Transgenic Cats and their afterglow

In this post: Cat Brain Parasite update!
and
New experiments into Feline Immunodeficiency Virus produce publicity friendly glowing kittens –
a genetically engineered cat

I CAN HAZ RETRO-VIRALZ?


But first: Felinology round-up.

Following on from speculation reported last time as to why cats are loved by humans, new research published in Nature Neuroscience suggests an emotional response to animals may have become ‘hard-wired’ in the human right amygdala, a part of the brain associated with emotion. This was picked up by ABC News in America, focussing on the cat angle. According to ABC’s Lee Dye, Florian Mormann, the new paper’s lead author said:

Given the amygdala’s prominent role in fear conditioning, we were indeed expecting stronger responses to hazardous animals such as spiders or snakes, but it turned out that all kinds of animals, dangerous and cute, elicit responses in the amygdala

This doesn’t explain why cats in particular evoke such love in humans, however, nor why science writers have used the research to comment on cats in particular. So ABC: a hiss and mild indifference at thee – it ain’t all about cats, it’s about humans and evolution.

Blogger Dan Tandy writes Dogs have masters, cats have staff:

A cat’s affection is almost medicinal in its effects. It’s believed cats can sense moods, fully aware if you’re upset or unwell. They’re very sensitive creatures and like to look after their staff. A cat will rub its head on you to mark its scent, secreted from an odourless sweat gland under its ear, essentially marking you as their property, along with everything else they see of course. This I think is also a sign of affection.

Research published early this year on human/cat dyadic behaviour was also widely reported, with reports focussing on the finding that cats seem to interact more with female than male companions. The research, in its own words, finds other significant factors however: the more ‘extrovert’ and ‘conscientious’ the human, the more complex the pattern of interactions, for example.

In our human–animal research, the effect of personality in dyadic relationships is a central focus…The cat, by its mere presence, may have an edge in this negotiation, at least with contact-seeking owners. The owners’ main asset in motivating the cat to be trustful, devoted and open to contact may be in proving to be a trustworthy and dependable social companion

The upshot of this is that the relationship is social and more than just a functional ‘you give me food, I catch mice’ trade-off:

human–cat companionship is not overtly operational in the sense that the partners go places and do things together. In many modern households, cats that get their food from their owners do not reciprocate by catching mice. But human–cat dyads are surely functional in a social sense. The cats in our dyads were regarded by their owners as valuable social companions and social supporters (Kotrschal et al. unpublished data). The social significance of this companionship is less clear on the cats’ side, although well-socialized cats do actively seek human contact (Leyhausen, 1988 and Turner, 2000). It is unlikely that cats do this just for the sake of obtaining food. Cats are clearly capable of attaching socially to “their” humans. In general, attachment in higher vertebrates is basically contingent upon, but not caused, by the provision of food (Bowlby, 1972 and Curley and Keverne, 2005).

Ever heard that high-pitched noise come from a cat, a cry and purr combined when the cat wants something really badly?Cats may have learned this to control humans, mimicking the noise made by a hungry infant.

All of this lends support to the idea that the solitary cat is a myth, and cats are indeed social animals.

Cat intelligence, meanwhile, seems to be the standard which humans attempting to create Artificial Intelligence aim for.

OK, back to the glowing cats. Yeah yeah, cats fluoresce now. Unsurprisingly, news of genetically engineered cats that glow under UV light, a cliché of genetically engineered animals, has been widely reported both in the mainstream and the blogosphere. A key issue is FIV, the feline equivalent of HIV, which this particular colony of cats are testing in the name of human and -as the reprots empahsise – cat health. Big up to the sans science blog for a quick and interesting post on the story, with good links and a sharp hiss at the clinic’s press release, described as ‘nauseating‘.
Maia Szalavitz, resident felinology wonk at TIME has written
an informative piece focusing on FIV, the technique and the prognosis for future research. Maia points out these are not the first UV sensitive cats ever produced, and passes on the reassurances of the human experimenter Dr. Eric Poeschla:

Three kittens, two males and one female, were born. “The kittens are completely normal — frisky, happy, healthy and interactive,” says Poeschla, adding that they seem completely unfazed by their ability to glow.

