Small But Deadly: The Deadliest Insects In The World

Discover the surprising deadliest insects worldwide! Learn how to protect yourself from these dangerous bugs with expert insights from Spidexx Pest Control

Kristin M.

Published On:

October 17, 2023

Last Updated:

October 30, 2023

Close your eyes and picture a deadly animal. Maybe you thought of a pouncing lion, or a king cobra ready to strike. But did you imagine anything with six legs? You might be shocked to learn that insects are collectively responsible for over one million deaths per year worldwide. In fact, according to lists compiled by both CNET and Business Insider, insects account for 5 of the 10 deadliest animals to humans yearly! While you won’t find most of these biting and stinging insects in your backyard, learning which insects are the most deadly as well as where they reside will help you better understand how to stay safely out of their way. If you find yourself bitten or stung by any of the following, contact your doctor or healthcare provider immediately.

Killer Bee

Killer bees originated in Brazil but can now be found in much of the southwestern United States. In 1956, scientists were trying to breed a bee that was better adapted to the tropics of South America. But the bees had something else in mind. In 1957, they escaped the lab and began breeding with local Brazilian honeybees, and they have been expanding their range about 200 miles per year ever since. In 1990 they were first detected in the United States in Texas and have now spread into most of the southernmost states. These bees can chase people up to a quarter of a mile from their hives and are very aggressive. These bees each have less venom than other types of bees, but since they swarm more than other species you might not notice this while being stung. There is some good news here–despite their frightening name, these bees have only killed a dozen or so people in the United States in the 30 years they have been here.

Fire Ant

Fire ants are another species that originated in South America. Unfortunately for us, they are now found across the southern United States from California to Florida. They get their name from the burn their sting causes. As one of the most aggressive ant species, these ants release pheromones when they swarm perceived intruders, in order to summon more ants from the colony. Just a few fire ants can quickly become an entire swarm. In addition to calling in reinforcements, these ants use their pincers to anchor themselves in one place while they sting repeatedly in an outward circle. After about a day, the sting will form into a white pustule. Though the stings of these ants are quite painful, they are not usually deadly. Fire ants kill about a dozen people yearly in the United States.

Asian Giant Hornet

Asian giant hornets are another insect that started on a different continent but have spread too close to home for comfort. Native to eastern and southeast Asia, this insect has made its way into the Pacific Northwest, probably via accidentally being trapped in shipping containers within its native habitat before being sent overseas. But there is nothing accidental about this hornet’s attack methods–its stinger is over a quarter of an inch long. That may not sound like much, but it is long enough to pierce standard beekeeping suits! Running is also not advised, as this causes the hornet to want to chase you more. They are also attracted to the smell of human sweat as well as alcohol and sweet flavors. Should you find yourself stung, their venom can cause kidney failure and death. These insects are responsible for the deaths of approximately 50 people yearly.

Assassin Bug

Despite its fearful name, the assassin bug won’t kill you. However, it just might transmit a disease that can. It is transmitted through the feces of assassin bugs, also called kissing bugs because they usually bite near mouths due to their attraction to the carbon dioxide we exhale. Though these can be found in the United States, remain calm unless you are seeing one while traveling through Central or South America. This is because Chagas disease is largely endemic to these regions, meaning it is found and spreads more regularly there. In fact, the CDC reports that most of the people in the US with Chagas disease were infected in Latin America and only a few cases from direct contact with the bugs have been documented in the United States. Despite the low numbers of deaths in America, this insect’s death toll must still be respected: Chagas disease kills approximately 10,000 people worldwide yearly.

Tsetse Fly

The tsetse fly is a far deadlier member of the house fly family that lives in tropical Africa. As with the assassin bug and the rest of the insects rounding out this list, the bite itself is not deadly but the diseases transmitted by them can be. Unlike most species of fly, both males and females bite. Male tsetse flies bite humans, while females aim for larger mammals like cattle, horses, camels, and antelope. But any host that is bitten runs the risk of developing sleeping sickness, which always ends in death. The tsetse fly also contributes to death in another way: famine. When sleeping sickness affects livestock animals, they can no longer work, breed or help fertilize the soil. For this reason, while the tsetse fly kills 10-12,000 people per year due to sleeping sickness alone, its death toll is certainly higher due to its devastation of available food sources and fertile land.


Found on every continent except Antarctica, the mosquito is one of the most prevalent and well-known pests in the world. While it might seem merely annoying, the mosquito is actually responsible for more deaths than every insect on this list so far combined. They alone are responsible for over one million deaths worldwide yearly, making them the single deadliest animal in the world. Again, it is not their bite that is deadly–they are vectors for multiple viruses and parasites. They detect us via observation, chemical signals, and infrared radiation emitted by our blood. As they travel they can pick up a disease or parasite from one host and then pass it on to others. Worldwide, they spread dengue fever, malaria, yellow fever, and the zika virus. Of these, malaria is responsible for the most deaths, having killed over 400,000 people in 2017 and again in 2018. In the United States, they spread West Nile virus. According to the CDC, the number of severe cases of West Nile virus was almost 25% higher than it had been than the average for the past 10 years. While this particular virus is usually mild, there are around 2,000 cases of malaria yearly in the United States as well–so it is a good idea to visit your doctor if you begin to feel ill after having been bitten by a mosquito just to be on the safe side.


Found all over the world, fleas are generally regarded as more of a pest than a killer. And to be fair, this is usually true! You may have seen your cat or dog scratching at a flea, given them a flea collar, and never had another problem. But historically, fleas are responsible for one of the deadliest events in history: the Bubonic plague. Since different fleas feed from different host species, scientists and historians know specifically that the rat flea was responsible for the “Black Death” or bubonic plague in the 1300s. As the fleas’ rat hosts became infected and died, the fleas found another food source and plague target: humans. Beginning in China and killing approximately 60 million people (half its population at the time), the plague spread to Europe by ship in the late 1340s. By its end in the 1350s, the death toll was in the tens of millions. Between 20 and 50 million people–30 to 60% of Europe’s population–had been wiped out, not including countless domesticated animals. Though their historical death count due to plague has been catastrophic, currently fewer than ten people are infected in the United States yearly, and these infections are treatable with antibiotics.

Deadly but Avoidable

Knowing which insects are the deadliest and where they are found allows us to avoid them if possible or at least better arm ourselves against them. Modern medicine has found ways to cure or at least lessen the symptoms of most of these illnesses and avoiding trips to Africa puts you out of range of the tsetse fly.

But for the worst offender–the mosquito–Spidexx is happy to offer our professional services! During the spring and summer, we offer ongoing treatments for your backyard, as well as one-time services for events. And if you find fleas are bugging you, we also have you covered! To learn more about our services, give us a call today at (844) 922-7732 or fill out a contact form below.

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