Science, Tech, Math › Animals & Nature 3 Common Bugs That Can Kill You Share Flipboard Email Print Animals & Nature Insects Basics Behavior & Communication Ants. Bees, & Wasps Beetles Butterflies & Moths Spiders Ticks & Mites True Bugs, Aphids, Cicadas, and Hoppers Amphibians Birds Habitat Profiles Mammals Reptiles Marine Life Forestry Dinosaurs Evolution View More By Debbie Hadley Entomology Expert B.A., Political Science, Rutgers University Debbie Hadley is a science educator with 25 years of experience who has written on science topics for over a decade. our editorial process Debbie Hadley Updated February 25, 2019 Bugs — insects, spiders, or other arthropods — far outnumber people on this planet. Fortunately, very few bugs can do us any harm, and most are beneficial to us in some way. Despite science fiction movies portraying giant, bloodthirsty spiders or enraged swarms of killer bees, there are few arthropods that should inspire fear in us. That said, a small number of bugs are worth avoiding, and you might be surprised to learn how some common insects can be deadly. By hosting and transmitting pathogens that cause diseases, these three common bugs can kill you. Fleas Getty Images/E+/spxChrome Don't panic just yet. Fleas infesting Fido and Fluffy can be a nuisance, for sure, but they aren't likely to kill you. Cat fleas (Ctenocephalides felis), the species commonly found on pets in North America, can cause allergic reactions to their bites, and occasionally transmit diseases to humans. Still, cat fleas aren't a cause for concern. Oriental rat fleas (Xenopsylla cheopis), on the other hand, are the infamous carriers of the plague. Rat fleas carry the bacteria Yersinia pestis, which caused a medieval pandemic that killed 25 million people in Europe. Thanks to modern sanitation practices and antibiotics, we aren’t likely to see such a deadly outbreak of the plague again. Although flea-borne plague infections are rare today, people do still die of the plague each year. Even with antibiotics available, about 16 percent of plague cases in the U.S. are fatal. During one 5-month period in 2015, the CDC tallied 11 cases of human plague in the U.S., including three deaths. Plague-carrying fleas are found mainly in the western states, and anyone who engages in activities near rodent habitats should take precautions to avoid contact with rat fleas. Mosquitoes Mosquito Totem. Douglas Allen / Getty Images Many people flinch at the sight of a spider or frantically swat away an approaching bee. But few people panic in the presence of the insect that kills more people annually than any other — the mosquito. Mosquito-borne diseases kill over one million people worldwide, each and every year. The American Mosquito Control Association states that malaria, just one of the many deadly diseases carried by mosquitoes, kills a child every 40 seconds. Mosquitoes carry everything from dengue fever to yellow fever and transmit parasites that affect horses, livestock, and domestic pets. Although U.S. residents shouldn't worry about malaria or yellow fever, mosquitoes in North America do transmit viruses that can lead to death. The CDC reports there have been over 36,000 reported cases of West Nile virus, and over 1,500 of these resulted in death. Almost 600 cases of Zika virus have been reported in U.S. territories in the Caribbean. Ticks Getty Images/E+/edelmar Like mosquitoes, ticks transmit a number of pathogens that cause human diseases, and some can be fatal. Tick-borne illnesses can be tricky to diagnose and treat. Tick bites often go unnoticed, and the early onset symptoms of tick-related illnesses mimic other, more common maladies, like the flu. In the U.S. alone, diseases caused by tick bites include anaplasmosis, babesiosis, Borrellia infections, Colorado tick fever, Ehrlichiosis, Heartland virus, Lyme disease, Powassan disease, rickettsiosis, Rocky Mountain spotted fever, Southern tick-associated rash illness, tick-borne relapsing fever, and tularemia. Lyme disease can cause cardiac symptoms similar to a heart attack, sometimes resulting in death. In the U.S., eight people have died as a result of Powassan virus infections since 2006. Since the CDC began tracking Ehrlichiosis infection rates, the fatality rate has ranged from 1-3 percent of all reported cases each year. Make sure you know which ticks live in your area, which diseases they may carry, and how to avoid a tick bite that can lead to a serious, if not deadly, illness. Arboviruses (Arthropod-Borne Viruses) The Centers for Disease Control and Prevention provides information about how to recognize, treat, and avoid arthropod-borne diseases. The United States Geological Survey hosts interactive disease maps to track cases of West Nile virus, Powassan virus, and other arthropod-borne illnesses. Sources "Human Plague – ," Morbidity and Mortality Weekly Report, August 28, 2015, Centers for Disease Control. Accessed online April 25, 2017.United States, 2015"Mosquito-Borne Diseases," American Mosquito Control Association. Accessed online April 25, 2017."Tickborne Diseases: Widespread, Serious, and Taking Us by Surprise," by Maryn McKenna, National Geographic, August 31, 2015. Accessed online April 25, 2017.