Here’s a question that I get commonly: “What do I do to an outdoor area that might have been contaminated by a dog with parvovirus?

There’s not a lot of research to back anything up, but understanding the virus and some basic principles helps us come up with some reasonable recommendations.

Parvovirus is…

  • Highly tolerant of environmental exposure, disinfectants and other things that kill most viruses.
  • Shed in potentially massive amounts in the feces of sick animals, but also potentially by some healthy animals.
  • The cause of a potentially fatal disease.
  • A pathogen against which we have effective vaccines.
  • Really only a concern for unvaccinated (or inadequately vaccinated) dogs.

There’s definitely cause for concern if a puppy with parvo infection has passed diarrhea outside. We can assume there’s lots of virus there, and that the virus is going to be able to survive there for some time. We don’t know how long, and it will certainly vary with environmental conditions (e.g. temperature, pH of the soil, humidity, sunlight), but it’s safe to assume that it will be a fairly long time in most situations.

So, what do we do?

  • Disinfection of outdoor surfaces is pretty futile. Disinfectants don’t work well in the presence of organic debris (dirt), so pouring disinfectants on grass or gravel will not likely do much (except put a lot of disinfectant residue into the environment). Unless it’s happened on a surface like concrete or asphalt (both of which can still be hard to adequately disinfect because they are porous), leave the bleach bottle in the cupboard.
  • Removing feces is a good first step. This actually removes the vast majority of virus that has been passed. It might require using a shovel to get rid of some of the diarrhea-soaked grass or soil, but removing as much of the visible contamination as possible is key.
  • Restricting access to the area can’t hurt, when it’s feasible. That doesn’t mean cordoning it off and keeping everyone away. The focus should be to keep young, unvaccinated or incompletely vaccinated dogs (and dogs that have contact with those dogs) away from the area.
  • Raking the site can help turn over the substrate (e.g. dirt, soil, gravel) and get more exposure to UV light. Sunlight is our best outdoor disinfectant, and raking can help expose virus particles that are hidden away.

As always, prevention is better than cure. Preventing these situations is ideal, but admittedly not always possible. Things that can help include:

  • Making sure all puppies are properly vaccinated.
  • Keeping unvaccinated puppies away from high dog-traffic areas.
  • Keeping sick animals away from public areas.
  • Promptly picking up feces from any dog, healthy or not.