A Bug Problem Centuries in the Making

You are not imagining it. The bugs really are getting worse. And the reasons why stretch back further than you might expect — to colonial-era land use decisions, the abundance of acorns on oak trees, and a warming climate that is steadily rewriting the rules of where dangerous insects can survive and thrive.

From a disease standpoint, it’s undeniable that bugs are posing an ever-larger problem. Reported cases of vector-borne diseases doubled between 2005 and 2019, according to CDC data, and researchers have discovered 10 new pathogens in the previous 17 years. That is not a blip. That is a trend — and it is accelerating.

The Acorn Connection You Never Saw Coming

One of the stranger links in the chain of tick proliferation involves something most people crunch underfoot without a second thought. The best predictor of how many ticks are likely to be around each year is how many white-footed mice were present the previous summer. And the best predictor of mouse numbers is how many acorns fell from oak trees the previous fall. Lots of acorns one year means lots of mice the next, which gives baby ticks a greater chance of biting a mouse and surviving long enough to bite us.

That progression led to a particularly bad year in some regions in 2025. Findings from the field in places like Connecticut support CDC data on higher-than-usual emergency department visits for tick bites. The numbers seen in 2026, both in submissions of ticks to be tested for pathogens and in field sweeps, are “substantially higher” than last year.

New Invaders and Old Threats Expanding Their Turf

Houseflies thrive in warmer temperatures, and they are not just annoying — they are mechanical vectors of disease. They walk through garbage and then across countertops, leaving salmonella and other pathogens behind in their tiny footprints. Meanwhile, a far more alarming newcomer has been quietly establishing itself. Longhorned ticks first appeared on American shores in 2017 — and they can clone themselves. Female ticks produce thousands of self-copies; on the extremely rare occasions males are produced, it is thought to be by mistake.

Aedes aegypti mosquitoes — carriers of dengue, Zika, and yellow fever — are estimated to be spreading northward in the US at a rate of about 150 miles per year, according to research from the Yale School of the Environment. Entomologists predicted an especially buggy 2026, with a mild, damp spring boosting mosquito populations early in states from Texas to Mississippi, and tropical storms triggering mosquito surges from standing water in the Southeast.

Land, Deer, Suburbs — and What Comes Next

Climate change gets a lot of the blame, but the story is more complicated. Climate plays a role, but so do factors related to landscape changes in the United States since the turn of the century. Deer — nearly wiped out in certain regions by deforestation and over-hunting — don’t carry Lyme-causing bacteria, but they do carry ticks around. White-footed mice, which do carry the culprit bacteria, thrive in areas disturbed by people — and people are increasingly good at disturbing things, through means like suburbanization.

One Connecticut tick expert, Dr. Goudarz Molaei, who has been tracking a rise in tick numbers and disease cases, called the current situation “a tip of the iceberg.” He warned that ticks are “mostly limited to the coastal areas” now, but that “in a few years, as the warming pattern continues, these will move from coastal regions inland.” That warning should land with urgency for anyone who spends time outdoors — which, in summer, is most of us. The bugs are not just a nuisance anymore. They are a public health story, and it is only getting started.