How to avoid getting toxoplasmosis from your indoor cat's faeces

I believe that the disease toxoplasmosis is somewhat underrated by many cat caregivers probably because the symptoms in people and cats are often all but invisible. But many are asymptomatically infected. 

The 24-hour window

Toxoplasmosis is one of the most prominent detriments to the overwhelming benefits of living with a domestic cat companion. A lot has been spoken about the danger of getting toxoplasmosis from your cat's faeces. This comes from the fact that domestic cats being the primary vector of the disease shed toxoplasma gondii oocysts in faeces for a short period of time after they been exposed to it.

Toxoplasma gondii oocyst

Although this is a one-off event covering a 2-week period it does happen, which is why domestic cats are heavily criticised by people who dislike cats. But the CDC in America tells us something very important about the shedding of oocysts in cat faeces and it is this. They say that they are only infective (i.e. capable of passing on the disease) after they've been in the environment i.e. outside of the domestic cat for more than one day and between 1-5 days.

Therefore, there is a window between the moment a domestic cat defecates in the cat litter to 24 hours later when their faeces are not infective in terms of the toxoplasma gondii protozoan. That being accepted, if a cat owner cleans out the litter tray every day within 24 hours of it being used by their cat, they will not be exposed to infective toxoplasma oocysts.

This is provided they have been careful in cleaning the litter tray the day before and ensured that no faeces remain. To recap, if a cat caregiver ensures that they thoroughly clean the litter tray daily (on a strict basis) they should pretty well eliminate the possibility of being infected by this zoonotic disease through contact with a cat's faeces. I think that is quite an important statement because it deals effectively with this mode of transmission which has been discussed a lot on the Internet.

No raw treats or unpasteurised milk

And what I said above can be supported by this further information. If you only provide an indoor cat with commercially manufactured cat food there is no possibility that they can ingest the protozoan in food. However, if you feed them raw pork or beef or unpasteurised dairy products which might contain the toxoplasma organism, and they might contract the disease. So, there's two sides to this preventative process. You don't let your cat ingest the protozoan and you prevent them transmitting the protozoan through their faeces as described above. Tackled this way I don't perceive a problem with this disease for a family who looks after a full-time indoor cat.

Clean it every 24 hours for indoor cats to avoid a toxoplasma gondii infection from cat feces. Photo: Warren Photographic.

Children exposed to cats and mental health when adults

Today, I also read about a study which stated that, on my interpretation, children exposed to the family's domestic cat are 8 percent more likely to suffer from some sort of mental health problem when they are an adult compared to those adults who were not exposed to a domestic cat when there are children. 

In round terms, what the study concluded is that due to the possibility of being infected with toxoplasmosis when they are children, they are more likely to have mental health problems because of the presence of this disease in the brain when they are adults. It's a relatively small added risk but it is, at 8%, recognisable.

Please click on this link when you have finished reading this page for a cross-post on this topic.

We don't need to believe in the study but we should at least take note of it. Clearly, the tip about the cat litter that I mention above is significant in eliminating this added risk. Particularly as it is probably not unlikely that children will be assisting the household by cleaning out the cat litter tray. 

If they follow the method that I have mentioned it should all but eliminate the risk and place children with cats on a par with other children who don't come into contact with a cat in terms of mental health when they are adults.

Hawaiian government procrastinates about how to deal with their 'cat problem'

US News today reports on a male Hawaiian monk seal dying after a five-week battle with toxoplasmosis. It has prompted another discussion about how Hawaii should deal with both domestic and feral cats. The argument is that the toxoplasma oocysts which are shed in both feral and domestic cat faeces (once) somehow make their way to the sea where monk seals ingest the oocysts and become infected with toxoplasmosis.

Comparison of size of Hawaii 4 main islands with UK. Image: MikeB from mylifeelsewhere.com.

They tried to save this seal but, as mentioned, it died. The seal, known as RW22, was treated at the Marine Mammal Center. They called on cat owners to keep their pets indoors and to dispose of faeces in cat litter in the trash. It's another instance of where putting cat litter down the toilet is a bad idea. It has to going to landfill. However, I guess oocysts can still make it to the sea from landfill under certain circumstances.

But the point of this article is that in 2016, five years ago, there was a report of eight monk seals dying for the same reason. The symptoms in the infected seals vary but they included lesions in the brain, adrenal glands, diaphragm, lymph nodes and spleen. In the case of RW22, the seal showed signs of partial facial nerve paralysis and a corneal ulcer which they believed were symptoms of toxoplasmosis.

So there is an ongoing problem if the experts are right in Hawaii of feral and domestic cat faeces making their way to the ocean around the four main islands. And little or nothing has been done about it, it seems to me, over the intervening five years and I presume longer.

They are constantly moaning about a feral cat problem on Hawaii with the cats attacking precious Hawaiian birds. There's been report about that as well. They appear to be scratching their heads about how to deal with the problem.

I think the real problem is a lack of leadership in the Hawaiian government. This is combined with a lack of commitment in dealing with this problem.

One website louisegund.com tells me that there are TNR programs on Hawaii run by volunteers which is very normal but that the government opposes them. They don't think it works. That too is quite normal. Some people support TNR and others disagree with it. It is too slow for some and returning the cats to where they came from doesn't make sense to some people.

