Can Dog Poop Make You Sick or Blind (worms, bugs + more!)?

I was invited to talk to Jason Smith from Petcorps Professional Pet Care about the dangers and public health risks associated with dog poop and ultimately answer the question “Can dog poop make you sick?”. I remember growing up that it was really common to have to avoid stepping in dog waste on the pavement or in grass verges around playing fields and parks. Thankfully things have changes and it has become more common for people to pick up after their dog.

As well as make the environment we live in more pleasant, this has also served an important role in improving both dog and human health. Not everyone though picks up as they should and in some parts of the world the risks are higher than others.

Make sure you watch this video or read the full transcript below to learn the full story!


Why should you clean up after your dog. Why shouldn’t you try and mow it up, leave it to fertilize the lawn or just let it decompose?

Anyone who has tried mowing up dog waste will know that very little gets picked up by the mower, most of it just gets smeared into the soil or just spread around a bit. Not only does this not get rid of the dog waste, it also makes it more messy and harder to then clear it up.

Moving onto the fertilizer theory, I think this comes about because cow muck can be spread as slurry by farmers or horse feces can be added to the garden to make your veges grow better. Dog poop is not the same though. They tend to have a much more acidic stool which means that it will end up burning and killing your lawn or plants, rather than helping it grow better. If just left wherever your dog decides to go toilet, it will also remain a potential health hazard.

The same is true if you are just leaving the dog poop to decompose. Dog waste is biodegradable but it can take an awfully long time to fully decompose. In certain environments this might mean it takes a year or even longer. Not only it this unsightly and dirty, again it also means that you are leaving a potential hazard and health risk in the environment.

Another consideration is that it might be illegal not to clean up after your dog. Depending on where you live, there are quite rightly laws in place that you should always pick up after your dog, with some hefty fines if you fail to comply. DNA testing can even be used to prove it was your dog who was responsible for leaving a mess.

What are the health risks of dog poop to people and dogs?

This is a great question because I think a lot of the time we think of dog poop as unsightly and disgusting but actually don’t think of the health risks it can present to us as well as our pets.

So dog poop can contain bacteria like Salmonella, Campylobacter and E.coli. It can contain viruses like Parvovirus. Protozoa like Giardia. Parasites like roundworm and hookworm. It’s quite a long list of potential health risks that can infect dogs. They are also what we call zoonotic diseases which means they can be passed from animals to people.

Let’s talk about dogs to start with. All of these various hazards are transmissible from one dog to another. Not only that, they can persist in the environment for a really long time, many years in some cases. There are several diseases that you might see as a result. The most obvious is intestinal upset with diarrhea or vomiting or both. Something like parvovirus especially can result in disease that is so serious it very often ends up being fatal, especially in young puppies who contract the disease.

Something like worms might go undetected for some time before causing problems like a reduction in the number of red blood cells in the blood. Worms can even result in potentially fatal intestinal obstruction or something known as intussusception where the intestine telescopes into itself.

The other clear issue with spreading these diseases to other dogs is that they can then spread them even more and create an even greater health risk to other dogs and people.

So these health hazards, as you might have guessed, can also be spread to people. Contracting Salmonella, Campylobacter, E.coli or Giardia is no fun at all causing vomiting, diarrhea and severe stomach cramps. In someone who is young, old or otherwise unwell these diseases can be very serious, even potentially fatal without hospitalization and re-hydration therapy.

Worms too can infect people which is a disgusting thought. Now you might think that they will only cause problems within the intestines, and they do cause problems here but they can affect other parts of the body too. If they stay in the intestine then they can cause diarrhea, cramping, nausea, vomiting, fatigue, fever and they can even cause intestinal obstruction, especially in children who have narrower guts.

Hookworm can also cause blood loss anemia and iron deficiency as these worms feed on your blood!

Apart from intestinal damage and problems, worms also cause a problem in people because of their life-cycle. What happens is the worm larvae enter the bloodstream and generally head to the lungs where they mature. Once developed they are coughed up and swallowed which is how they then reach the intestine.

From this you can understand then why worm infection can also result in symptoms like wheezing, coughing, chest pain and even pneumonia.

Even more problems can develop when the migration of the larvae goes wrong. Severe rashes and inflamed tracts can develop in the case of hookworm especially as they migrate through the skin (cutaneous larval migrans). Roundworms are more likely to migrate through different body organs (visceral larval migrans) and even the eye (ocular larval migrans). The problems are more likely in children and can result in organ damage and even loss of some vision or blindness if left untreated.

So yes, dog poop can make you go blind!

Thankfully these severe complications are pretty rare but when the significance of disease is so extreme it falls on all of us to reduce the risk wherever possible.

How do people get infected with hookworm and roundworm. Is there anything we can do to prevent infection?

Absolutely, so hookworm is contracted by your skin coming into contact with soil infected with hookworm larvae. This is generally when you walk around barefoot but could equally be when you lie on the ground in the sun over the summer or play in the dirt if you’re a child, or even garden without gloves.

The hookworm larvae actually penetrate the skin and gain access to the blood vessels that way as I’ve already discussed. It is also because of this penetration that you can get the abnormal migration within the skin I mentioned.

With roundworm, infection is transmitted to people by handling contaminated soil which then get into their mouth. This is why children are most at risk.

It’s important to mention at this stage that the worm larvae aren’t immediately infectious once passed out in a dog’s stool. It takes a week or two depending on conditions for the worm larvae to mature and so you won’t necessarily notice and dog waste in the area if it’s been picked up or washed away. The longer the dog waste is around though, the more contamination of the area will be present.

Knowing this is how we contract hookworm and roundworm we can think about how to prevent infection and we can do this in a number of ways:

  • Treat our dogs with worming medication regularly

  • Pick up your dog's waste straight away

  • Don't walk around barefoot if hookworm is present in your region

  • Practice good hand hygiene, especially before eating

Can dog poop contaminate streams, lakes and other waterways?

Absolutely, the bacteria and Giardia can be washed into waterways where they will remain infectious. If there is a period of heavy rain and there is lots of dog waste near a waterway, or in a stormwater runoff, then a really high level of these infectious organisms can be washed into the waterway. This is especially a problem when the water runs of into bodies of water used for recreation as there will be a risk of infection to people swimming, sailing, fishing or using the water in any other way.

Of course there might be other pollutants you would be more worried about if you live in a city but dog waste is a definite problem and might be the only concern in more rural areas with waterways running into recreational lakes.

If the contaminated water gets into the groundwater which is then extracted in wells that are untreated the same could happen. People could become sick due to water contamination.

What do you use to clean up after your dog? Do you also clean up after them when they go in the garden or leave it for a weekly “poo patrol”? Let me know!

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