A new prediction says 2017 and 2018 will see major Lyme disease outbreaks in new areas. This could lead to lifelong health consequences, so where’s the vaccine?
BY THE time he had finished his walk through the woods in New York state, Rick Ostfeld was ready to declare a public health emergency. He could read the warning signs in the acorns that littered the forest floor – seeds of a chain of events that will culminate in an unprecedented outbreak of Lyme disease this year.
Since that day in 2015, Ostfeld has been publicising the coming outbreak. Thanks to a changing climate it could be one of the worst on record: the ticks that carry the disease have been found in places where it has never before been a problem – and where most people don’t know how to respond. The danger zone isn’t confined to the US: similar signs are flagging potential outbreaks in Europe. Polish researchers predict a major outbreak there in 2018.
In theory, Ostfeld’s early warning system gives public health officials a two-year window to prepare. In many other cases, this would be enough time to roll out a vaccination programme. But there is no human vaccine for Lyme disease. Why not? And what can you do to protect yourself in the meantime?
Lyme disease is the most common infection following an insect bite in the US: the Centers for Disease Control estimates that 300,000 Americans contract Lyme disease each year, calling it “a major US public health problem”. While it is easy enough to treat if caught early, we are still getting to grips with lifelong health problems that can stem from not catching it in time (see “Do I have Lyme disease?“).
This is less of a problem when Lyme is confined to a few small areas of the US, but thanks in part to warmer winters, the disease is spreading beyond its usual territory, extending across the US (see map) and into Europe and forested areas of Asia. In Europe in particular, confirmed cases have been steadily rising for 30 years – today, the World Health Organization estimates that 65,000 people get Lyme disease each year in the region. In the UK, 2000 to 3000 cases are diagnosed each year, up tenfold from 2001, estimates the UK’s National Health Service.
So how could a floor of acorns two years ago tell Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies in Millbrook, New York, that 2017 would see an outbreak of Lyme disease? It’s all down to what happens next.
A bumper crop of the seeds – “like you were walking on ball bearings” – comes along every two to five years in Millbrook. Crucially, these nutrient-packed meals swell the mouse population: “2016 was a real mouse plague of a year,” he says. And mouse plagues bring tick plagues.
Soon after hatching, young ticks start “questing” – grasping onto grasses or leaves with their hind legs and waving their forelegs, ready to hitch a ride on whatever passes by, usually a mouse.
SOURCE: Chelsea Whyte