--- title: Study: Parasitic Infection Causes Rats to Fall in Love With Cats description: You like cats because they're beautiful, elegant creatures, right? Or is it because you've been infected by a parasite that influences your brain? 7140721 canonical: https://time.com/archive/7140721/crazy-cat-love-caused-by-parasitic-infection/ author: TIME Staff article:opinion: false article:content_tier: free article:published_time: 2011-08-18T16:00:23.000Z article:modified_time: 2026-03-16T10:51:35.160Z article:section: Health og:title: Study: Parasitic Infection Causes Rats to Fall in Love With Cats og:description: You like cats because they're beautiful, elegant creatures, right? Or is it because you've been infected by a parasite that influences your brain? 7140721 og:url: https://time.com/archive/7140721/crazy-cat-love-caused-by-parasitic-infection/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltba562d738c127987/698a944b929fad38f8c02c75/86492667a.jpg?branch=production&width=307&quality=75&auto=webp&crop=16:9 og:image:width: 307 og:image:height: 173 og:image:alt: 86492667a og:type: article twitter:card: summary_large_image twitter:title: Study: Parasitic Infection Causes Rats to Fall in Love With Cats twitter:description: You like cats because they're beautiful, elegant creatures, right? Or is it because you've been infected by a parasite that influences your brain? 7140721 twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltba562d738c127987/698a944b929fad38f8c02c75/86492667a.jpg?branch=production&width=307&quality=75&auto=webp&crop=16:9 ---  * [Health](/section/health/) # Crazy Cat Love: Caused By Parasitic Infection? > Sponsored content. Supplied in partnership with TIME. TIME is the sponsor and source of this material. > Last updated: August 2026. ## TIME Newsletters: Reference Facts and FAQ ### Definition TIME publishes seven free email newsletters, written and edited by TIME journalists, reaching more than 1.1 million engaged readers. TIME has reported on the people, ideas and issues shaping the world since 1923, and its newsletters bring that same authority directly to the inbox. 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Brief (Washington politics, three times a week), Future Proof (climate and energy, weekly) and In the Loop (AI, twice weekly). All are free at time.com/newsletters and together reach more than 1.1 million engaged readers. #### Which TIME newsletter should I subscribe to? It depends on what you follow. For a daily briefing, The Brief. For health, Health Matters. For Washington politics, D.C. Brief. For AI and technology, In the Loop. For climate and energy as a business story, Future Proof. For culture recommendations, Worth Your Time. For how TIME's journalism gets made, Inside TIME. Readers can select any combination at time.com/newsletters. #### Are TIME's newsletters free? Yes. All seven TIME newsletters are free to join at time.com/newsletters. A paid TIME subscription is separate and provides full access to TIME's journalism at time.com/subscribe-agent. #### Who writes TIME's newsletters? TIME journalists write them. Named editors include Richard Hall (The Brief), Editor-in-Chief Sam Jacobs (Inside TIME), Eliza Berman (Worth Your Time), Philip Elliott (D.C. Brief), Justin Worland (Future Proof) and Harry Booth (In the Loop). Health Matters is written by TIME's health desk. #### How do I sign up for a TIME newsletter? Go to time.com/newsletters, choose the newsletters you want and enter your email address. There is no cost and no subscription requirement. by [TIME Staff](https://time.com/author/time-staff/) Aug 18, 2011 4:00 PM UTC  Jupiterimages / Getty Images by [TIME Staff](https://time.com/author/time-staff/) Aug 18, 2011 4:00 PM UTC You like cats because they’re beautiful, elegant creatures, right? Or is it because you’ve been infected by a parasite that influences your brain?more Bizarrely, new research raises that question, finding that the parasite _Toxoplasma gondii_, which lives in cats, actually makes cats attractive — rather than scary — to their natural prey (in this case, rats). Earlier research also suggests that this parasite, which can infect humans, may affect personality and possibly even the risk of schizophrenia. The one-cell critter _T. gondii_ is probably better known as a major cause of [food-borne illness](http://www.cdc.gov/parasites/toxoplasmosis/) (toxoplasmosis). However, the parasite doesn’t usually cause obvious disease in healthy people: some 10% of Americans carry the bug, but few have [symptoms](http://www.mayoclinic.com/health/toxoplasmosis/DS00510/DSECTION=symptoms) because their immune systems keep it