Implicating suburban sprawl in the spread of ticks and pathogens

As new tick-borne illnesses spread, sprawl is part of the problem:

But as climate change, suburban sprawl, and increased international travel are putting more ticks and the pathogens they carry in the paths of humans, what’s becoming more urgently apparent is how the US’s tick monitoring systems are not keeping pace.

“It’s really a patchwork in terms of the effort that different areas are putting into surveillance,” says Becky Eisen, a tick biologist with CDC’s Division of Vector-Borne diseases. The federal public health agency maintains national maps of the ranges of different tick species, but they’re extrapolated from scattered data collected in large part by academic researchers. Only a few states, mostly in the Northeast, have dedicated tick surveillance and control programs. That leaves large parts of the country in a data blackout.

To help address that problem the CDC is funding an effort to identify the most urgent gaps in surveillance. It has also begun publishing guidance documents for public health departments on how to collect ticks and test them for diseases, to encourage more consistent data collection across different states and counties.

In an ideal world, says Eisen, every county in the US would send a few well-protected people out into fields and forests every spring and summer, setting traps or dragging a white flannel sheet between them to collect all the ticks making their homes in the grasses and underbrush. Their precise numbers, locations, and species would be recorded so that later on when they get ground up and tested, that DNA would paint a national picture of risk for exposure to every tick-borne pathogen in America. But she recognizes that would be incredibly labor-intensive, and with only so many public funding dollars to go around each year, there are always competing priorities.“But from a research perspective, that’s the kind of repeatable, consistent data we’d really want,” says Eisen. “That would be the dream.”

While there is little direct discussion of sprawl, I wonder if there are two problems at play.

First, sprawl puts more people in interaction with more natural settings. As metropolitan areas expand, more residents end up in higher densities in areas that previously had experienced limited human residence. More people at the wildland urban interface could potentially lead to more problems in both directions: humans can pick up diseases while nature can be negatively impacted by more people.

Second, increasing sprawl means more data needs to be collected as more people are at possible threat. Metropolitan areas (metropolitan statistical areas according to the Census Bureau) typically expand county by county as outer counties increase in population and have more ties to the rest of the region. Since many metropolitan regions expand in circles, adding more counties at the edges could significantly increase the number of counties that need monitoring. And as the article ends with, finding money to do all that data collection and analysis is difficult.

Making a horror film about illnesses carried by ticks would take some work to make interesting but these sorts of hidden and minimally problematic in terms of number of suburbanites at this point issues could cause a lot of anxiety.

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