Bot Flies, aka warble flies, heel flies, gadflies, are common in Belize. The word “bot” in a sense means maggot. They are true parasites, meaning they live off the host without harming it.
The adult female bot fly lays between 100-300 eggs. The eggs of the bot flies are transmitted to animals such as cats, dogs, horses, as well as humans, through the flies themselves, or through the bite of mosquitos. The eggs burrow under the skin (and sometimes enter the intestinal tract when animals lick the eggs off their skin) of the host, where they form as maggots. Signs of bot flies on pets (and humans) are a raised bump (referred to as a warble), with a hole in the skin. The hole remains open allowing the maggots to breath.
There are several ways to remove them, the most common is to squeeze the base of the lump until the maggots come out. Another common treatment is to cover the hole with petroleum jelly and cover that with sticky tape (duct tape works well). The Vaseline prevents air from entering so the maggots surface to breathe then stick to the tape. When the tape is removed the bot fly maggot should come with it.
Alternative three is to take your pet to a licensed veterinarian for treatment.
Annie, the cat who inspired this story was treated by a vet and is recovering well. Her foster mother, who watched the removal, still gets nauseous when she thinks about it.