Tick-Borne & Mosquito-Borne Infections

These infections travel by bite. Ticks and mosquitoes inject the pathogen directly past your skin's defenses, which is why a creature smaller than a sesame seed can transmit diseases that change a life. Two close cousins listed below are carried by other biting insects rather than by ticks or mosquitoes — leishmaniasis by the sandfly and Chagas disease by the triatomine "kissing bug" — but they belong here because the prevention logic is identical. Prevention — repellent, tick checks, drained standing water — is worth more here than in any other group.

• Lyme Disease — The deer-tick spirochete: bull's-eye rash, and the chronic-symptoms debate
• Anaplasmosis — A tick-borne bacterium that attacks white blood cells
• Babesiosis — A malaria-like red-cell parasite from the same ticks as Lyme
• Ehrlichiosis — The lone-star tick's flu-like bacterial illness
• Rocky Mountain Spotted Fever — The most dangerous U.S. tick disease; hours matter
• Colorado Tick Fever — A biphasic mountain-west viral fever
• Powassan Virus — The rare tick virus transmitted in minutes, not hours
• Tick-Borne Encephalitis — The European and Asian tick brain infection
• Tularemia — "Rabbit fever" from ticks, animals, and even lawnmowers
• Malaria — The mosquito-borne parasite that has shaped human history
• Dengue Fever — "Breakbone fever," and why a second infection is worse than the first
• Chikungunya — The mosquito virus named for its bent-over joint pain
• West Nile Virus — The most common U.S. mosquito-borne disease
• Yellow Fever — The jaundice-and-fever virus with a century-old vaccine
• Zika Virus — Mild for adults, a serious threat to a developing fetus
• Leishmaniasis — The sandfly parasite behind non-healing skin sores
• Chagas Disease — The kissing-bug parasite that can quietly damage the heart for decades