This post started out as a simple post about the annoying blister bugs we have around our home in northern Ghana. On many occasions they have caused horrible blisters on Heidi and myself and I wanted to learn more about them. I got lost for hours following rabbit trails as I researched the subject and it just continued to get more and more interesting. Nothing is ever as simple as it seems. And I kind of love that.
Northern Ghana’s Green Blister Beetle
My first step is always to find out what the locals call it. No one I talked to was familiar with the phrase “blister bug.” This particular bug – actually a “green blister beetle” – is known locally as abdulatanka. That’s not a word in an indigenous Ghanaian language but Pidgin English for “Abdullah’s Tanker” – a reference to a Muslim guy driving a fuel tanker. Why? Because the green blister beetle leaks a toxic fluid and has a tanker-shaped back side. Plus the stereotypical big-rig driver in Ghana is a Muslim man with an Arabic name.
There’s a whole scientific family of blister beetles name Meloidae with around 3000 species. One genus in that family is Lytta and the offending blister bug in our encounters seems to fall in that group.
Male blister beetles secrete an odorless, colorless liquid called cantharidin. It is meant to be passed on to the female after mating as a copulatory gift (aww, how sweet). Afterwards, the female beetle covers her eggs with it as a defense against predators.
That’s right, it’s a defensive agent. Cantharidin is a highly toxic, blistering agent that causes chemical burns. When ingested it can be lethal and there is no known antidote. In fact, it’s a known veterinary issue for horses to be killed by consuming feed containing dead blister beetles.
Historically, cantharidin has been used as a poison and also an aphrodisiac (!). Hmm, those seem to be polar opposites. More on that later…
How Do The Beetles Infect You?
Here in northern Ghana, the green blister beetles are very common and are attracted to lights at night. So we often find them on the screen door of our home and they sometimes get into the hospital at night.
Every time a green blister beetle has gotten me, it just landed on me and I instinctively flicked it off. Usually I don’t even pay it any mind or notice what it is. Then several hours later, the area starts to itch and turn red. A few more hours and I’ve got a big, central blister often surrounded by smaller blisters in the affected area.
On a few occasions Heidi has been been in the middle of surgery and realized one was under her gown in her scrubs! They’ve left some horrific burns on her skin.
Here’s the typical progression of the wound:
How Do You Treat a Blister Bug Burn?
Technically, what I call a “blister bug burn” is called by smart doctor folk (like Heidi) “blister beetle dermatosis and a vesiculobullous skin disorder.”
The number one preventative measure is to wash the affected area as soon as possible with soap and water. One must be very careful not to touch the affected area and spread the invisible liquid to another part of the body. I once got a burn on my eyelid and it was awful! I must have flicked a blister beetle off my body without realizing it and then rubbed my eye with my finger.
Continue to keep the area clean after the blister forms and pops or drains. One can use cold compresses to reduce swelling and irritation. Topical mild steroid creams or antihistamines can also be applied to facilitate healing. Finally, if the primary lesions are infected, oral antibiotics might be necessary.
The Myth of the Spanish Fly
Strangely, historians record cantharidin‘s use as an aphrodisiac far back as Caesar Augustus’s court in ancient Roman times. It was found that when men ingested small amounts of cantharidin extracted from crushed beetles, it had the effect of… well, it was like an ancient viagra.
Its use continued throughout the Middle Ages and the green blister beetle acquired the name of “Spanish Fly.” In more modern times, people started to make the connection between the Spanish Fly aphrodisiac and the horrible deaths it caused when people easily overdosed on it.
One story from 1954 involves an American man who laced two co-workers’ drinks with “Spanish Fly” hoping to have an exciting evening. Instead, the two women ended up dead and he was caught red handed faced because his face was covered with blisters from exposure to the chemical. He ended up serving five years for man-slaughter.
Today, many countries (including the US) have banned cantharidin aphrodisiacs and “Spanish Fly” has become a more generic term for all sorts of “natural” aphrodisiacs available on the market (none of which are FDA approved). The term was so common in pop-culture in the 70s and 80s that it even inspired a (horrible) film by the same name. It also showed up in a Beastie Boys song (“Brass Monkey“) and a Bill Cosby stand-up routine. The latter is no longer a joke considering Cosby’s recent convictions for sexual assault in which he drugged his victims.
Surely There’s Some Positive Aspect to Cantharidin?
There are some veritable, positive uses for blister beetle’s juice. In “Cantharidin Revisited A Blistering Defense of an Ancient Medicine,” physicians argue for its medicinal uses in dermatology. The chemical has been proven to work well in treating warts and molluscum when administered by knowledgeable physicians.
And finally, the high school version of me couldn’t resist but point out that in ancient China, green blister bugs were mixed with human excrement, arsenic, and wolfsbane to make the world’s first recorded stink bomb. BOOM!