontaneously. I would be sat at my desk at work or driving in the car and I would feel blood flowing down my face. The stabbing pains continued and became worse at night. I called the clinic I had attended for shots prior to my trip to Belize and explained the problem to them. They suggested that I consult an infectious disease specialist however I needed a referral from my family doctor. I returned to my family doctor and explained to him that I thought it might be a botfly that was causing the bump on my face - he told me I was watching too much Star Trek!! I asked him send me to an infectious disease specialist and he said he wanted to "give it another shot." He called the infectious disease specialist and explained that I had an abcess on my face. The specialist recommended some antibiotic in 500 mg tablets - two tablets, four times a day. I took the tablets for 24 hours and my face actually got worse. The swelling was so pronounced that my eyelid was drooping and felt as if it was beginning to shut. My face looked like I had had a tooth pulled. The bump was still oozing fluid of various colors spontaneously and it was still bleeding with the stabbing pain.

On the afternoon of March 19 my office assistant, Cora, came into my office and said she didn't want to scare me but she had been researching the botfly on the internet and was reading stories off your website and the symptoms being described were identical to the symptoms I had been describing. I had been pretty calm for the last 2 weeks but when I read the symptoms and saw that they were exactly what I was experienced I started to feel a little freaked out. I called my family doctor again who told me not to panic, that it took antibiotics 48 hours to work and I should wait to see what they would do. I explained how I had taken antibiotics for a week with no difference in the symptoms and since taking the new drugs, my face had actually gotten worse. He told me if I was still worried to come in at the end of the week.. At more prodding from my colleagues ( who were completely grossed out by the bump and convinced it was the botfly) I went to the emergency department of one of the city hospitals armed with the literature from your website.

At the hospital, myself and my friend Cheryl, explained to the nurse what we thought it was. To my surprise, she didn't call in a psych. consult but actually seemed to believe us. Then to our surprise, a friend of ours who is a surgeon showed up. He immediately took out a syringe to aspirate the bump to see if there was any infection and of course there wasn't any. The E.R. doctor had a look at it, squeezed it a little until I told him he could squeeze away as the bump itselt wasn't painful, just the inflamed area around it. They concluded that these two factors, no discharge or tenderness, indicated that there was no infection. We discussed the literature we had brought with us, the doctors consulted a medical journal and then said they thought we had correctly diagnosed it. I had also brought some literature from a physicain in Canada who wrote on his experience with the botfly and how he had surgically removed the larva. So Mr. Surgeon takes me into the O.R. and before I know it my face is deadened and he's making an incision to find the creepy little guy. He fished around for a period of time and I was getting concerned that maybe we hadn't correctly diagnosed it when he suddenly said "my God - you were right!!" and pulled the maggot out and dropped into the bottle Cheryl was holding (she was quite the assistant!). He continued to root around for a period of time to make sure Fred (as we christened him) wasn't a twin and didn't have any roommates or that we hadn't left part of Fred behind!! Fortunately there were no more and I was stitiched up with 2 stitches located just to the side of my eye.

I had a good look at the little guy - who was still moving - and he was identical to the picutres on the websites - white, with 3 stripes that are actually spiny hooks, what looked to be a tail but what we think might have been the breathing tube and 2 little pincers at the front of him. My God, I can't believe it was in me!! I felt immediate relief, both physically and mentally, the swelling around me eye immediately started to subside as did the inflammation.

In any event, that was 2 days ago, it is now Friday March 21 and my face is 100% improved!! There is some swelling from the surgery but less than there was with the botfly and the pain and discomfort is gone, with the exception of the incision. And I am none the worse for the wear.

SO the question everyone keeps asking - would I go to Belize again?? Absolutely!! The chances of this happening appear to be slim, no one else I know who was there had any bites, so I'd certainly take the chance again. The whole expereince does seem rather surreal and as the T-shirts proclaim, it was rather UNBELIZEABLE!!


Thank you for sharing Mark's botfly experience: the pain, humor, lyrics, native remedies, and medical experience and information. If only I'd known of your website sooner I might have saved myself weeks of medical mystery. It was only after the my little companion was determined to be a botfly larvae that I talked to my sister Abi who has spent a lot of time traveling in the remote regions of Central and South America. She was quite familiar with bot flies and turned me on to your website. So here's my story.