However, the 4 Hawaiian main islands are about 1/15 the size of the UK. The point is that it is not a huge geographic area and it makes me believe that the government could successfully operate widespread TNR on the three smaller islands to start off with. 

They could support the volunteers and formalise TNR programs to make them more widespread and therefore more effective. Currently it is the only way to deal with feral cats humanely. You have to deal with the cats humanely because people put them there. And killing them is ineffective due to the vacuum effect. 

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In parallel with that there should be more determined approach to managing domestic cat ownership and raising standards. You'll find quite a lot of discussion in other parts of the world on obligatory micro-chipping, spaying and neutering and on occasions curfews either during the night to keep the cats inside or even mandating keeping cats within the bounds of the owner's property full-time. 

I'm not saying that that is the way to go but with a manageable human population size it may be feasible to operate obligatory registration of domestic cats and from there to make micro-chipping and spaying and neutering obligatory as well. The hard part is effective enforcement of mandatory pet registration laws.

This would improve domestic cat ownership, reduce the number of unwanted cats, reduce the number of feral cats in parallel with TNR which will gradually over a period of say 20 years reduce the population of feral cats. It's a long-term project. There is no other way. But if they'd started this 20 years ago they would have made some progress by now.

Dr Amy Wilson, veterinarian and ecologist wants to limit free-roaming cats to protect wildlife

Professor Amy Wilson's research concluded that domestic cats are likely to blame for the spread of toxoplasma gondii to wildlife in urban areas where there are lots of cats. The researchers examined 45,079 cases of toxoplasmosis in wild animals. They found a correlation between the density of humans in urban areas and the likelihood of infection of the toxoplasmosis in wildlife. That is: the more dense the human population the more likely wild animals will be infected by zoonotic diseases such as toxoplasma gondii.

Professor Dr Amy Wilson veterinarian and ecologist. Photo: her bio page online.

Dr Wilson blames free-roaming domestic cats and feral cats for the 'most likely cause of the infections'.

She says that her research is "significant because by simply limiting free-roaming of cats, we can reduce the impact of Toxoplasma on wildlife.

ASSOCIATED PAGE: It Is Time to Stop Denigrating the Domestic Cat with Spurious Links between Toxoplasmosis and Human Mental Health

She states that one cat can excrete 500 oocysts in 14 days. But it should be noted this happens once in a cat's lifetime (my comment). 

"These infective oocysts are only passed for a very short time after initial exposure" (Cat Owner's Home Veterinary Handbook).

But these tough eggs can live for 5 years in soil where they can infect animals and humans. Humans and animals have to ingest the oocysts.

ASSOCIATED: Truth about Toxoplasmosis and Cats

A lot has been written about toxoplasmosis. A lot of it derogatory for the cat. It is nearly always asymptomatic in cats and humans. When the immune system is compromised it can cause ill-health.

Professor Wilson also says that maintaining healthy habitats and ecosystems helps to protect wildlife. She said:

"We know that when wetlands are destroyed or streams are restricted, we are more likely to experience runoff that carries more pathogens into the waters where wild animals drink or live. And when their habitats are healthy, wildlife thrives and tends to be more disease-resistant."

The study: "Human density is associated with the increased prevalence of a generalist zoonotic parasite in mammalian wildlife” by Amy G. Wilson, Scott Wilson, Niloofar Alavi and David R. Lapen, 20 October 2021, Proceedings of the Royal Society B: Biological Sciences. Link: https://doi.org/10.1098/rspb.2021.1724

Can I get toxoplasmosis from petting my cat?

No, you cannot get toxoplasmosis from petting your cat. You might get it from handling faeces from your cat in which there are toxoplasma gondii oocysts. It is rare though. A child might get them on her hands if she plays in a sandpit where a cat has pooped. The child then may put her hands into her mouth, as children do, and ingest the oocysts which would cause an infection in the child. But, I stress, you cannot get toxoplasmosis from petting your cat.

T. gondii oocyst. Image: MikeB.

It is interesting to note, by the way, that contact with your cat generally has no influence on the probability of people having antibodies to the parasite. In other words, contact with your cat does not expose you to toxoplasmosis resulting in antibodies being produced inside you as a defence against this disease. Kissing your cat might be more problematic. Read about it by clicking here.

That is why only 20% of people in the United Kingdom have antibodies to toxo. In contrast to that percentage, 80% of French and Germans do have antibodies to toxo because they eat more raw or undercooked meat.

That tells the clear tale that by far the majority of infections in humans of toxoplasmosis comes from eating raw meat. Let's do justice to the domestic cat and not frighten ourselves unnecessarily. If you want to protect yourself against toxoplasmosis then prepare your raw meats properly and don't eat like the French and Germans do!

I should also stress, by the way, that being infected with toxo from cat faeces can only happen during a two-week window in which the parasite is viable after the cat's first consumption of contaminated wildlife. It's a short period of time which further highlights the point that people can live with domestic cats safely and they should not be fearful of contracting toxoplasmosis from the cat. This also applies to pregnant women who simply have to take some precautions.

On that subject, if you are pregnant, you can reduce the risk in several ways:

• by wearing gloves when handling raw meat and by washing your hands afterwards;
• only eat thoroughly cooked meat or meat which has been smoked, cured or frozen for at least three days;
• by washing vegetables and fruit thoroughly before eating them; 
• and by wearing rubber gloves when gardening.