Australian Lefty on Politics, Governance, Science and Info Management

Kill cats, save humans (and the health budget)

Posted by Dave Bath on 2009-06-09

New Scientist presents even more evidence why we should develop a "cat calicivirus", wiping out all cats in Australia except those with owners prepared to cough up money for a vaccine – and preferably put money into a fund to compensate the nation for the 1500 Australians killed by cats every year (and that’s not including suicides by those with schizophrenia or a bipolar disorder).

New Scientist cites estimates of Toxoplasmosis-related road deaths worldwide between 400 thousand and a million each year (and then we should add in the costs of injuries and rehabilitation).  Toxoplasmosis would not spread if there were no cats.

As we cannot vaccinate every cat against the Toxoplasmosis parasite, the only alternative is to create a virus that kills all cats except those vaccinated against the cat-killing virus.

Those who were Rh-negative and had toxo were 2.5 times as likely to have an accident as uninfected drivers who were Rh-negative, or any Rh-positive drivers

Flegr says these results suggest that between 400,000 and a million of the world’s annual road deaths might be due to toxo infection. He suggests regularly testing Rh-negative pilots, air traffic controllers and truck drivers for the infection.

I don’t think dogs would attack, let alone be contributory causes to the death of anywhere near that many people each year.

This relates to accumulating evidence that the archetypal "mad old cat lady" liked cats and then became mad.

More quantitatively, early exposure of children to cats dramatically increases the risk of the child being diagnosed with schizophrenia.

So, to reduce the costs associated with road trauma, the Transport Accident Commission and similar agencies in other states should engage in a massive cat eradication program, lowering (if Flegr’s estimates are right) the average death tolls in Australian states by a couple of hundred.

It’s obviously more ethical (and certainly cheaper during regulatory approvals) to design a bug and vaccine specific to cats rather than immunize all humans.

…and Australia is the perfect place to release it, because there are no native cats, and the beneficial effects on native wildlife would be huge.

But killing one cat isn’t enough to stop what must be a significant portion of government spending in countries with many cat lovers… you have to ensure that people don’t come into contact with cats that have been infected with T. gondii – and that’s nearly all of them.  (Add up the costs of road accidents, the cost of treating 50% of schizophrenics and the significant costs associated with social services and lost productivity for schizophrenia and bipolar disorders… if it comes much under 1% of government spending I’d be surprised.)

Maybe when motor vehicle insurers demand an extra charge for cat lovers, especially Rh-negative ones, in the same way that life insurance costs more for smokers, then something might change and many preventable deaths, on roads, and through suicide, wouldn’t happen any more, and our hard-pressed native wildlife will be happier.

And I wouldn’t mind if, because of a highly desirable eradication of felids in Australia, the only cats I like had to change their name back to "The Seagulls"

See Also/Notes:

  • "Increased incidence of traffic accidents in Toxoplasma-infected military drivers and protective effect RhD molecule revealed by a large-scale prospective cohort study" (2009-05-26) BMC Infectious Diseases 2009, 9:72doi:10.1186/1471-2334-9-72 also suggests RhD polymorphism may arise because of the need to protect ourselves from cats (Rh+) versus the benefits of Rh- that must explain the continued existence in the population despite the plague of cats.

    Our results show that RhD-negative subjects with high titers of anti-Toxoplasma antibodies had a probability of a traffic accident of about 16.7%, i.e. a more than six times higher rate than Toxoplasma-free or RhD-positive subjects.

    …and yes, I note the difference in these figures from that in the New Scientist article.

  • "Parasite may increase your odds of an auto accident" (2009-06-09) New Scientist  – up to 2.5 times more likely if you are Rh-negative
  • "A Unique Dual Activity Amino Acid Hydroxylase in Toxoplasma gondii" PLoS One
  • "Toxoplasmosis parasite may trigger schizophrenia and bipolar disorders" (2009-03-11) Science Daily
  • From the US CDC (Centre for Disease Control):
    • "Toxoplasmosis/Pregnant women"

      Most infected infants do not have symptoms at birth but can develop serious symptoms later in life, such as blindness or mental disability. Occasionally infected newborns have serious eye or brain damage at birth.


