The Polar Vortex that kept so many of us indoors for months has finally retreated. This can only mean 1 thing: mosquito season. As humans spend more time outside, they are exposed to illness carried by mosquitoes and ticks and there are some not-so-fun new ones to learn about. First the oldies but goodies.
Lyme disease is the best-known tick-borne disease in the U.S. It is endemic to the Northeast, parts of the Upper Midwest, and some parts of the Pacific Northwest. It causes a characteristic “bulleye” rash called erythema migrans, and if untreated can lead to fever, joint pains, and occasionally more serious symptoms. It is very easily treated with antibiotics. Despite the hype coming from some patients and doctors, once Lyme is treated it is cured. There is no such thing as “chronic Lyme disease”.
Mosquito bites are a lot more common than tick bites and can cause some remarkably horrid diseases. The worst of these is malaria which kills about 627,000 people every year around the world. Thankfully, it’s quite rare in the U.S. (but it wasn’t always). The biggest risk to Americans is with travel to endemic areas. Malaria classically causes very high relapsing fevers, and any fevers after travel to a malarial area should be evaluated by a doctor.
Gaining a larger foothold in North America is Dengue fever, also known as “breakbone fever” for the tremendous pain it causes.
Dengue is uncommon in the continental US, but is very common in the Caribbean, including Puerto Rico. It causes fever and tremendous joint and muscle pain, but usually no lasting damage. It is generally confined to tropical and sub-tropical regions, but global travel and climate change are putting the continental US at greater risk. In 2009 there was an outbreak in Key West, Fla. that was not imported from abroad.
The latest player, and the one with the best name, is chikungunya. This mosquito-borne virus has recently made its way to the western hemisphere and is becoming a significant problem in the Caribbean. So far there haven’t been an cases transmitted within the continental U.S., but this could easily change as travelers have returned with the disease, and there are native mosquitoes that can carry it. “Chick” is very much like dengue, the name coming from a Makonde word meaning “it bends up”, presumably referring to the contortions of pain suffered by its victims.
The good news is that all of these diseases are preventable. Public health measures can eliminate or treat standing water where mosquitoes breed, and individuals can cover up, use DEET-based insect repellent, and limit exposed skin, especially at dawn and dusk when many mosquitoes prefer to feed. (Ticks are a bit trickier, but they can’t bite through clothes, so tuck in those pant-legs).
Your risk of getting a bug-borne illness in the U.S. is still quite low, but if you want to avoid ruining your day, check your local health department’s website for updates on nearby outbreaks and prevention measures.
Peter A. Lipson, ACP Member, is a practicing internist and teaching physician in Southeast Michigan. After graduating from Rush Medical College in Chicago, he completed his internal medicine residency at Northwestern Memorial Hospital. This post first appeared at his blog at Forbes. His blog, which has been around in various forms since 2007, offers "musings on the intersection of science, medicine, and culture." His writing focuses on the difference between science-based medicine and "everything else," but also speaks to the day-to-day practice of medicine, fatherhood, and whatever else migrates from his head to his keyboard.