Assassin bug(01 of10)
Open Image ModalTriatoma infestans Look out for it in: Mexico, Central and South AmericaWhy you should fear it: Assassin bugs transmit Chagas disease, a long-term, chronic disease that can ultimately cause serious cardiac and digestive problems. Notorious victim: Charles Darwin met one on his first trip to Argentina.
Fire caterpillar(02 of10)
Open Image ModalLonomia obliqua Look out for it in: Brazil, Argentina, and neighboring countriesWhy you should fear it: The caterpillars release a powerful toxin that can cause internal bleeding and massive organ failure.Notorious victim: A young Canadian tourist walked barefoot through a resort and stepped on five. Although local hospitals carried an antivenin, she didn't seek treatment until she returned home--a mistake that cost her her life. (credit:Flickr/Terra Vermelha)
Biting midge(03 of10)
Open Image ModalCulicoides spp. Look out for it in: Everywhere.Why you should fear it: Also called no-see-ums, biting midges are a serious annoyance in the Scottish Highlands--so much so that tourists check the Biting Midge Forecast before heading out for a round of golf or a trek to a distillery. In Brazil and around the Amazon, they transmit Oropouche fever.Notorious victim: According to a community study, the biting midge broke up marriages in Hervey Bay, Australia, presumably because couples were forced to spend more time indoors together.
Paederus beetle (04 of10)
Open Image ModalPaederus sp. Look out for it in: Most of the world. Why you should fear it: The beetle lands on the skin but doesn't bite. People tend to want to slap it, which releases a nasty poison called pederin that causes horrible blisters and welts.Notorious victim: Our troops stationed in Iraq. The beetles tend to swarm around the bright lights at military bases.
Asian giant hornet(05 of10)
Open Image ModalVespa mandarina japonica Look out for it in: Japan, China, Taiwan, KoreaWhy you should fear it: Stings deliver a powerful neurotoxin that could be fatal.Notorious victim: Dr. Masato Ono, the world's leading expert on the giant hornet, said the sting felt like "a hot nail through my leg."
Pork tapeworm(06 of10)
Open Image ModalTaenia solium Look out for it in: South America, Africa, Asia, and parts of Europe and North AmericaWhy you should fear it: While modern livestock management here at home has practically eliminated tapeworm-infested pork, the tapeworm eggs can be spread directly from one infected person to another. How? Let's just say that it's really, really important to wash hands after going to the bathroom-- and leave it at that.Notorious victim: A woman in Arizona went into surgery thinking she had a brain tumor, and woke up later to learn that the cause of her problems had been a tapeworm, not a tumor. (credit:Flickr/kat m research)
Deer tick (07 of10)
Open Image ModalIxodes scapularis Look out for it in: Eastern United States (other species that transmit Lyme are found in the West and in Europe)Why you should fear it: The nymphs transmit the miserable and difficult-to-treat Lyme diseaseNotorious victim: Polly Murray, a resident of Lyme, Connecticut, battled the disease for decades and led the fight to get it properly identified, diagnosed, and treated.
Chigoe flea(08 of10)
Open Image ModalTunga penetrans Look out for it in: Tropical beaches in Latin America, the Caribbean, India, and Africa.Why you should fear it: Tiny fleas burrow under toenails and lay eggs, creating awful sores and possible infectionNotorious victim: Members of Christopher Columbus' crew were made so miserable by chigoe fleas that they cut off their own toes to get rid of the bugs.
Scorpion (09 of10)
Open Image ModalCentruroides sp. Look out for it in: Southern United States, Central and South AmericaWhy you should fear it: The venom can cause severe pain, difficulty breathing, and can be fatal to small children.Notorious victim: A little boy vacationing with his family in Mexico stepped on a scorpion in his shoe. He was flown to a hospital in San Diego, placed on life support, and did survive. (credit:Flickr/Furryscaly)
Bed bugs(10 of10)
Open Image ModalCimex lectulariusLook out for it in: Your bedWhy you should fear it: After hearing about all these other nasty creatures, you aren't still worried about bed bugs, are you? Bed bugs may be annoying, but they are not known to transmit disease. They may cause a dreadful allergic reaction, but you'll survive. Bed bugs have always been around; overuse of toxic pesticides drove them away for a few decades, but fortunately, we now realize that the chemicals were far more dangerous than the bugs.Notorious victim: You.