    • "Toxoplasma gondii and schizophrenia" (2003-11)

      Since 1953, a total of 19 studies of T. gondii antibodies in persons with schizophrenia and other severe psychiatric disorders and in controls have been reported; 18 reported a higher percentage of antibodies in the affected persons; in 11 studies the difference was statistically significant. Two other studies found that exposure to cats in childhood was a risk factor for the development of schizophrenia.

  • "Maternal Exposure to Toxoplasmosis and Risk of Schizophrenia in Adult Offspring" Am J Psychiatry 162:767-773, April 2005

    CONCLUSIONS: These findings suggest that maternal exposure to toxoplasmosis may be a risk factor for schizophrenia. The findings may be explained by reactivated infection or an effect of the antibody on the developing fetus. Given that toxoplasmosis is a preventable infection, the findings, if replicated, may have implications for reducing the incidence of schizophrenia.


  • "Research supports toxoplasmosis link to schizophrenia" (2009-03-11) University of Leeds Media Release

    "In addition, the ability of the parasite to make dopamine implies a potential link with other neurological conditions such as Parkinson’s Disease, Tourette’s syndrome and attention deficit disorders, says Dr McConkey. "We’d like to extend our research to look at this possibility more closely."

  • Cat’s are parasites themselves – see 3quarksdaily referencing Scientific American
  • My daughter, much to my horror, has a cat and my grandson is exposed to it.  I’ve been banned from using such phrases as "Evil Kitty" in my grandson’s presence, so I’ve taken to referring to it as "Her Maleficence".  Unfortunately, my hatred of cats doesn’t extend to cruelty, so if it’s bowl of water is dry, I refill it while saying "I am NOT your friend". It doesn’t stop me cheering the local magpies when they taunt the spawn of Satan.


10 Responses to “Kill cats, save humans (and the health budget)”

  1. memeweaver said

    I’m afraid I’m a committed Satanist (read: cat lover) and prefer my children to befriend the devil as well. The chances of contracting toxoplasmosis from a cat that spends at least half its life indoors are pretty minute, as, from what I understand, toxoplasmosis has a very limited life in an infected cat (I think it’s only a couple of weeks), and once infected, they can never be infected with it again. I’m happy to be corrected on this score, but will sinfully refuse to acknowledge the fact I could be wrong.

    To my bedevilled mind, to say that there’s a risk of developing schizophrenia from cats is equivalent to the risk of getting flu from a pig. Sure, the risk is there, but how significant is it? And I’m that much of a brain-washed bigot and a stubborn devil-worshipper that I’m not going to go ahead and follow those useful links you’ve got there to informative articles on the subject. In any case, I think the risk of developing schizophrenia is more than counteracted by the fact that pets (spawns of Satan included) are proven to reduce depression in the lonely (couldn’t give you a link to save my soul, which has already been sold to the devil anyway).

    So, anyway, instead of coming up with a virus to kill off cats, why not come up with a virus (or at least a criminal penalty) for those who smoke or drink whilst pregnant, and then continue to smoke following the birth of the baby, thereby exposing their child to the risk of cot-death, lung cancer and a lifetime of unhealthy and expensive habits? Just a thought. The devil made me do it.

  2. Dave Bath said

    Toxoplasmosis is one of those things that tend to have a lifelong effect (a bit like chicken pox… decades later shingles appears). As for infected cats, it is worth remembering that there is an evolutionary advantage for the cat when shedding the parasite for life – any potential prey in your area is more likely to do stupid things and get eaten later. (Mice, for example, once infected and the acute infection is long past, no longer worry about the smell of cats, stay out later at night, further from their mouseholes, etc. I’m imagining an old Warner Bros or Tom’n’Jerry cartoon, the depressed mouse carrying an “EAT ME” sign and forcing itself into the cat’s mouth.)

    While mice are the target of F. domestica and F. silvestri, we primates were regular items on the menu of felids only a few millenia ago, which probably explains why our brains, like mice are affected by toxo, whereas cats aren’t. Toxo wants cats to be healthy, and the prey of cats to be stupid.

    Some of the latest theories are looking at the possibility that it is not the parasite directly causing neurological changes, but the antibodies made against those parasites.

    The significance? Just for motor accidents, from half to one million people a year dead and attributable to toxo. Compare that to annual average toll over the last decade from all wars, and then compare the number of letters to the editor, street protests, yada yada yada.

