NASA needs to clean up its robotic spacecraft better or risk colonising Mars with terrestrial microbes, an expert panel has warned.
But it says the reforms will probably take at least a decade to put in place, raising the chance that earthly life could still stow away on spacecraft scheduled to visit the Red Planet before then - if it has not done so already.
Already, indeed. By my reading of the Wikipedia article on Exploration of Mars, at least 10 Earth-launched devices have landed or crashed on Mars: Mars 3 (1971), Mars 6 (1973), Vikings 1 and 2 (1975), Pathfinder (1996), Polar Lander (1999), Deep Space 2 Mini Probes (1999), Beagle 2 (2003), and the Spirit and Opportunity Rovers (2003).
Engber considers the prevalence of "cat hoarders" (who are usually women) without considering the most obvious -- at least to my intuition -- cause: toxoplasmosis infection.
Toxoplasmosis is a disease caused by a protozoa parasite whose lifecycle can cross cats and other animals, but only sexually reproduces inside cats. There's strong evidence that toxo-infected rats and mice have their behavior affected by the parasite in ways that make them more likely to be captured by cats: their reactions are slower, they're less fearful of new situations, and they even seem to be drawn to the smell of cat urine (whereas non-infected cat prey will wisely avoid all cat smells).
There's also evidence toxo-infection can have analogous effects on infected humans -- subtly altering their personality and making them more prone to, among other things, dangerous accidents. This writeup (which I believe is an uncreditted reprint of a New Scientist article) is a good summary. Let's compare Engber's observations about "cat ladies" with the observed effects of toxoplasmosis on mammals:
Engber on 'cat ladies'
New Scientist on toxoplasmosis victims
"In most cases, animal waste dirtied the home; the hoarder's bed was sometimes found to be covered with feces or urine."
"[Toxoplasmosis] releases eggs that are spread in cat faeces, and if these end up in moist soil they can remain infective for 18 months."
"But the real clincher came when the researchers offered the rats a choice of bedding - their own, or bedding laced with water, cat urine or rabbit urine. Cat urine is usually a big turn-off for rats, but the toxo-rats actually preferred it."
"Not all animal hoarders are cat ladies, but most are."
"[A 1981 New York City study] found that two-thirds of the obsessive collectors were women and that 70 percent were single."
"Infected men tended to be more independent and inclined to break rules, although infected women tended to go the other way. Could it be that males are being made more reckless, like the rats, while for some reason the mind-control chemical has the opposite effect in females?"
"Researchers say that most obsessive animal collectors deny that they have a problem. Many claim to have a special ability to communicate with their animals and insist that all their pets are well-loved and in good health. (In fact, the animals are often dying around them; animal control officers found more than 200 dead cats in two homes owned by the Knueven family.) Some psychiatrists say these beliefs, along with a paranoid fear of government intervention, may constitute a delusional disorder."
"[I]n rare cases [toxoplasmosis] can lead to serious eye damage."
"Another controversial idea is that latent infection might trigger some forms of schizophrenia. Fuller Torrey at the Stanley Medical Research Institute in Maryland and his team has found that schizophrenics are more likely to be cat owners, and to have latent toxoplasmosis. What's more, drugs used to relieve schizophrenia symptoms happen to harm the parasite, at least in the test-tube. Torrey believes this may be why the drugs work."
The cats aren't just a symptom of 'cat hoarding'... they're also an original cause.