There are many questions that a person might consider when moving to a new city. How’s the local economy? How good are the local schools? Is there a decent public transport system, or will I be spending all my time stuck in my car?

One of the questions you’re less likely to consider is, “If I pick someone up in a bar, how likely am I to end up with a sexually transmitted infection for my troubles?”

What’s even less likely, once you’ve decided that you want to know the answer to this question, is that you’ll turn to a company who provides credit checks for landlords to get it.

But luckily, in these days of open data and viral marketing, one American tenant referencing firm has taken it upon themselves to assist our sexually liberated rolling stone.

The Centre for Disease Control collects data on the incidence of syphilis, gonorrhoea and chlamydia in every county of the United States. (Herpes data, sadly, is not available.) RentApplication.com took that data and combined it with population figures to measure rates of incidence per 100,000 people – excluding rural counties, where low populations would produce misleading statistical outliers.

The result was this map:

This map about STD statistics was created and produced by RentApplication.com.

One trend immediately leaps out at you: the southern half of the US seems to be a lot more STI-y than the north.

That said, Alaska has this going on, so:

The fact STIs are more prevalent in the lower half of the country is borne out when you look at the ten most, er, diseased cities in the US. No fewer than eight of them are in the south. Neither of the others – Philadelphia or St Louis, Missouri – are that far from the border.

Here’s the top 10, with the incidence of STDs per 100,000 population.

  1. Montgomery, AL; 1899.20
  2. St Louis, MO; 1867.54
  3. West Memphis, AR; 1717.29
  4. Philadelphia, PA; 1689.77
  5. Norfolk, VA; 1632.74
  6. Baltimore, MD; 1630.98      
  7. Richmond, VA; 1544.39
  8. New Orleans, LA; 1520.37
  9. Killeen, TX; 1512.83
  10. Fayetteville, NC; 1489.2

There’s another less obvious pattern here. Some of the cities in the top 10 are pretty obscure – had you ever heard of Killeen, Texas? We hadn’t. But three of the less known cities on this list have something in common.

Killeen (pop. 128,000) is the site of the Fort Hood US army base (pop. 53,000). Similarly, Fayetteville (pop. 204,000) is the site of Fort Bragg (pop. 40,000), while Norfolk is the site of the Norfolk Naval Base. All three of these are comfortably within the top 10 of the largest military bases on American soil.

We’re trying to be delicate about this, but… what on earth is going on in the US military? Jesus, guys, use protection.

One question remains: why? Or to be more specific, why would a company whose business involves checking up on tenants on behalf of landlords choose to investigate this?

Here’s what a spokesperson told us:

Anything that has to do with cities, states, locations, renting, etc. is fair game on our blog. But really what I’ve discovered is there’s a ton of really fascinating data out there, paid for by taxes, that is buried in PDFs, Excel files, or just presented in a boring way.

So any time we find something worthy enough we’re gonna build a map out of it. And, of course, sex always sells.

Our kind of people.