    The risk of schizophrenia is non-trivial. A French retrospective study (gotta find that link again… read it about 5 years ago) found that the risk of schizophrenia was approx doubled (taking into account family history, etc) not merely by early infection (it’s hard to tell WHEN a person aged 50 was infected at 3 or 30), but when a pre-schooler was exposed to cats. The more cats, the younger the child, the greater the associated risk. With 1% of the population suffering from schizophrenia alone (not the other disorders now becoming linked to toxo) it’s a significant social problem – compare this to incidence of all cancers, which is approximately 0.5%. If the risk is increased by between 50 and 100 percent by early cat exposure (from memory, I think it was a 75% increase), then that is a lot of people. My guess is that toxo infection can push those who have a predisposition to schizophrenia over the edge.

    To be blunt, it appears from meta-analyses that T.gondii is THE MAJOR risk factor for schizophrenia. (from doi:10.1093/schbul/sbl050)

    Although the OR of 2.73 is modest, it exceeds that for genetic or other environmental factors identified to date and suggests that Toxoplasma is in some way associated with a large number of cases of schizophrenia.

    When that study was published a couple of years ago, the evidence was purely epidemiological. It’s only this year that the aetiological “smoking gun” was found, involving dopamine pathways.

    The good news from this is that parents with schizophreniform illnesses, or with sufferers in the family, should get some relief from the fears and guilt about passing on “bad genes”.

    And I’m sorry, but “mainly indoor” doesn’t cut it – just like “mainly wears a condom” doesn’t. All a cat has to do is chew a mouse that had previously been infected.

    The other thing to note is that for some unknown reason, toxo-exposed (no active infection) women are rated as more desirable by males. This presents an advantage to cat-loving women, because if more attractive (whether through appearance or risk-taking behaviour), they are more likely to have more kids. Think of why Huntington’s is so big in Taswegia, for instance. Those who will go on to exhibit HC by 40 years are more promiscuous in early adulthood.

    And yes, I totally agree with you about the undesirability of smoking, etc with pregnancy. There has already been a case in the US a few years back where a child sued the mother for just this reason. Unfortunately, many teratogenic problems arise BEFORE pregnancy is discovered. (As for lung cancer, it doesn’t matter as much if your child spends a lot of time in a dairy shed… something in dried cow dung seems protective for the most common lung ca. Perhaps those who become nuns and get breast cancer – it was the first occupationally linked cancer – should sue their mothers for baptizing them R.catholics and encouraging them to a nunnery without first explaining the risks. Lots of complications in epidemiology!)

    I’ll admit, some depressed people DO get symptomatic relief from being cat slaves. But then, heroin gives symptomatic relief to opiate addiction.

    I’ll also admit I’m very ready to use any ammunition against cats I can get. Ditto (in Oz, at least) rabbits (love the New Scientist Easter Bunny), cane toads, foxes….. If I was the one assembling the evidence, then I wouldn’t blame moggymaniacs from distrusting my assertions….

    …but the lead researcher on cats and schizophrenia for the last 30 years (E. Fuller Torrey) actually likes cats, although jokes that his wife reckons he’ll be assassinated by moggy lovers. In that interview, a few key hints are discussed, including

    Torrey, who had recently (in the 1970s) completed a book manuscript arguing that in the late nineteenth century schizophrenia and bipolar disorder went from being rare diseases to relatively common ones, became convinced that cats were central to that story. “The cat craze began with the cat shows in the late nineteenth century,” he explains. “And when I went back and looked at what we know about cats as pets, it corresponded almost perfectly to what we know about the rise of psychosis.”

    And, it’s worth having a look at this post on cat-transmitted diseases by the resident guest cat-hater on a cat-loving blog. Not as legs up laughing as book review at a ("Discuss Laboratory Exercises in Anatomy and Physiology with Cat Dissections (7th Edition) on the ‘Cat Book Reviews’ forum of I-Love-Cats . I-Love-cats is the ultimate Cat Lover website where you can interact and talk about Laboratory Exercises in Anatomy and Physiology with Cat Dissections (7th Edition) with Cat lovers around the world.").