In mid November 2002 my wife Bonnie and I spent a week traveling in Costa Rica. We were a few days at Arenal and vicintiy and a few days on the beaches of the Pacific coast. Arenal volcano was spectacular and our guide kept reiterating how fortunate we were to see it; for most of the time it is hidden in the clouds.

About three weeks after we got home [Boston area] from a relaxing week of hiking, exploring, and lounging on the beach I noticed a sore on the shin of my right leg. I had no idea how it got there; no recollection of scrapes or bruises. It was itchy and looked a bit like a bug bite that has been scratched. The surrounding area was red. I didn't think much of it at the time, but two weeks later when it still hadn't healed and was clearly infected I started getting concerned and went to see a dermatologist. He prescribed an antibiotic cream and antibiotic pills. I delayed taking the antibiotic pills because of a concern about drug interactions with the immunosuppressant medications I am as the result of a kidney transplant two years ago. It took me nearly a week to reach the doctor again to get clarification about the safety of his presciption. [ It didn't help that all of this was happening over the Christmas and New Years week when doctors are notoriously inaccessible]. All this time the sore was getting worse and oozing almost constantly. In addition to the itching that I had at the beginning, I had throughout occasional sharp stinging pains usually of only a second or two duration.

On the night of January 3rd the pains were frequent and intense keeping me awake for a good part of the night. By noon the next day, Saturday Jan. 4th, my whole right leg below the knee was extremely inflamed and very red and hot. We headed to the emergency room at Boston's Beth Israel Deaconess Medical Center. The doctors there, knowing that I was a transplant patient on immunosuppressant drugs, took one look at me and said I needed to stay in the hospital and be on intravenous antibiotics to clear up what they called cellulitis. I spent five days there on the IV with my legs elevated as much as I could tolerate. After the five days they sent me home with a PICC line in my arm and automated infusion pump for another week of IV antibiotics. The nasty looking sore on my leg was clearing up, but I still had a quarter inch diameter crater on my leg to which each day I applied a dab of Bacitracin and a bandage.

You can only imagine my surprise when on last Thursday morning [Jan 16] I removed the bandage to find a worm crawling out of the hole in my leg. My wife was totally grossed out and swore she'd never go to a tropical country again. As I was getting ready to go to the hospital to have it removed, it fell out. I put it - still very alive and wiggling- in a small jar to take to my doctor. The worm [larvae] was a dirty white color about 3/16" in diameter and 1/2 -3/4" long. The doctor at first thought that it was a hookworm, but sent it out for analysis which determined that it was a botfly larvae.

The botfly is found throughout Central and South American. Part of its reproductive cycle requires living in the body of a warm blooded host [me]. The female [not wanting to take responsibility for its actions] lays its eggs on the belly of mosquitos and other biting insects. When the mosquito bites a person, the person's body heat is enough to cause a tiny larvae to hatch from one of the eggs. The larvae then burroughs into the body, leaving itself an air hole so that it can breath [and I can ooze]. After 6-8 weeks if left undisturbed the full grown larvae emerges in order to pupate and become a botfly and begin the life cycle all over again.

So, not only had I brought home from Costa Rica a souvenir I was unaware of, but in the process I got an unplanned for lesson in entomology.


Bernie Krause on the Botfly

Though he says he has learned to coexist with animals, tiny bugs are a whole different matter. "There's a bug [the human botfly]," he explains one afternoon, sitting at a picnic table at the edge of his Glen Ellen property. "It lays eggs on the legs of a mosquito when it's in flight. OK. Stop. Think about that. It lays eggs on the legs of a mosquito when it's in flight. Then, when a mosquito bites you, the eggs get deposited in the hole where you were bitten, and then the larva grows and rotates under your skin.

"I got one in the head, on my left temple. I went to the UC Medical Center in San Francisco, and then a dermatologist. I said, "This thing is really hurting me, can you help me get rid of it?' And they would all tell me with authority that it's only a cyst, and I should take antibiotics and it will go away. I took doses and doses, and nothing changed.

"So when I was in Tucson, I was giving a presentation and the pain was so terrible that I started to cry. I told them that I had gotten something from Costa Rica, and I had to go home and go to the doctor. I went to a plastic surgeon in San Francisco, the one who had said it was a cyst, and I said, "Fred, I don't care, I've got to get this off.' He said something like, "I'm in the middle of a boob job or a tummy tuck or whatever,' and I said, "I don't give a shit, you need to deal with this now.' So he cut off the cyst, and in it he took out with a pair of tweezers this spiny thing that was undulating. And he damn near passed out. He couldn't believe I had this thing in my head. That's why it was hurting.

