The story of the emergence of Lyme disease now, of its rise in dozens of countries around the world and of millions made sick, must be told through the lens of a modern society living in an altered environment. In the last quarter of the 20th century, a delicate array of natural forces indisputably tipped – were tipped, more accurately – to transform Lyme disease from an organism that lingered quietly in the environment for millennia to what it is today: the substance of painful stories shared between mothers; a quandary for doctors who lack good diagnostic tests and clear direction; the object of rancour over studies that discount enduring infection while acknowledging persisting pain.
The CDC does not use the word ‘epidemic’ to describe Lyme disease. It prefers the term ‘endemic’, which it defines as the ‘constant presence and/or usual prevalence of a disease or infectious agent in a population within a geographic area’. But, surely, Lyme was not always present or prevalent. Nor is it confined within well-defined borders. The CDC’s linguistic choice is unfortunate. It serves to minimise the import of a disease that yields some 300,000 to 400,000 new cases in the US each year, is found in at least 30 countries and likely many more, and is growing precipitously around the world. Lyme disease is moving, breaking out, spreading like an epidemic.
The ticks that carry Lyme disease are, like spiders, arachnids not insects. Although they cannot fly or jump, they are, for all practical purposes, climbing mountains, crossing rivers and traversing hundreds, even thousands, of miles to set up housekeeping. These feats are documented by scientists who are ingenious at finding ways to track and count ticks. They drag white flannel sheets across leafy forest carpets, sometimes infusing them with piped-in carbon dioxide, the mammal gas that makes ticks reach up, forelegs outstretched, to snag a passing meal. They catch avian migrants infested with hitchhiking arachnids. They count ticks on the ears of trapped mice and shrews, sometimes getting bitten in the process. They dissect bird nests, reach beneath leaf litter, and scour grassy sand dunes.
In 2014, the US Environmental Protection Agency (EPA) issued a 112-page report on the future of the US in a warmer world. It began with a conclusion that had been denied, discounted and politicised in the US for decades, but at last, or perhaps for the moment at least, was accepted as true:
The Earth’s climate is changing. Temperatures are rising, snow and rainfall patterns are shifting, and more extreme climate events – like heavy rainstorms and record high temperatures – are already taking place. Scientists are highly confident that many of these observed changes can be linked to the climbing levels of carbon dioxide and other greenhouse gases in our atmosphere, which are caused by human activities.