  3. Dave Bath said

    Oh, and from the same interview with Torrey:

    Dog ownership, by contrast, was marginally more common among nonschizophrenics

  4. memeweaver said

    Yeah but, no but, yeah but…

    Oh dear. That would explain the fat rats I have seen consumed lately.

    If you could only meet Rufus and Herbie, you would no doubt fall under their diabolical power of enchantment. Err. I mean, you would understand why I have. Or probably not.

    Oh well. I’m not about to engage in some spontaneous dissection of my beloved felines any time soon. So I guess it’s back to Plan B post haste: Hear no evil. See no evil. Handle no evil. (Evil being NOT my cats, of course, even if it might be other people’s.)

    So how much did you say that vaccine was again?

  5. Dave Bath said

    The vaccines to my hypothetical virus don’t exist. (SoundFX: Evil cackling as I flick through a catalog of ultracentrifuges and micropipettes. Cursing as I remember I’ve only engineered a resistant-to-any-antibiotic-you-can-throw-at-it E.coli, have only chopped up plasmids, but haven’t any viral experience). Human vaccines against toxo are problematical, as it /might/ be the antibodies themselves that are involved in the problem.

    Even with cats, I’d never go for “spontaneous dissection”. Mammals (and a few birds) should only be sacrificed for good reason, and with compassion. Sacrificing higher animals is hard, particularly when you think the species is adorable and intelligent, like a lab rat. (Mice are detestable tho).

    And, I reckon that we can all agree that a rat with a teddy bear (awake or asleep under a blanket, or asleep without a blanket) is unutterably cute.

    The Cats and Dogs film got it spot on.

    Apart from Cats that run around Kardinia Park and kick a fair drop punt, the only cats I’ve got on with were a couple that had been raised by a sheepdog and THOUGHT they were dogs. If your Rufus and Herbie are similarly unaware of their own cattishness, then maybe I’d find their personalities charming rather than merely infectious. Given that they are ratters, not merely mousers, were they raised by terriers?

  6. memeweaver said

    Oh, bother. A non-existent virus and two non-existent vaccines to boot. We are doomed. Your evil cackling is quite disturbing, if it weren’t for the fact that my beloved (toxic) felines are now immune to your dastardly machinations.

    Agreed wholeheartedly on dissection. Not agreed on mice. My karma was forever compromised when I laid a big purple bait after suffering the repeated ransacking of my pantry and then had to watch a poor tiny mouse quiver and die in the middle of my lounge room floor, its nervous system completely kaput. Also, my experience of dissection was forever blighted by watching with horror as a group of completely compassionless boys in my science class, upon discovering that the mouse they were dissecting had been pregnant, proceeded to throw the unborn foetuses around the classroom. Sorry for that image. No doubt they’ll be reborn as lab mice.

    Admittedly, rats with teddy bears are charming. As are rats cuddling up to cats. As is a certain ratcat I know. As is Rufus, who is no ratter or mouser. But who evinces an uncanny unawareness of his cattishness, as he is predisposed to chase balls of squashed up paper and bring them back in his mouth. Beyond this, his utilitarian value ends. Except maybe as a hot water bottle. Or an alarm clock, if you need to get up at some ungodly hour. Charming though.

  7. Jacques Chester said

    You’d want to wipe out rabbits first; feral cats probably prey on them as well as native species. Take the cats out of the picture and you’d see a population explosion.

  8. Dave Bath said

    JC@7: We already have calicivirus which controls things, and can always tweak another bug in a decade or so when the long-eared buggers become immune. It’s not like a few years ago when you couldn’t help but hit a bunny if you were to fire a gun randomly out of a train almost anywhere between Melbourne and Warrnambool. Besides, bunnies don’t harbour something like toxo and aren’t infesting cities full of people.

    In this respect, non-urban feral cats are less of a problem than the non-ferals. At least with the non-urban feral cats no-one will mind if you take to them with a 22.

  9. […] to cane toads which at least don’t impose a significant cost to human health (see "Kill cats – save humans and the health budget" – […]

  10. Thanks for your reviews! I had filled in all but my credit card quantity when I imagined I must read some reviews…whew!
    Glad I did! Thanks for saving me the $150!
    Consider I will just go and buy a Food Processor and slicer!

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