Tick-Borne Illness Has Tripled, but the CDC Refuses to Blame Climate Change

We count on the Centers for Disease Control and Prevention (CDC) to look out for our public health interests — whether responding to outbreaks or identifying emerging threats. These should be nonpartisan activities, but there are signs that the Trump administration’s antipathy to climate science is creeping into CDC policy. And that’s bad news for all of us — including climate change skeptics.

That point was made clear in a recent CDC report about the rise of tick-borne illnesses. While many people associate ticks with Lyme disease, they can also cause Rocky Mountain Spotted Fever, dengue, Zika, West Nile and a number of other illnesses.

Epidemiological evidence suggests that some tick-borne illnesses are becoming more common and spreading out of their traditional range. One reason for the shift is environmental pressure, as development expands into former wilderness areas. But warming patterns are partially responsible too, making it possible for ticks to thrive further north than ever before.

These facts are pretty inescapable, but the lead author of the CDC report is dodging the question of why, exactly, the weather’s getting toastier. Instead, he’s focused on activities like “jet travel” and the unavailability of vaccines for some of these conditions. While there are definitely additional factors, climate change feels like the elephant in the room.

That hasn’t always been the case. Until pretty recently, the CDC openly acknowledged the role of climate change in thriving tick populations. The organization didn’t lay the blame entirely at the feet of climate change, but it did acknowledge it as a contributing factor. That’s important, because without openly discussing the topic, it’s very hard to control for climate change’s role in the spread of disease: Saying you know it’s a problem means you can start thinking about how to combat it.

In the long term, of course, taking steps to slow the rate of climate change is important for global health. But in the short term, thinking about how rising temperatures might incubate more vectors and diseases is important — for example, health agencies can make predictions for the coming years about where infections might turn up. That could inform activities like public education and outreach, showing people how to protect themselves, and making sure that clinicians are aware of symptoms to look out for when treating patients.

With formerly rare diseases, that last point is really important. A doctor might not think to test for an illness that hasn’t been seen in an area before, or might dismiss a patient with complaints suggestive of an unusual tick-borne disease. Someone who’s aware that a disease is spreading, however, might be more proactive in patient evaluations and conversations; for instance, a patient who works out in the woods might get extra screening, or advice on avoiding insects and a warning that ticks might be active earlier in the year than they used to be.

The decision to overlook climate change in official documentation doesn’t go unnoticed. The World Health Organization acknowledges that climate change is an issue of global health concern, and the US is a member of the WHO. It doesn’t look great to have the country’s leading health agency refusing to acknowledge climate change — and it feeds the fires of climate change denial.