Meee-ouch! meanwhile reports that

after 22 attempts, the first cat to successfully have its DNA altered, bore a litter of 5 kittens, 3 survived and 2 went on to have litters of their own, carrying on the modified DNA. All cats were able to fight the FIV virus better than that of a normal domestic cat.

No word as to what happened to the 22 ‘unsuccessful’ cats or whether the humans infected them with FIV too. It’s interesting how the reports focussed on the florescence of the cats, rather than their FIV infection. Is it possible to use cats found and diagnosed with FIV, instead of infecting healthy cats with the virus? Too expensive to control the variables perhaps?

The only fly in the ointment as it were comes from the Dolly the Sheep people, who are quoted as suggesting, bizarrely, that feline test subjects may be less suitable than ‘more common’ lab animals like rats or mice. Siouxie has no comment as to these creatures lot, but suggests no animals are no substitute for human experience in human disease.
As for FIV+ catkind, if some can be treated they should – if they are made to glow under UV light in the process so be it, but this should not be forced on any cat.

Toxoplasmosis gondii updateLast time it was promised this blog would report on the risks associated with T. gondii. The brain-altering parasite with cats as its primary host may have first evolved in either Africa (like the tabby cat) or South America.

The issue of prevention raises a dilemma for those cats interested in a raw diet, since raw meat is one of the main risks of toxoplasmosis.

Siouxie’s diet is now at least 87 per cent meat, consisting of around 65% canned meat, 35% dry biscuits (which are 96 percent meat and mere 4% grain). This is supplemented with bits of cooked fresh meat, crushed eggshell (boiled first) and membrane, and the occasional cream or cheese crumb. No raw meat as yet, as far as anyone is aware.

On this issue, certainly for humans raw untrusted untested meat is the main risk here, but cats are evolved to eat raw meat, and it is widely assumed amongst raw cat food advocates that cats fed on a raw diet are, in the long run, healthier, happier and longer living cats. Moreover, “odd as it may seem, a healthy cat that tests positive is probably safer than a cat that tests negative”.

A theme which constantly emerges is that cats often get the blame for Toxoplasmosis, being the definite host, while people are far more likely to catch it from undercooked meat. An infected cat can only pass it on for two weeks, and is unlikely to do so anyway since the cat will clean the oocytes from it’s fur. There is an increased severity risk for pregnant woman – and their embryonic human child – from T. gondii for those two weeks, and this risk is well advised to be guarded against. The only real risk would appear to be from humans cleaning the cat’s toilet – but for a roaming, or garden cat, a dedicated patch in the garden would be the obvious way to avoid cleaning the litter tray, any subsequent gardening requiring a quarantine and heavy mulch time.

Despite simple ways to avoid infection, the symbiote is being used as a reason to advise people not to allow cats to roam freely, or to eat raw meat. Furthermore, it seems the effects on humans have been overstated.

Siouxie’s advice: don’t panic!

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Fellow Travellers

Symbiosis and Sustainability – ‘the problem with pets’
As Suzie ventures into the unknown, the possibility that he will pick up unwanted visitors along his travels haunts.  Him catching fleas preoccupies Angela, an occasional scratching cat provoking the dread of an infestation. Of course there are remedies: collars, powders and so on, the paraphernalia of cat consumerism, not only expensive but risky, as the environmental lobby points out.

So many products on the market are comprised of toxic, harmful chemicals, terrible for the pet and dangerous if you have young children. They can even create resistant generations of fleas that are no longer killed by the treatments and weaken your animal to become vulnerable to further infestations. What are we to do?

A sustainable pets movement is possible, according to Southern Fried Science. ‘The Problem with Pets’ is that

pets have a real and lasting impact on both social and natural ecosystems,their position in society is problematic,and when talking about living sustainably,the choices we make with regards to our pets matter

The first step in becoming a sustainable pet owner is asking yourself,“do I really need a pet?”Remember,the lowest environmental impact you can have regarding your pets is none at all. Take the money you’ll save from not owning a pet and donate to local organizations that help reduce feral animal populations. Beyond that,there are three guidelines that will help you define what is and is not a sustainable pet…

Symbiosis
The word ‘symbiotic‘ (meaning together-alive) describes a close, mutual relationship between life forms, “the living together of unlike organisms”.

