Here’s a question I get surprisingly often.

I found a dead raccoon (or raccoon poop) in my pool and I’m freaking out about raccoon roundworms. What should I do?

The raccoon roundworm, Baylisascaris procyonis, is certainly a parasite of concern, but it’s also one that often leads to over-reaction and panic. While it can cause severe disease in people, infectious are really rare, and almost always associated with ingestion of a pretty reasonable amount of raccoon poop. A large percentage of raccoons carry the parasite in their intestinal tracts so there’s really widespread opportunity for exposure, but the rarity of disease shows how low level and casual contact with the parasite’s eggs likely pose little to no risk to most people.

The concern with a dead raccoon or raccoon poop in a pool is that there will likely be roundworm eggs (the infectious form of the parasite) in the water. The eggs survive very well in the environment, so they persist for a long time outside the host, and they aren’t destroyed by either chlorine or salt water.

However, in a pool we have two important protective mechanisms: dilution and filtration.

Although we have no hard data, I’d say the odds of getting infected with Baylisascaris from pool exposure are pretty much zero (as long as you don’t ingest floating piles of feces…). That said, it’s still reasonable to take some precautions to remove as much contamination from the pool as possible.

The US CDC has quite a detailed guidance specifically for cleaning pools potentially contaminated with raccoon feces. The guidance says to test the raccoon/raccoon feces for Baylisascaris, and clean the pool.

  • Since the response to a positive or negative test is the same (clean the pool), testing seems unhelpful. It adds cost, hassle and a time delay, and with a negative, I still wouldn’t rule out that the critter was infected since testing isn’t 100% sensitive. So, I’d skip the testing and just assume the critter was positive.

For cleaning the pool, they provide two options:

Option 1:

  • Filter the pool for a minimum of 24 hours and then backwash the pool filter.
  • Put on disposable gloves to replace the material doing the filtering (if possible). Double bag the discarded material in plastic garbage bags. Remove gloves and place them in the garbage bags. Wash your hands thoroughly with soap and water afterwards.

Option 2:

  • Backwash the pool filter.
  • Drain and hose down the pool.
  • Put on disposable gloves to replace the material doing the filtering (if possible). Double bag the discarded material in plastic garbage bags. Remove gloves and place them in the garbage bags. Wash your hands thoroughly with soap and water afterwards.
  • Refill the pool.

I think changing the filter medium isn’t very high yield, and depending on the filter type, it can be a pain. They include an “if possible” disclaimer, but I’d go farther and say “don’t bother unless you’re really worried.” The odds of a pool filter being a source of infection for this parasite, from my perspective, are basically zero (and if there’s a risk to worry about, it’s probably greater from handling the filter than leaving it in place).

Anyway, it’s fine to take that approach, but the main steps that are both practical and effective are:

  • Remove any visible feces (rinse whatever was used to do so after).
  • If there was a chance of contamination of hands while cleaning, wash hands thoroughly.
  • Keep people out of the water for 24 hours with the filter running.
  • Don’t stress about it.

While you’re at it, it never hurts to take a look at your yard to identify and eliminate anything that might be encouraging raccoons to visit (e.g. accessible food sources or garbage).