Warbles in Rabbits Caused by the Bot Fly

warbles in rabbitsHow do you recognize a Bot fly problem in rabbit? Symptoms of Warbles show up after the Cuterebra fly deposits an egg on the skin of the rabbit. It is one of the rabbit facts you should know about as you begin raising rabbits on your farm or homestead. Warbles in rabbits, is self limiting, and usually not fatal. However, the symptoms of warbles in rabbits can be both alarming and rather disgusting.  In addition, warbles in rabbits can impact the economic return on meat rabbits and rabbit pelts.

Bot Fly Symptoms – How the Cuterebra Fly Causes Warbles in Rabbits 

Flies are a nuisance. This is common to any area with livestock, manure and moisture. Bot flies are different than regular run of the mill flies. The Cuterebra fly is large, somewhat resembling a large bumble bee. It doesn’t take many Cuterebra to cause a problem in your rabbits.  The bot fly lays a single egg, either on the rabbit, or on the vegetation near where the rabbits hang out. Either the egg hatches and the larvae burrows into the skin of the rabbit, or the eggs are picked up on the fur of the rabbit as it grazes by a plant or something else. The larvae hatch and make their way under the skin of the host rabbit, grow and mature. The larvae stage feeds on secretions from the host. Pretty unpleasant, right?

The rabbits don’t seem to be bothered by the growing larvae although some mild scratching at the site might be noticed.  Our rabbits continued with normal eating and activity.  The first thing I noticed was a large cyst type growth on the back of one rabbit.

warbles in rabbits

The “cyst” that wasn’t 

I was familiar with the bot fly and the yellow sticky eggs as they are a concern with other livestock.  However, I did not think about this as the cause of the large lump growing on my older male rabbit.  Mistakenly, I assumed the poor old boy had some sort of tumor and would be leaving us shortly. I kept a close watch to see if he was suffering, acting sick, not eating, but none of those things occurred. Quincy continued to eat normally, play with his hutch mate, Gizmo and do normal rabbit activity.

I am not against taking a rabbit to the veterinarian, but Quincy was not acting sick! I thought there was a possibility that the abnormal growth was a benign cyst and not  a malignant tumor. Surely I didn’t want to think about the possibility of a bot fly larvae growing beneath the skin. Fast forward a couple of weeks, and I noticed that the “growth” had gotten considerably smaller overnight.

warbles in rabbits

I examined the lump and found it to be oozing fluid and pus.  After cleaning the area, cleaning the wound it was clear that whatever it was had burst and was draining.  I had been taking photos all along to show to a veterinarian if I needed to take the rabbit to the vet’s office. I remembered a friend who had been raising rabbits for many years.  When I showed her the photos and she suggested that I look up warbles in rabbits.  The symptoms of what I had been observing were exactly the same. We even had the distinctive round hole, where the larvae had crawled from the host rabbit. Yuck! Things continued to get even more disgusting!  Warbles in rabbits is not for the faint of heart!

I did even more research,and placed a call to the veterinarian.  He confirmed what I suspected and agreed with my treatment plan for warbles in rabbits, which I will explain in a moment. I checked the other rabbits in the rabbit area. Gizmo had a few smaller lumps on him, actually he had five lumps but it was too soon to be sure they were warbles.  Quincy had one other smaller warble.

warbles in rabbits

With my vet in agreement, I was to let the infestation run it’s course from this point. He could have done the extractions, surgically in his office but we chose to carefully monitor both rabbits and perform twice daily wound care. The holes are actually fairly easy to clean and treat, if you can stand to do it yourself. I have a fairly high tolerance for grossness so I opted to do it myself. Treating the wounds is similar to treating a deep tissue wound or puncture wound. Keeping it clean and dry is key.

Why does this happen?

Sanitation and cleanliness are important when raising any livestock, fly issues can still occur, even in the best of rabbit care. Conditions of extreme wetness at just the right time can give the Cuterebra fly the right situation to lay her egg. The larvae burrow into the skin of the host rabbit and it takes a while before you notice the growth developing. By this point, many bot flies may have laid their eggs on the rabbit or other rabbits in the area.   Although cleanliness is important, the fact that you end up with warbles in rabbits does not necessarily mean that you don’t do a good job of keeping the rabbit area clean.

Bot Fly Symptoms  –  Cuterebra fly attack

The bot fly deposits one egg on the skin of the rabbit.  The larvae matures under the skin of the rabbit, creating a large, hard mass that looks like a tumor or cyst.   When you examine the lump you may notice a hole that the larvae is breathing through or it may simply be a soft crusty area on the skin.  The rabbit seems to not be bothered by the examination or by hosting the creepy crawly larvae.  

Bot Fly Removal 

Removal of the larvae causing warbles in rabbits should be performed by a veterinarian.  If you squeeze and accidentally squish the larvae it releases a deadly toxin which can send the rabbit into shock and result in death.  The larvae can be difficult to remove and require quite a bit of pulling, all the while trying to not squish it.  It’s best to leave that to the Veterinary professional.   As our rabbits bots were about to emerge, the skin around the breathing hole would thin out, and get crusty.  At this point I was extremely careful to check twice a day, so I could immediately begin wound treatment and ward off  further infection.  

Even though I was vigilant, I never actually saw the bot larvae emerge.  

warbles in rabbits

Treatment of Warbles in Rabbits

After the larvae emerges, a hole is left. Sometimes, an infection has already started in the wound. The hole left behind when the larvae emerges requires twice daily care for the first week. If the wound is healing well, I then went to once daily wound care. Take care to keep the area clean and sanitary during the healing so you don’t attract more flies. House flies will be attracted to the fluids oozing from the wound and you don’t want to end up with a case of maggots or fly strike on top of warbles in rabbits.

warbles in rabbits

The products I use to treat the wound are commonly available.  

Clean the area.  Trim away any fur that is in the way, or that may get stuck on the drainage. 

The wound should not bleed or only bleed a little.  

1.Flush the wound inside the hole with a sterile saline solution.  I flush, then mop up the fluids, then flush again.  I try to flush out as much debris as possible to aid in healing.  

2.I use a product called Vetericyn, that is sold in many pet supply or farm supply stores.  I spray this into the hole and around the outside of the wound.

3. Last, I squeeze a good bit of triple antibiotic cream into the hole.  (CAUTION: DO NOT use a triple antibiotic cream with pain reliever included)   

warbles in rabbits

What other animals can be victims of Bot Fly ?

Horses

Cattle

Sheep

Goats 

Cats

 Dogs 

Humans

Wildlife

In livestock the bot fly often lays its egg on the grazing area and is eaten or inhaled by the animal.  The larvae will migrate through the host animal ending up under the skin.  

Cats, dogs, rodents, and other wildlife will contract the bot fly larvae by brushing by the egg after it is laid.  

Warbles in Rabbits is Not the End of the World.

Warbles in rabbits in self limiting, meaning it should clear up without major infection or complication.  If the wounds are not healing and progressively getting better, it is best to seek the advice and care of a veterinarian.  If you feel at all uncomfortable or ill equipped to perform the wound care it is best done by a veterinarian, also. Everyone’s comfort level in dealing with wounds and illness is different. You and your veterinarian are the ones to make this decision. Even though you will be at least a little disgusted by the whole issue of warbles in rabbits, it is something that you can take care of easily. Time consuming? Possibly. Especially if you have multiple rabbits in your colony. 

If you have had personal experience with warbles in rabbits, please share your experience in the comments.

warbles in rabbits