"So it's all the small things, not the large things."

I feel for you, especially since you and the wife had to endure the stupid arrogance of doctors who won't let you help them out.

I came home with 8 in my back (From Belize, by a lake) out of which 7 were extracted by following the traditional method of "airtight" goop suffocation followed be popping them out. My boyfriend became excellent at it, bless his heart, and was trying to let the doctors know as they insisted on digging for the last one themselves. Now I have a nice size scar on my back.

Not to mention, the last bot fly.... boyfriend got that one out as well after it burrowed even deeper, escaping the scalpel.

All in all it's a good drinking story.


For the last six weeks, after a trip to Belize etc, I have had a Botfly larva in my scalp at the back of my head I couldn't see it but I could feel it, as no doubt you can imagine! I went through four doctors in as many weeks (and lots of antibiotics and tests) before eventually meeting one who recognised the problem instantly. c Mark's story was a great source of information and inspiration during the last fortnight , once I knew what to look for. It's always reassuring to know that someone else has survived a much more gruelling ordeal! Botty was removed surgically today. He didn't want to leave and hung on grimly until the resourceful doc gave him a mouthful of saline solution through a syringe.

I was bitten during a day trip from San Pedro on Ambergris Caye to the Mayan site at Lamanai. We went by boat from San Pedro , across sea and through a mangrove swamp to Bomba , then bus overland to Lamanai River and upriver by another boat. I'm pretty sure I was bitten by something resembling a horsefly when our boat stopped briefly in the mangrove swamp. I hope that's enough to identify the place. I don't have Marty Cassado's address, but maybe you can pass this on to him.

We enjoyed our stay at Cha Creek Cottages near San Ignatio (lots of trips and other adventures, excellent service etc) and of course over the border at Tikal. Lamanai was also good, even if getting there carries an infestation risk! Ambergris is a great place for snorkeling ...... many trips on offer though we had little time to sample many. Further up the coast in Mexico are also many good caves and lagoons for snorkeling. I hope you have a great holiday.

Robbie Graham

I have observed how the vet took it out of one of my dogs and thereafter developed my own technique - dunno if I would do it on myself or another human - but at least no drugs of any kind of any kind are involved.

You get a nice fat sewing needle - usually the biggest from the needle kits you buy in the stores for a couple of bucks. I sit down flat on the ground, one leg over the dog's body and the other squarly on his jaw to immobilise him. With one hand I squeeze just under where the wormy bastard is and apply firm, relentless pressure as if I am trying to pop him out of the vent hole. This will force the tip of the alien invader out of the vent hole where I spear him with gusto (his hide is almost leathery) then I pull out and squash.

The vet doesn't bother with the needle he just mercilessly pops him out (after muzzling Fido).

After spending 10 days in the jungles of Belize, I returned home with two 'bites' on my butt. Thinking they were spider bites I left them alone only to have them get bigger and painful. About 4 weeks after getting back from Belize I went to see a doctor. He didn't really know what they were, but suggested soaking them in warm water with epsom salt.

Well, I soaked in a tub of very hot water ( about as hot as could stand ) with Epsom salt for 45 minutes before I went to bed. The next morning.....surprize! Both bite areas had the dead larvae sticking out and both were thus very easy to express. I was too shocked and fascinated to be disgusted.

I guess the combination of being soaked under water that was also very hot killed them. Just thought this may interest your readers as another possible way to get rid of them. Loved your web site.

Thanks, David

Rick and I want to thank you for your Botfly story. We returned from Belize November 16. While in Belize, we had hiked in the jungle on two separate occasions. While I had used insect repellent in my hair and scalp, Rick did not.

About a week after we returned from Belize to Columbus, Ohio, Rick noticed bumps in his scalp that later began to itch. Then they started seeping. Then came the stabbing pain. By the time we thought he should do something about it, it was Thanksgiving weekend and impossible to see a doctor.

So we called a pharmacist friend who said we should alternate cortisone cream with antibiotic cream. I also used a "bite stick" with ammonia in it on the "bites." No improvement. On Monday, December 2, Rick went to his doctor, who diagnosed a bacterial skin infection, prescribing oral and topical antiobiotics.

By December 6 there was no improvement, and the pain would come at any time with not warning and be excruciating. That evening, as Rick sat at the computer, blood began running down his head and side of his face from one of the holes/bites/whatevertheywere.