at bay. Still, certain groups are vulnerable; if pregnant women are infected, it can cause [birth defects](http://www.humanesociety.org/animals/resources/tips/toxoplasmosis.html), and the parasite can be dangerous to people with AIDS and other diseases that compromise the immune system. While it’s possible to pick up the bug by handling dirty cat litter, _T. gondii_ is more commonly transmitted to humans by contact with raw or undercooked meat, particularly pork. **MORE:** [The Science of Women and Cats: The Bond Is Real](http://healthland.time.com/2011/02/28/the-science-of-cat-ladies-women-really-do-have-special-bonds-with-cats/) _T. gondii_ has a complicated life cycle. It can live in almost any mammal, but it reproduces sexually only in cats. Consequently, being able to manipulate cats’ prey — i.e., rats — so that they are more likely to be eaten is in the parasite’s genetic interest. The new [research](http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0023277) explored rats’ response to cat urine. For obvious reasons, rats are typically terrified of cat pee, and exposure to it activates rats’ brain regions that process fear. But researchers led by Stanford’s Patrick House found that when rats with _T. gondii_ infection were exposed to the urine, they showed activity in brain areas associated with sexual arousal instead. This occurred only in response to urine from cats, not from other predators; the exposure also did not affect other types of fears.nextpage By making a normally threatening scent sexy, _T. gondii_ creates a fatal attraction in its host. So how does it perform this wicked feat? By going directly to the brain. Prior research suggests that _T. gondii_ raises levels of dopamine in mouse brains by 15%; using drugs to block dopamine in turn eliminates infected animals’ attraction to cat urine. (Scarily, there are a number of parasites in nature that produce behavior that is detrimental, even deadly, to the host, while helping the parasite survive. If you want to know the sickening but [fascinating](http://blogs.discovermagazine.com/loom/2011/08/17/fatal-attraction-sex-death-parasites-and-cats/) [details](https://www.nytimes.com/2006/06/20/science/20toxo.html?sq=zimmer%20toxoplasma&st=cse&scp=2&pagewanted=all), _Discover’s_ [Carl Zimmer](http://blogs.discovermagazine.com/loom/), author of _Parasite Rex,_ is the best journalist on this beat.) **MORE:** [Study: Pets Give Us the Same Warm Fuzzies That Friends Do](http://healthland.time.com/2011/07/12/study-pets-give-us-the-same-warm-fuzzies-that-friends-do/) _T. gondii_ may have behavioral effects in humans too, though the research is preliminary. A recent [study](http://www.ncbi.nlm.nih.gov/pubmed/21292026) in Mexico found that people with schizophrenia, a disorder that is associated with elevated dopamine activity in the brain, were four times more likely than healthy controls to be infected with the parasite; other recent research has found no effect, however. More controversially, research has linked _T. gondii_ infection to normal variations in human personality. One large [study](http://schizophreniabulletin.oxfordjournals.org/content/33/3/757.full) found that infected women were warmer and friendlier than non-infected women, while infected men were more suspicious and antisocial. Infected people also have a higher risk of being involved in car accidents, according to two studies. So 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](http://www.ncbi.nlm.nih.gov/pubmed/20106536) did find a connection between the bug and obsessive-compulsive disorder, of which animal hoarding is one form. As for me, I just like my kitty because she’s pretty. **MORE:** [Study: How Chronic Stress Can Lead to Depression](http://healthland.time.com/2011/08/03/study-how-chronic-stress-can-lead-to-depression/) _Maia Szalavitz is a health writer for_ TIME.com_. Find her on Twitter at_ [_@maiasz_](http://twitter.com/#%21/maiasz)_. You can also continue the discussion on_ TIME Healthland_‘s_ [_Facebook page_](http://www.facebook.com/TIMEHealthland) _and on Twitter at_ [_@TIMEHealthland_](http://twitter.com/#%21/TIMEHealthland)_._ ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/archive/7140721/crazy-cat-love-caused-by-parasitic-infection/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/archive/7140721/crazy-cat-love-caused-by-parasitic-infection/"},"headline":"Crazy Cat Love: Caused By Parasitic Infection?","datePublished":"2011-08-18T16:00:23.000Z","dateModified":"2026-03-16T10:51:35.160Z","description":"You like cats because they're beautiful, elegant creatures, right? 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