Diseases of...The FUTURE!
Every era has its diseases. The medieval world was hit by wave after wave of bubonic plague, the most famous of which killed half or more of the entire population of Europe. During the American colonial period, the Native Americans were ravaged by smallpox, transmitted to them (sometimes purposefully) by a bunch of filthy, dirty Europeans. The first half of the 20th century was scourged by polio, killing and crippling children by the thousands before Jonas Salk finished development on his killed-virus polio vaccine in 1955.
Shortly thereafter it was definitively proven that smoking is really, really bad for you. The 1980s and 90s were all about AIDS as a frightened world tried to figure out this terrifying new disease. It attacks your immune system! That's totally not fair! In the 21st century we've already dealt with epidemics and hysteria surrounding SARS, bird flu, swine flu, Ebola, and, thanks to the types of people who really believe an iron lung is better than a vaccine, the freakin' measles.
Today, though, I'm going to use my powers of Super Science to look into the future. As Star Trek: The Next Generation has amply demonstrated, cure some diseases and the universe will just invent new ones. As we stand on the cusp of vaccines for Ebola and HIV with cancer outcomes at an all-time high it's about time for the cosmos to throw us a curveball. I'm here today to catch that curveball. Don't say I didn't warn you.
With pulmonologist admissions on the rise in industrialized nations the CDC and WHO begin to look into possible new causes of lung problems in an era where only teenagers and really awful trailer people still smoke cigarettes. As boring white collar workers succumb to coughing fits, asthma attacks and, in severe cases, cancer and emphysema, doctors and scientists identify a horrifying new disease: Office Lung. Turns out that all those toner fumes from copiers and laser printers weren't so harmless after all. Should have gone paperless, folks. Should have saved those trees.
Treatment: Inhaled corticosteroids in minor cases, with a universal recommendation of getting a job that doesn't suck
The wealth inequality gap grows and more and more people find themselves turning to the lottery in a vain attempt to better their economic situation. In order to stem the rising tide of counterfeit tickets, lotteries begin to print with a new, special ink formula. The ink absorbs easily into human skin and plays havoc with hormone levels resulting in a terrible disorder known as Powerballs. Biologically male lotto players find themselves flying into blind rages and developing horrible bacne, eventually suffering from severe testicular pain followed by shrinkage; oddly, biological females seem immune. Big Lotto predictably denies fault, claiming "Dudes are just like that, yo."
Treatment: Only buying a ticket when the jackpot is, like, really huge.
The Mercury Militia has succeeded beyond their wildest dreams: enormous pockets of affluent, urban white people have succumbed to the belief that vaccines are worse than selling your soul to multiple devils. Localized epidemics spring up around the United States with an enormous constellation of symptoms, referred to as "Literally all of them, you guys," in the NEJM by Proctor et al, September 2038. Due to the victims' apparent lack of any immunity to anything, ever, the disease is referred to as Naughtism. Broad spectrum antibiotics and cutting-edge antivirals are shipped out en masse but see only limited success. The parents of the victims claim that it's still better than getting those gross, dirty vaccines.
Treatment: Not being the child of total morons
Arctic and antarctic ice is nearly gone and sea levels have risen catastrophically. Global climate change is causing extreme weather patterns all over the globe. Droughts, blizzards, tornadoes, heat waves, and more scour the Earth from pole. Technology adapts to the issues, creating a new normal for almost everyone on the planet. For a few, however, climate change was all a conspiracy all along. It never actually happened, and they go to great lengths to prove it. The Florida Keys are home to a colony of newly aquatic humans, having looted historic dive equipment from the History of Diving Museum in Islamorada. When reached for comment they profess ignorance of the water around them. All across the world, but mostly in the United States, people wear shorts during ice storms and whine about how chilly it is during heat waves. After many years of psychological study, Schizoveritas, a violent split from obvious truth, is included in the DSM-VII.
Treatment: None known; all attempts at treatment are labeled as "part of the conspiracy"
Genetic technology is a part of everyday life and genetic modification has led to a world full of foods that are nutritious, delicious, and bountiful. A McDonald's cheeseburger now has fewer calories than a salad used to and supplies all of the necessary vitamins, minerals, and amino acids (and tastes better than ever, too). Most people jump on the GMO bandwagon and quickly become the healthiest humans in history. Many, though, maintain a vocal resistance to the new technology and continue eating "natural"; you know, food that's only been genetically modified by mutation breeding using chemistry or radiation. They aren't unhealthy by modern standards, but compared to the new Übermenschen they're sickly and weak. The condition is dubbed Antiquitarianism, which becomes confusing in 2123 when a small fraction of people begin eating ancient Greek and Roman pottery.
Treatment: None recommended, but they are missing out on some totally boss ribeyes (this applies to both forms of Antiquitarianism)
Undoubtedly the future is rife with even more diseases, stranger and worse than those catalogued here. Even Super Science, however, can only see so far. The future is wild and wooly, with nature and our own lifestyles ready to smack us upside the head with new maladies at the drop of a hat. Forewarned is forearmed, though, so hopefully I've been some small help to you and your descendants.