The cat/human bond, one of many symbioses, multifaceted with benefits and compromises, goes back thousands of years. Anecdotal evidence of humans love for cats is widespread. But there seems to be a need to explain, simply or definitively, why this is so. Maia Szalavitz, writing in TIME Healthland, speculates a third life form may be responsible, a clever yet tiny ‘parasitic infection’, Toxoplasma gondii.

A parasitic relationship is one type of symbiosis, and the term ‘parasites’ covers both life forms that kill their hosts and those that need their hosts alive. Toxoplasma gondii, or T.gondii for short, infects mammals but can only sexually reproduce in cats, so needs to infect cats to continue its life cycle. Thus the cat is known as the ‘definitive host’.

t.gondi life cycle
the life cycle of T.gondii

In increasing its chances of getting into cats, T.gondiihas achieved something rare for such a simple organism – it can affect the minds of infected rodents.

Rats and mice, cleverly enough, normally flee from the mere hint of cat odour knowing it means trouble. But when infected with T.gondiithey become attracted to cats natural smells.

t.gondi life cycle
another view of the cycle

T.gondii seems to raise dopamine in just the right parts of the brain to fool the rodent the cat’s a potential mate. The cat can then easily catch and eat the rodent and the parasite easily crosses over into the cat. The cat gets a free rodent and T.gondii gets a free ride to a new spawning generation.

In the TIME piece, Szalavitz asks, referencing one study that suggests

infected women were warmer and friendlier than non-infected women…does T. gondii also cause cat ladies to collect furry felines? No research appears to have been done directly on this subject, though one study did find a connection between the bug and obsessive-compulsive disorder, of which animal hoarding is one form

This is tenuous in the extreme; we can’t say T. gondii affects humans in the same way. Why would it? There’s no evolutionary advantage to it, since cats do not routinely ingest humans. Suzie would have thought it far more interesting to look at what the risks to the cat are, and how to minimise the general risks for cats and humans alike. This blog will report on this soon, but cats are very unlikely to catch T.gondii from humans, as the life-cycle diagrams above indicate.

But let us first look deeper at the clever little critter, investigated ‘scientifically’ for years, which with something like this means animal experiments.

t.gondii
Foreground -T.gondii at work. Background - T.gondii cyst in the brain

A 1998 paper observes T.gondii build tiny cysts ‘in the neural and muscular tissues, including the brain, eyes, and skeletal and cardiac muscles”. Reassuringly, if indolently, the researchers reckon “tissue cysts probably do not cause any harm and can persist for the life of the host without causing…inflammatory response”.

News of the mind-control effect the organism has on rodents was published as long ago as 2000 by the Royal Society:

Fatal attraction in rats infected with Toxoplasma gondii (Abstract).
T. gondii’s manipulation appears to alter the rat’s perception of cat risk, in some cases turning their innate aversion into an imprudent attraction…this ubiquitous parasite subtly alters the brain of its intermediate host to enhance predation rate whilst leaving other behavioural categories and general health intact. This is in contrast to the gross impediments frequently characteristic of many other host–parasite systems.

Note the emphasis on the health of the intermediate host, and not the cats. In 2006 researchers in America also found mice and rats with T. gondii lost their fear of cats, and that “such loss of fear is remarkably specific, because infection did not diminish learned fear, anxiety-like behavior, olfaction, or nonaversive learning”. This 2011 research, which has caught Szalavitz’s eye, seems further confirmation of the effect, finding:

rats infected with the brain parasite approach the cat odors they typically avoid…this change in host behavior is thought to be a remarkable example of a parasite manipulating a mammalian host for its own benefit.

Suzie Bubbs will not say. He’s yet to catch a rat or mouse, and when he does he will let the humans know, sure they will be entertained by the spectacle. For now, parasites can take their own chances.