I couldn't stand it any longer. I started searching on the internet. I used terms like "bleeding scalp" and found lots about head wounds. The next day I was going to go Christmas shopping, but I couldn't stand to see Rick in pain and with no improvement, so more internet searching supplanted the shopping (I made up for it by shopping on the web later). At the Center for Disease Control site, I started looking at different types of insects, came across the botfly and performed another search: "bacterial skin infection botfly Belize" and voila! your botfly article came up. I read it, printed it out (in full color) and took the papers in to Rick. "You're not going to like this," I said.

First we tried meat taped onto his head (shaved portions of his head first) using painters tape and covered by a hat. When we removed the meat, we could find small bore holes in the meat but no larva. (It was great calling him "meathead" all weekend.) Then we moved on to Elmer's school glue. Seemed those little buggers could "eat" through the dried glue and breathe all the same.

By Monday December 9, Rick had faxed your article to his doctor, who said to try superglue. This did the trick. We had been afraid to kill the suckers while still imbedded in the skin. Seems that superglue works because it dries so fast, and you can glob it on. When we peeled back the superglue, part of the larva was sticking out of the skin (must have been trying to get air and got caught). The dead larva could be pulled out by the part sticking out (using a kleenex when grasping it), but the surest way to get them out was to squeeze them out (a couple of times they shot 2 feet into the air which meant I jumped about 2 feet myself.) One time, when one was pulled out, only half of it came out, with the remainder having to be squeezed out. I got all out but one, covered it with antibacterial cream and watched it with a light and magnifying glass. Sure enough, the cream was showing a bubble. These babies definitely won't squeeze out if still alive. One more application of superglue did it, and the next morning, the last one jumped out to greet the day with an easy sqeeze.

Just thought you'd want to know about the superglue treatment. Definitely the most effective and efficient. Turns out Rick had 5 botfly larvae in his scalp.

We dropped them into a half-full miniature bottle of Jack Daniels (kind of like the worm in the Tequila) and sent them off to his doctor who definitely wanted to examine them.

All the while I cared for Rick (and the botflies), I kept saying that part of the wedding vow to myself, "In sickness and in health." When those nasty things came out, I couldn't stop saying, "You poor man, you poor man." (You see, when he'd stop in the middle of walking, hold his head in pain and grimace and yelp, I had been a bit skeptical before I knew what these things were. Now, I will never doubt him when he says he is in pain.)

THANK YOU, for putting your article on the web. Who knows how long it would have taken to get a correct diagnosis in Columbus, Ohio? We are grateful to you.

Jennifer and Rick Brunner

P.S. When a buddy of Rick's heard about his botflies, he e-mailed Rick saying, "You know I always thought your wife looked like Sigourney Weaver, but don't you think you're taking this alien thing a little too far?"

Thanks again.

Several parts of this story and the photos are from Brenda Johnstone,, email [email protected]. Much thanks to her for her information and her permission for us to use it.

Here's a recent question and answer....

Hi, I've read your stories about botflies. My son studying for a semester in Belize and has a botfly. He does not want it removed yet because he finds it interesting. What can I say? My question is, what are the side effects for him, long term, short term? I'm very concerned and obviously if he were home I would insist he have it removed.

Here's a response from a medical person.... The maggot can be allowed to run full cycle/term,
There will be no averse effects such as secondary infections.
There is no need for medications.

Birth of A Botfly Maggot

Mark W. Moffett is the only human male to have given birth -- watch the video for proof!

This amazing video is excellent mealtime viewing, so sit down at your desk, pull out that sandwich and get ready for a fascinating story about biodiversity!

Mark W. Moffett (a.k.a. "Doctor Bugs") tells his horrifying yet humorous tale of the parasitic botfly larva that drilled its way into the back of his hand during an expedition to Belize. The maggot took ten weeks to grow to "maturity," surviving Mark's subsequent trips to Honduras, Botswana, and Zimbabwe. It finally emerged on 2 December 2010, at the end of a meeting with ant expert and environmentalist E.O. Wilson at Harvard.

Alien (within us): Human Bot Fly Removal

A family vacation in Belize in December 2008....... Nightmare for one family member..............

Two weeks after returning from an otherwise wonderful vacation, he begins to develop a 102 degree fever which lasts for two weeks. He experiences random bleeding from three small, infected wounds on his left elbow. He sees four different internists and after two rounds of antibiotics is still suffering from the symptoms. It turns out that he had three bot fly larvae growing in his arm. This video shows the removal of the larvae.

