Early March was filled with headlines like “How Animals Kill People: By the Numbers”, “These animals are most likely to kill Americans. Hint, it’s not sharks or snakes”, and “Forget sharks: Study finds bees, dogs are the real killers”. That’s because Dr. Jared Forrester and his colleagues published an update to their previous report on the fatalities caused by animals in the United States.
Bees — along with their Hymenoptera cousins wasps and hornets — featured prominently in the report as the group of animals responsible for one of the highest number of deaths between 2008 and 2015. More than snakes, spiders, crocodiles and, yes, sharks.
So these headlines, while sensational, are accurate. But they really should be served up with a sizable portion of context, too.
For example, here’s a selection of the data on animal-related deaths which supports the headlines.
And here’s the context.
Sure, bees might be more dangerous than sharks. But heart disease is way more dangerous than either animal.
“Yeah, I would agree with you on that point,” says Dr. Forrester. “It makes for sensationalistic news. But if we take even a further step back and look through a public health lens at what are the real big causes of human death, animals don’t come close to the top of the list.”
So what’s the real take-away from a report like this?
First, says Dr. Forrester, is to understand that being outdoors and encountering wild animals is not nearly as deadly as most people seem to fear. It’s our interactions with the more common animals in our lives that cause a far greater number of fatalities.
Second, these interactions can be particularly deadly for specific segments of our population, not everyone equally. And knowing this can help us develop sound strategies to reduce deaths that are often preventable.
Third, understanding how to effectively respond to these interactions when they do occur can make all the difference. This seems particularly important when it comes to encounters with the sharp end of a bee. “For those that are allergic, rapid administration of epinephrine and Benadryl is critical,” says Dr. Forrester.
For most people, the venom in a bee sting results in a small localized reaction: pain, itching, redness and swelling. Annoying but definitely survivable. However, for folks who develop a hypersensitivity to the venom, life-threatening system-wide reactions can occur. When the bee venom enters the body and bumps into antibodies, histamines are released. These substances cause the bronchioles in the lungs to constrict and the blood vessels to dilate; breathing becomes difficult and blood pressure drops. On top of that, vascular permeability is altered; fluid flows more easily into the cells and causes swelling of the airways, lips, tongue and throat. Deprive the body of oxygen for too long — either because you can’t take enough in or it’s not circulating effectively to the body’s cells — and the situation becomes dangerous fast. Hence the need for rapid administration of epinephrine or antihistamines. (Epinephrine dilates bronchioles, constricts blood vessels and reduces vascular permeability.)
Only three percent of adults and about one percent of children under the age of 17 develop a severe allergy to bee venom. Fatalities also skew towards older adults, but in an even more lopsided way: nearly 80 percent of the deaths occur in adults older than 40 while only about two percent occur in people younger than 20. Men are twice as likely as women to develop hypersensitivity, but this could simply be a matter of exposure: it takes being stung at least once to become severely allergic, and this hypersensitivity is more likely to develop if a person has been stung repeatedly over a short period of time. And family history matters, too: if other members of your family are allergic to bee venom, your chances increase.
Now consider this: There are nearly 4,000 species of bees in North America. If you are allergic, do you need to be concerned about all of them?
“So, all bees have stings,” says Dr. Joe Wilson, associate professor of biology at Utah State University (Tooele) and co-author of the book “The Bees in Your Backyard”. “But not all are able to sting humans due to the reduced size of the sting.”
To clarify: “sting” is the correct biological term for both the physical pointy end of a bee and the action of using it. The sting is the vestigial remains of what was once an egg-laying tube for bees. Therefore, only female bees have one. (Eggs are now laid through an opening at the base of the sting.) And the size of the sting obviously varies with the size of the bee. For example, bees in the Andrenidae family (which includes species smaller than a mosquito) are unable to sting people because of their reduced sting size.
“I do not know if that means they can’t sting anything or if they just can’t sting humans,” says Dr. Wilson. “I think we should consider all other species able to sting, though they have a wide variety of how painful the sting would be.”
Honey bees are the most well-known culprit. However, bumble bees can also sting, and increased attention has been given to hypersensitivity to bumble bee venom as these species are being used more frequently for commercial vegetable production. The chemical composition of honey bee and bumble bee venom is different, raising the question of whether severe allergy to one will also result in severe allergy to the other. The mechanism by which these two types of bee sting is different as well. Honey bee stings have barbs that catch on the skin; as the bee pulls away, the sting is pulled out of the female’s abdomen — meaning she can strike only once in her lifetime. In contrast, bumble bees (and all other bees, for that matter) have smooth stings and can strike repeatedly.
The honey bee (Apis mellifera) is only one species out of the thousands in North America, and there are only 46 species of bumble bees (Bombus spp) in this same part of the world. On the other hand, there are over 1,200 species in the Andrenidae family. The vast majority of bees in North America are not known for stinging humans, and it’s not even clear how many of them can.
So with all of this in mind, how concerned should the average American be about death by bee? Statistically speaking, not much at all. But context matters, right? If you happen to have been dealt a hand that predisposes you to hypersensitivity and you’re regularly exposed to the right kinds of bees (the kinds which happen to be commonly found around humans), then it can be a very big deal indeed. And these headlines don’t seem so sensational after all.