Bot flies (Order Diptera, Family Cuterebridae) are large, stout bodied, hairy flies that resemble bumblebees. The botfly egg is deposited by a mosquito or sometimes by another insect. The larva grows in the host's body until it is fairly large. The botfly larva can easily be killed by taking away its air supply -- by putting vaseline or similar on the skin where the lump is, but then you still have to extract the larva.

Adult botflies have nonfunctional mouthparts and do not feed. Larvae of this species parasitize wild and domestic rabbits. Females deposit their eggs in or near the entrance of their host's burrow. Bot fly larvae penetrate their host through the skin or natural body openings after hatching. The larvae form a tumor (called a warble) in the subdermal zones of their host and remain at this location until larval development is complete.

Larval development varies among species, ranging from 20 to 60 days. Before pupating, the larvae leave the host's skin and drop to the soil.

The Human Bot Fly

Raising two dipteran children was an interesting experience. It was embarrassing on a few occasions, when both of my arms started bleeding profusely in public; painful at times, to the point of waking me up in the middle of the night; and inconvenient during the last stages of the flies’ development, when I had to tape plastic containers to my arms to make sure that I will not lose the emerging larvae. But other than those minor discomforts it was really not a big deal. Perhaps my opinion would have been different had the bot flies decided to develop in my eyelids, but I actually grew to like my little guests, and watched their growth with the same mix of pleasure and apprehension as when I watch the development of any other interesting organism under my care.

Having two bot fly larvae embedded in my skin have also made me ponder once again the perplexing element of the human psyche that makes us abhor parasites but revere predators. Why is it that an animal that is actively trying to kill us, such as a lion, gets more respect than one that is only trying to nibble on us a little, without causing much harm? I strongly suspect that it has to do with our genetically encoded sense of “fairness” – we perceive parasites as sneaky and underhanded, whereas predators attack us head-on and thus expose themselves to our retaliation. They are brave, or so we think. This, of course, is a very naive and anthropomorphic interpretation of nature. A lion is no “braver” than a bot fly, who has to skillfully hunt mosquitos to assure the dispersal of her eggs and risk more dangers than a lion, a top predator with no natural enemies. Most importantly, to a bot fly we, humans, are a renewable resource – it is in the bot fly’s best interest that we live a very long life and thus can be “reused” – hence the minimum amount of suffering that this species causes. To a lion we are nothing more than a one-time meal. But we should not judge either species for their actions – there is no “good” or “bad” in nature – nature is amoral.

I am saying this to prepare you for a short video that I made about my experience of raising a bot fly. I don’t want you to think that it is “creepy” or “weird”. It is simply a documentation of an interesting organism, who happens to develop in the skin of large mammals. But please be forewarned that this video includes a few sequences that some viewers may find disturbing. If you don’t want to have nightmares about things living inside you (which they already do, by the way), please don’t watch it. But if you are prepared to be open-minded and appreciate God’s wonderful creations in all their amazing glory, enjoy the show!

The botfly larvae

One of the really cool things about a botfly is that it lays its eggs on a mosquito and the eggs hatch when the mosquito feeds on a host. Do humans get warbles? Yes, (are you disgusted yet)?

While the maggot feeds on its host (you or one of your pets) it has to have a hole in the skin so it can continue to breath. It takes about 6 weeks to complete development on its host.

If you treat (kill it) when the worm is small, your body will absorb it. If it has developed when treated, it will die and you can squeeze it out a day or two after the hooks have relaxed.

Tiger Balm can be found in Belize at most stores- I would recommend just dabbing a bit over any fly bite you receive. Generally that eliminates the itch, etc. and helps not to make your body into a host!

And if you are fortunate enough to be a host - enjoy the science lesson!

Not up to that? Locate the breathing hole and cover it with a little tobacco or heavily camphorated oil soaked cotton - tape over vent hole - the worm comes out - 12 hours later pull off the tape - voila - one grub, maybe two or three-- no infection -- everything ok!

Source of botfly worm? My dog who is currently glaring at me in a corner but who no longer has any parasites hidden under the skin!

Size - adult and juvenile larvae.

Note the “hooks” that hold it in place!

Almost ready to be expelled from host.

by Michelle D de Gonzalez for Creatures of Belize

Here and here is a bit more on botfiles if you are still interested....

And a bit more ....

Commons Island Community History Visitor Center Goods & Services Search Messages

Copyright by Casado Internet Group, Belize